Advanced Light Source : : Facility Report : : 2007

PUBLISHED BY THE ADVANCED LIGHT SOURCE COMMUNICATIONS GROUP

What’sInside:

2SCIENCE ROUNDUPA selection of ten ALSresearch highlights publishedin 2007

5AROUND THE RINGScientific and technical reports from ALS staff anduser groups

11PEOPLE AND EVENTSBES review, UEC update,high-profile visitors, awards,new faces, etc.

16FACILITY UPDATESBeam delivery, user demo-graphics, construction proj-ects, and new initiatives

Like an “unrolled” car-bon nanotube, graphene isa densely packed single

layer of carbon atomsarranged in a hexagonalpattern like a honeycomb.

Although derived fromgraphite, the form of car-bon in pencils, these two-dimensional graphenesheets may hold the prom-ise of a new generation offaster, smaller, cheaper, andmore durable computerchips than today's silicon-based devices. Conse-quently, interest in the elec-tronic properties of thisform of carbon has surgedworldwide. At the ALS, tworesearch groups, led byAlessandra Lanzara of UCBerkeley and Eli Rotenbergof the ALS, continue to bevery active in this field. In2007, the groups separatelypublished two high-profilepapers exploring graphene'sfundamentally interestingand potentially valuableproperties.

Before graphene can beengineered into transistorsor other electronic devices,

The ALS Graphene Scene

The ALS took a big steptowards the successfulcompletion of the top-offupgrade late in 2007. Therecommissioning of the in-jector complex was suc-cessfully completed anduser operation was movedfrom injection at 1.5 GeV tofull-energy injection at 1.9GeV. Furthermore, therewas further steady progressover the last year in studyingall relevant radiation safety

aspects, culminating in asuccessful outside reviewof the radiation safety track-ing studies and controls.

The transition to top-offmode is motivated by thepossibility of increasingbrightness and improvingthermal stability, keepingthe ALS competitive withnewer light sources for thenext decade. In top-offmode, beam is injected intothe storage ring approxi-

mately every minute to re-plenish lost electrons, asopposed to every eighthours, doubling the averagebeam current, allowing areduction in vertical beamsize, and eliminating thelarge swings in temperaturethat can adversely affectstorage-ring and beamlinecomponents. The plan isbefore the end of 2008 tooperate with top-off injec-tion at 500 mA, which willresult in brightness gains

Top-Off Gets a Boost

The atomic arrangement of graphene (background) is ahoneycomb lattice of carbon atoms arranged in a two-di-mensional plane. Its electronic band structure consists oftwo bands (yellow) that intersect only at a few points atthe corners of a hexagonal Brillouin zone (red).

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Breaking H2 SymmetryMartín et al., Science 315, 629(2007) http://www-als.lbl.gov/als/science/sci_archive/150symmetry-break.htmlA single hydrogen (or deuterium)molecule consists of only two pro-tons (deuterons) and two elec-trons and is perfectly symmetric.Linearly polarized photons aresimilarly symmetric. So one mightthink that the angular distributionof photoelectrons resulting fromphotoionization of the moleculeby the photon accompanied bydissociation into a hydrogenatom and a hydrogen ion woulditself be symmetric. However, aninternational team of researchersfrom Germany, Spain, and theU.S. has now shown that thisneed not be the case. When thereare multiple quantum paths forthe process, interference be-tween waves in the coherent su-perposition of electron states(which exists when the molecularfragments are still close to-

gether) skews the distribution bybreaking the molecular symmetry.

Coherently Condensing PolaronsMannella et al., Phys. Rev. B 76,233102 (2007)http://www-als.lbl.gov/als/science/sci_archive/169manganites.htmlNovel quantum phenomena, suchas high-temperature supercon-ductivity (HTSC) and colossalmagnetoresistance (CMR), arisein certain materials where the in-teractions between electrons arevery strong, but the mechanismdriving their appearance remainsa major puzzle. Now, angle-re-solved photoemission findingsfrom an international team led byresearchers from Stanford Uni-versity and the ALS provide thefirst direct spectroscopic evidencethat the transition from insulatorto metal in CMR manganese ox-ides (manganites) results fromcoherent “polaron condensation.”The new findings also suggest

that coherence-driven transitionsare a generic controlling factorfor novel quantum phenomena indoped transition-metal oxides.

Pt3 Revs Up Fuel CellsStamenkovic et al., Science 315,493 (2007)http://www-als.lbl.gov/als/science/sci_archive/139cathode.htmlTwo out of three of the kineticbarriers to the practical use ofpolymer electrolyte membrane(PEM) hydrogen fuel cells in au-tomobiles have been breached:the impractically high amount ofextra energy needed for the oxi-dation reduction reaction (ORR)on the catalyst and the loss ofcatalytic surface areas availablefor ORR. Using a combination ofprobes and calculations, a groupof scientists has demonstratedthat the Pt3Ni(111) alloy is tentimes more active for ORR thanthe corresponding Pt(111) sur-face and ninety times more activethan the current state-of-the-art

Pt/C catalysts used in existingPEM fuel cells. This new varia-tion of the platinum–nickel alloyis the most active oxygen-reduc-ing catalyst ever reported.

Detangling DNA Dong and Berger, Nature 450,1201 (2007)http://www-als.lbl.gov/als/science/sci_archive/160topoII.htmlThe veil has finally been lifted on anenzyme that is critical to theprocess of DNA transcription andreplication and is a prime target ofantibacterial and anticancer drugs.Researchers at Berkeley Lab andthe University of California, Berkeley,have produced the first three-di-mensional structural images of aDNA-bound type II topoisomerase(topo II) that is responsible foruntangling coiled strands of thechromosome during cell division.Preventing topo II from disentan-gling a cell's DNA is fatal to thecell, which is why drugs that targettopo II serve as agents against bac-

Science Roundup

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–0.2

–0.1

0

0.3

Ene

rgy,

E–E

F (

eV)

Wavevector, k (Å–1)0.4

Sample plot of electron angulardistribution for ionization of deu-terium. The molecule axis is indi-cated by the blue and green circles.The curves represent theory (solidred line), experiment (circles), andfit of the experimental data (dottedline). The three-dimensional plotsare also theoretical results.

ARPES data plots photoelectronintensity variation with energy (rel-ative to the Fermi level) and momen-tum in the nodal direction. Colorrepresents photoelectron intensity.

With Ni (gray) in the subsurfacelayers, the topmost Pt atoms (yel-low) have a modified electronicstructure, which alters different ad-sorption properties of Pt. Conse-quently, interaction between OH–

ions (blue/white) and the Pt skin isweakened, leaving more Pt sitesactive for adsorption of O2 (blue).

High-resolution three-dimensionalcrystallography images of the bind-ing and cleavage core of type IItopoisomerase (topo II) as it inter-acts with DNA.

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terial infections and some forms ofcancer. This first ever structuralimage of topo II should help in thedevelopment of future antibacterialand anticancer drugs that are evenmore effective and carry fewerpotential side effects.

Diamondoids Display PotentialYang et al., Science 316, 1460(2007)http://www-als.lbl.gov/als/science/sci_archive/155diamondoids.htmlDiamondoids are nanometer-sizedmolecules that feature diamond-crystal cage structures. Adaman-tane, the smallest member in thefamily, consists of one cage struc-ture, diamantane two, triamantanethree, tetramantane four, and soon. On all of these, the danglingbonds on the outer surfaces areterminated by hydrogen atoms.Because of their potential to pos-sess novel properties of both dia-mond and nanomaterial, intensiveefforts have been made to synthe-

size the larger diamondoid mole-cules, but to no avail. This situa-tion was finally changed in 2003when significant quantities ofhigher diamondoids were found inpetroleum by researchers in Mo-lecular Diamond Technologies.Now, scientists from Berkeley Lab,Stanford University, Lawrence Liv-ermore National Laboratory, andGermany have used photoelec-tron spectroscopy at the ALS toreveal an intriguing feature: mono-chromatized electron emissionfrom a self-assembled monolayerof diamondoids. This has caughtthe attention of people who aresearching for materials for next-generation electron emitters.

Magnetic CarbonOhldag et al., Phys. Rev. Lett.98, 187204 (2007)http://www-als.lbl.gov/als/science/ci_archive/147carbon.htmlAlthough it has long been sus-pected that carbon belongs onthe short list of materials that

can be magnetic at room temper-ature, attempts to prove that purecarbon can be magnetized haveremained unconvincing. However,using a proton beam and an ad-vanced x-ray microscope at theAdvanced Light Source, a multi-national team of researchers fromthe SSRL, the University of Leipzig,and the ALS finally put to restdoubts about the existence ofmagnetic carbon.

Pushing the Wall Meier et al., Phys. Rev. Lett. 98,187202 (2007) http://www-als.lbl.gov/als/science/sci_archive/153domainwall.htmlThe quest to increase both com-puter data-storage density andthe speed at which one can readand write the information remainsunconsummated. One novel con-cept is based on the use of a localelectric current to push magneticdomain walls along a thin nanowire.A German, Korean, Berkeley Labteam has used the x-ray micro-

scope XM-1 at the ALS to demon-strate that magnetic domain wallsin curved permalloy nanowirescan be moved at high speed byinjecting nanosecond pulses ofspin-polarized currents into thewires, but the motion is largelystochastic. This result will havean impact on the current devel-opment of magnetic storage de-vices in which data is movedelectronically rather than mechan-ically as in computer disk drives.

Nano GoldJadzinsky et al., Science 318,430 (2007)http://www-als.lbl.gov/als/science/sci_archive/164gold.htmlFor the first time, a team of sci-entists led by Roger Kornberghas synthesized thiol-covered goldnanoparticles and, using ALSBeamlines 5.0.2 and 8.2.2 and SSRLBeamlines 11-1 and 11-3, conclu-sively ascertained their atomicstructure (at 1.1 Å resolution). Thegold–thiol nanoparticle consists

Read more about these and other science highlights at http://www-als.lbl.gov/als/science/

DW

Hext

Ferromagnetic Ring

Contact Pads

e–

Tetramantane (inset) consists offour diamond cages fused togetherand terminated with hydrogen.After being functionalized by thereplacement of one of the hydrogenatoms by a thiol group (yellow tip),the molecules will self-assembleinto large-area monolayers onmetal surfaces (purple).

A carbon film is hit by a high-en-ergy proton beam, creating a ring-shaped magnetic pattern that canbe imaged with a magnetic-forcemicroscope. The x-ray microscopecan then be used to “scan” thesample for magnetism associatedwith other elements.

A magnetic domain wall (DW) iscreated between contact pads in apermalloy ring 20 nm thick and 1000nm wide by applying and releasingan external magnetic field (Hext). Afast electronic pulser then launchesshort 1-ns current pulses with acurrent density < 1012 A/m2 into theferromagnetic wire.

X-ray crystal structure determinationof the Au102(p-MBA)44 nanoparticle.

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an energy gap must be intro-duced into graphene's elec-tronic band structure. Whilethere are several promising ef-forts underway to induce such agap, by adding impurities (dop-ing) or fabricating geometricallyconfined structures with one ormore dimensions measured innanometers, the Lanzara grouphas demonstrated that growinggraphene epitaxially on a siliconcarbide substrate so that theatoms on each side of the inter-face maintain their registry couldbe a more reliable approach forgenerating a band gap [Zhou et al.,Nature Materials 6, 770 (2007)].

Working at ALS Beamlines12.0.1 and 7.0.1, the group usedangle-resolved photoemissionspectroscopy (ARPES) to inves-tigate the electronic structureof epitaxial graphene. The meas-urements yielded a map of theband structure (energy vs. mo-mentum) with a sizable energygap of 0.26 eV. However, theFermi energy (maximum en-ergy occupied by electrons) waswell into the conduction band,above where it would be for anormal semiconductor.

In additional experimentswith increasing numbers of

graphene layers, the team foundthat the size of the energy gapdecreased with thickness and allbut disappeared at four layers.Next on the group's agenda arefinding ways to control the widthof the band gap, perhaps by usinga different substrate materialwith a different graphene–sub-strate interaction strength, andto lower the Fermi energy from theconduction band into the bandgap to allow transistor action.

On a more fundamental level,graphene is an ideal playgroundfor exploring “quasiparticle” in-teractions in a solid system.Electrons in solids hardly travelindependently but rather inter-act with a sea of many quasi-particles—collective excitationsthat are responsible for exoticphenomena such as supercon-ductivity. While other materialshave shown signatures of elec-trons interacting with phonons(vibrational excitations) or mag-nons (magnetic excitations), theelectrons in graphene show clearsignatures of scattering fromphonons, plasmons (collectiveoscillations of the electron “gas”),and electron–hole pairs over amuch wider energy scale thanusual. Because the interactions

have similar energy scales, ARPESmeasurements are crucial to de-termining which scatteringevents are most important.

At ALS Beamline 7.0.1, theRotenberg group succeeded inmaking the first ARPES meas-urement of electron lifetime ingraphene over a wide energyscale [Bostwick et al., NaturePhysics 3, 36 (2007)]. In the ab-sence of scattering, the ARPESenergy band of a single layer ofgraphene would be smooth.However, the data clearly showedkinks in the band's shape andvariations in its sharpness that

can only be explained by elec-tron scattering from collectivemodes, including a strong elec-tron–plasmon interaction.

Understanding these inter-actions is not just an academicexercise; it is important becausealthough various forms of carbonare known to be superconduct-ing, the mechanisms are stillunclear. Furthermore, sinceplasmons can also couple to light,the demonstration of strongelectron–plasmon coupling showsthat novel carbon-based deviceswith both electronic and photonicfunctions might be possible.

Graphene continued from page 1

Shuyun Zhou, Alexei Fedorov, and Alessandra Lanzara at ALSBeamline 12.0.1.

Aaron Bostwick and Taisuke Ohta at ALS Beamline 7.0.1.

Eli Rotenberg at ALS Beamline 7.0.1.

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Some of the most excitingfrontiers in materials scienceoccur at the nanoscale, whereself-organization in energy,space, and time often lead tocomplex material properties.Soft x-ray light has the rightwavelength to access the rele-vant spatial scale and core lev-els of the most important ele-ments. Combined withsophisticated spectroscopic andscattering probes, soft x raysgive us a uniquely powerful toolin modern materials science.The goal of our optics researchis to transport, focus, and con-dition the very high brightnessx-ray sources we have and toutilize them in ways that enablenew science at the ALS.

Brightness preservation atthe levels needed—close to thediffraction limit—is extremelydifficult. Very small perturba-tions from a theoretically per-fect optical surface can lead tocatastrophic reductions in per-formance. While this is impor-tant for our current beamlines,where factors of 10–100 maybe lost by use of earlier-genera-tion and nonoptimum optics,it's especially important fornew beamlines such as the ul-trahigh-resolution MERLINbeamline and the proposedMAESTRO and COSMIC beam-lines. In the case of MERLIN,surface slope distortions at thelevel of 0.2 microradians willhave noticeable effect, and newbeamlines drive this valuedown even further, to a rangechallenging to measure andmanufacture. Because thisproblem is not unique to theALS, we recently held a work-shop with leading experts to dis-

cuss the issues. The workshophelped confirm our multi-pronged strategy: pushing exsitu optical lab-based measure-ments as far as possible whiledeveloping in situ measurementtools within beamlines.

At the ALS Optical Metrol-ogy Laboratory (OML), led byValeriy Yashchuk, we collabo-rate internationally on next-gen-eration metrology with targetsensitivity and accuracy wellbelow the 100-nanoradian level.Already, the ALS Long-TraceProfiler II, recently upgraded,and the new slope-measuringinstrument, the DevelopmentalLong-Trace Profiler, have per-formances of 0.25 microradian(rms), comparable to the world'sbest instruments of this type. Auniversal test mirror calibrationmethod under development isnow our strategic direction forfurther improvement toward50-nanoradian accuracy. We havealso developed an originalmethod to calibrate the modu-lation transfer function of mi-croscopes. The method is basedon use of binary pseudo-randomgratings and arrays as surfacestandards, allowing reliable powerspectral density data to be ob-tained for 3D scattering simula-tions of the beamline perform-ance of x-ray optics that are alsounder development at the OML.

An LDRD project, led byDmitri Voronov, explores ahighly promising technology forultrahigh-resolution resonantinelastic soft x-ray scattering(RIXS): fabrication of a super-high-density diffraction gratingfor soft x-ray energies. An x-rayreflecting multilayer is de-posited on an echellette sub-

strate with a relatively lowgroove density; the blazed mul-tilayer grating is then polishedto reveal an oblique cut of themultilayer. The resulting slicedmultilayer structure has a po-tential line density of up to100,000 lines per mm. We (inclose collaboration with aUkrainian research team) havesucceeded in fabricating andtesting a Sc/Si sliced grating with270-nm pitch size (groove den-

sity of ~3700 grooves per mmand total number of grooves of~40,000), the first prototype ofa superdense soft x-ray grating.Measurements performed atBeamline 6.3.2 have demon-strated a high efficiency anddispersive ability in the 41- to49-nm wavelength range. We areworking to extend the technologyto fabrication of an ultrahigh-density grating for soft x rays,

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Experimental Systems Group: Focus on Opticsby Howard Padmore

The Advanced X-Ray Optics Metrology for Nanofocusing and Co-herence Preservation workshop at the 2007 ALS Users' Meeting,organized by Kenneth Goldberg and Valeriy Yashchuk. Featuring11 invited talks, the workshop brought together industry represen-tatives and researchers from Japan, Europe, and the US to discussthe state of the art and outline the optics requirements of newlight sources.

Fabrication of Sc/Si sliced grating with 270-nm pitch size, firstprototype of a superdense soft x-ray grating suitable for the EUVphoton energy range.

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where we anticipate spectro-graph systems of high efficiencyand throughput up to 1 keV, forresolving powers above 105.

Zone-plate lenses are thecore component of x-ray imagingsystems but have a resolutionlimited by nanolithography andan intrinsic limit set by samplethickness and the depth of fieldof the lens. Within the last tenyears, led by the pioneering workof Janos Kirz and colleagues, anew form of imaging based onscattering a coherent x-ray beamhas become popular because itsresolution is, in principle, lim-ited only by the wavelength ofthe light. Phase information is lost,but can be reconstructed nu-merically, using prior knowledgeof the area containing the sample.This reconstruction can now bedone relatively routinely, butthe use of constraint informa-tion is experimentally limiting andis computationally challengingfor reasonably sized images.

Fourier-transform x-ray holo-graphy (FTXH) avoids these lim-

itations by “phasing” the scat-tered beam directly with a ref-erence beam, usually providedby a hole in the object. The dis-advantage is that the interfer-ence provided by the referencebeam is weak. An international,multilab team led by StefanoMarchesini has developed atechnique that produces x-rayholograms three orders of mag-nitude more intense than previ-ously possible. The techniqueis a variant of normal FTXH butuses a uniformly redundant ar-ray (URA) as the reference ob-ject, greatly increasing bright-ness at the maximum resolution.The Marchesini team has usedthe technique at Beamline 9.0.1to record a hologram of ananofabricated test object at 2.3nm and images of bacterial cellswith a resolution of 45 nm in 15fs using the FLASH free-elec-tron laser. This technique al-lows direct inversion of thescattering patterns to imageswithout any iterations, over-comes the tradeoff between sig-

nal-to-noise ratio and resolu-tion, and provides phase andamplitude contrast informationsimultaneously. Existing litho-graphic methods could push the

resolution to ~15 nm. Diffractiveimaging reconstruction methodscould push the resolution be-yond the nanofabrication limitto a few nanometers.

Illustration of FTXH using a URA as a reference object.

MAESTRO, the Microscopicand Electronics Structure Ob-servatory, is the new facilityplanned to replace the existingphotoemission branchlines atBeamline 7.0.1 and features anew dedicated “half” insertiondevice capable of full polariza-tion control above 60 eV and anew entrance-slitless mono-chromator capable of 3-meVresolution from 20 to 100 eVand extended operation up to1000 eV. The new beamline'sdesign effort, together with plansfor decommissioning the exist-ing beamline, were begun thisyear to support an applicationto DOE to fund a new facility

dedicated to nanoARPES: angle-resolved photoemission spec-troscopy with 50-nm probe size.

A new infrared beamline,dedicated to environmental andbiological studies with near-in-frared light, is now being de-veloped. The new beamline, tobe situated at Sector 5, will acceptdouble the light of the existingIR beamline and is expected tohave superior stability.

The MERLIN beamline,planned to achieve the ultimateresolution for ARPES at theALS, has been designed, and as-sembly on the ALS floor has be-gun. The beamline features the

Scientific Support Group: State-of-the-Art Instrumentation for World-Class Science

by Eli Rotenberg

Coil

YokeMount

PoleYoke Vacuum

CoolingVacuum

ChamberEight-pole electromag-net installed at ALSBeamline 4.0.2 providesmagnetic fields of up to0.8 T in arbitrary direc-tions, crucial for thestudy of the XMLD an-gular dependence.

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Beamlines 5.0.1, 5.0.2,and 5.0.3. An upgrade of the x-ray optical elements in all Sector5.0 beamlines was completedin early 2007. The performanceof Beamline 5.0.2 was improvedby a factor of 3 to 4 and nowsurpasses the performance ofthe macromolecular superbendbeamlines at the ALS, generating8 × 1011 photons per second at10 keV and 400-mA ring current.This has had a tangible impacton the ability of users to per-form experiments. User groupsworking on membrane proteinsystems have been able to solvestructures that otherwise werenot tractable. Other users work-ing with crystals of a large macro-molecular complex were ableto collect diffraction imageswith 15-second exposures insteadof the 120 seconds required onother beamlines at the ALS.

Replacement of the M101and M301 mirrors significantlyimproved the performance of theside-station beamlines (5.0.1 and5.0.3). A 5- to 10-fold improve-

ment in available flux wasachieved, now generating 1.5 ×1011 photons per second at 12.4keV. In February 2007, the 5.0.1monochromator was replacedwith crystals that improve beamfocusing and also select x raysslightly above the selenium peakin order to enable single-wave-length anomalous diffractionexperiments with selenium-de-rivatized proteins.

Beamlines 8.2.1 and8.2.2. In early 2007, the Berke-ley Center for Structural Biol-ogy (BCSB) received a $4.8 mil-lion award from the HowardHughes Medical Institute (HHMI)to upgrade Beamlines 8.2.1 and8.2.2 (which are operated forHHMI). The upgrades include theinstallation of robot equipmentfor sample mounting, high-pre-cision instrumentation for crys-tal handling, a larger CCD de-tector for data collection, andimproved x-ray optics to gener-ate a 30-micron beam once thetop-off upgrade is complete.

In June 2007, BCSB staff

completed the installation of aRigaku ACTOR robotic sampleautomounter on Beamline 8.2.2.This robot is able to automati-cally transfer user samples froma liquid nitrogen dewar into theexperimental data collectionarea without any manual inter-vention. This permits users tooperate the beamline withoutthe need to open the experi-mental hutch. In the near fu-ture it will be possible for usersto run their experiment re-motely after sending the sam-ples to the BCSB staff for load-ing into the dewar.

Macromolecular Crystallography Improves Brightness, Automation

by Paul Adams

Performance of the Sector 5.0 beamlines after the 2007 x-ray optics upgrade.

Rigaku ACTOR crystal auto-mounter robot installed onBeamline 8.2.2.

The Center for X-Ray Op-tics (CXRO) has made signifi-cant progress both scientificallyand technologically in its imaging,metrology, and industry-fundedEUV lithography research pro-grams. The leading researchperformed at the Center's nano-

fabrication and coating facilitiesenables it to provide high-reso-lution diffractive optics, coat-ings, and other nanostructures,for its own activities and for thesupport of other ALS activities.

The full-field soft x-ray mi-croscope at Beamline 6.1.2 is a

unique tool for nanoscience,combining high spatial resolu-tion (15 nm) and temporal reso-lution (70 ps) with a rich set ofcontrast mechanisms: elemen-tal, chemical, topological, andmagnetic. Magnetism researchusing this microscope is impor-tant to the development of high-density and high-speed mag-netic storage media. Time-resolved x-ray images of thevortex core motion revealed forthe first time the degree of spin

polarization of conduction elec-trons, and magnetic domainstructure analysis of nanogran-ular CoCrPt thin alloy filmsconfirmed a stochastic behaviorin the domain nucleation process.

Specialized zone plates areextending imaging capabilitiesat the microscope. Depth of fieldextension with the cubic zoneplate and wavefront coding tech-nique, performed at Beamline6.1.2, provides a method for

Imaging, Metrology, and EUV Lithography at CXROby Erik Anderson

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overcoming the depth-of-field–limited resolution for soft x-raytomography. Spiral and Zernikezone-plate imaging, demonstratedat the coherent optics Beamline12.0.2.1, enhances contrastthrough phase sensitivity.

The Micro Exposure Tool(MET) on Beamline 12.0.1.3 pro-vides the world's highest-reso-lution EUV printing for resistand mask research. Resist inno-vations are pushing the envelopeof resolution (22-nm half-pitchlines), sensitivity, and line-edgeroughness. Collaborative effortsat the MET and the metrologyBeamline 6.3.2 unraveled a sys-tematic underestimation of the

sensitivity of resists. Fortunately,this reduced the required sourcepower, which invoked a collec-tive sigh of relief from the in-dustry. The EUV zone-plate mi-croscope on Beamline 11.3.2

emulates the optical parametersof EUV lithography tools and isdedicated to photolithographymask research. As the highest-performing tool of its kind, itserves a broad group of semi-

conductor company researchersby finding and classifying maskdefects as small as 20 nm wideand 1 nm tall and by validatingthe effectiveness of repair andcleaning strategies.

Scientific investigations atBeamline 11.0.2 are split be-tween two experimental capa-bilities: a scanning transmissionx-ray microscope (STXM) andan ambient-pressure photoelec-tron spectrometer (APPES).Spectroscopy and microscopyin the soft x-ray region are ex-cellent tools for probing envi-ronmentally relevant samplesunder realistic conditions, i.e.,with water or water vapor pres-ent at ambient temperature.

While other microscopiesprovide exquisite images or ele-mental content, none offers thechemical specificity of STXMwith comparable spatial resolu-tion. The spatially resolvedchemical information, with res-olutions of 25–35 nm, is unique.

Investigations include studies ofmagnetic materials, actinide, at-mospheric and cometary par-ticulates, synthesized or natu-rally occurring nanoparticles,biofilms, mineral–bacteria sus-pensions, and polymers. Exper-iments on magnetic materialsprobe changes in the magneti-zation vector during exposureto magnetic or spin polarizedelectric fields. This relaxation,reversal, or precession of the mag-netization vector is examined intime-resolved experiments (70 ps)and addresses scientific issuesrelated to information storagein magnetic materials. The dis-covery at the STXM of low-fieldswitching of magnetic vortexcores may lead to a new type ofmagnetic memory. Linear dichro-

ism microscopy studies includenaturally occurring materialsand organic nanomaterials. Themagnetic and linear dichroism

experiments are uniquely fea-sible due to the combination ofthe insertion device (EPU) and

CXRO

by Hendrik Bluhm, Mary K. Gilles, Tolek Tyliszczak, and David K. Shuh

(a) Magnetic domains in a CoCrPt nanogranular alloy thin film imaged at the Co L3 edge with 15-nmspatial resolution. Scale bar is 120 nm. (b) SEM image of the spiral zone plate. (c) 22-nm spatial reso-lution patterning with a high-sensitivity EUV resist.

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Figure 1. Left: Carbon K-edge NEXAFS spectral components.Center: Size and composition of collected particles determined bySTXM: organic particles (OC, green), inorganic particles sur-rounded by annular organic shell (InOC, blue), mixed organic inor-ganic elemental carbon particles (ECOC, red) and mixedinorganic, elemental and organic carbon (InECOC). Right: Numberfraction and number size distribution indicate a systematic in-crease in number of particles with organic composition as a func-tion of distance downwind from central Mexico City (T0) to T1 toT2. (R.C. Moffet et al., in preparation)

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Molecular Environmental Science Under Realistic Conditions

first quasiperiodic undulator atthe ALS—designed to minimizethe contaminating higher har-monics that plague the existingARPES experiments—and is ex-pected to achieve sub-1-meVresolution for the first time at abeamline for condensed matterstudies at the ALS. Operationis expected in early FY09.

At the Electronic StructureFactory endstation, we havecommissioned a new liquid-he-lium-cooled goniometer, capa-ble of temperatures from 11 to2000 K and compatible with theprevious sample holder design.

HARP, the Beamline 12 pho-toemission endstation, will becompletely replaced with a new

chamber featuring an upgradedanalyzer: the SES-R3000. Thisanalyzer features about 1.8times the throughput for agiven resolution, and almostthree times the maximum an-gular acceptance, of the previ-ous analyzer, and will achievearound five times improvedthroughput over the old ana-lyzer. Together with a recent up-grade to the x-ray optics, the

new capabilities will enhancethe effectiveness and alleviatecrowding at one of the mostoversubscribed endstations atthe ALS.

The SSG group strives tocreate state-of-the-art instru-mentation to enable new sci-ence. The following selectedhighlights reflect not onlyworld-class science but illus-trate the unique capabilities cre-ated in the ALS by the SSG.

The x-ray magnetic lineardichroism (XMLD) spectrum oftransition-metal ions in mag-netic materials is a very com-plicated function of the relativeangles between photon polar-ization and crystalline and mag-netic polarization directions,and from this function we canderive rich information aboutthe coupling of spins in mag-netic systems. SSG's Elke Aren-holz, in collaboration with Y.Suzuki's group (UC Berkeley)and G. van der Laan (Dares-bury), have shown that the fulldouble angular dependence ofthe Ni XLMD in a NiO/Co in-terface can be modeled by twofunctions that depend only theatomic multiplets involved inthe Ni 2p level probed, togetherwith the detailed symmetry ofthe materials [Arenholz et al.,Phys. Rev. Lett. 98, 197201 (2007)].In fact, these results can be ap-plied generally to Ni in any sim-ilar cubic environment, even insituations previously approxi-mated by only one angularfunction. Consequently, previ-ous results will have to be reex-amined to derive a true under-standing of the magnetic states.

A study led by J. Banfield(UC Berkeley) used infraredspectroscopy as well as othertechniques to analyze dense ag-gregates of bacterially formed

9

The Chemical DynamicsBeamline 9.0.2 provides state-of-the-art experimental resourcesto undertake studies of funda-mental chemical processes usingVUV radiation. Projects under-taken at the beamline in 2007included chemical reactions onmodel particle surfaces reflec-tive of atmospheric aerosols anddiesel exhaust, molecular growthmechanisms relevant to com-bustion chemistry and astro-chemistry, details of hydrogenbonding and structure of smallwater and alcohol clusters, gasphase microhydration studies ofDNA bases, flame chemistry ofbiofuel surrogates, elementary

reaction kinetics of hydrocarbonradical reactions with relevanceto combustion and the atmos-phere of Titan, and the pho-toionization of dopants in ultra-cold helium droplets. Of themany interesting results ob-tained, four are of particular in-terest: Angle-resolved thresholdphotoelectron spectra recordedfor size-selected beams ofsodium chloride nanoparticles(radius = 25–250 nm) exhibit asize-dependent asymmetry thatis inversely proportional to par-ticle radius. The internal elec-tric field amplitude and the pho-toelectron escape probabilityinside the particles were mod-

eled and accounts for the ob-served asymmetry (Wilson etal., Nano Lett. 7, 2014 (2007)]. Anovel multiplexed time-resolvedphotoionization mass spectrom-eter technique has been em-ployed to investigate the ioniza-tion behavior of two 1-alkenylperoxy radicals, which play keyroles in low-temperature oxida-tion and photo-oxidation of hy-drocarbons (Meloni et al., JACS129, 14019 (2007)]. An experi-mental study that provides in-formation about the photoion-ization energies of small carbonclusters was undertaken. Cou-pled with elaborate electronicstructure calculations, insightwas provided into the structureand composition of thesespecies in a laser-ablated super-sonic molecular beam (Belau etal., JACS 129, 10229 (2007)].Photodissociation and pho-toionization experiments sug-gest that, in Titan's upper at-mosphere, VUV radiation mayplay an important role in theformation of complex organicmolecules through photoioniza-tion of N2 (Imanaka and Smith,GRL 34, L02204 (2007)].

Chemical Dynamics from Table Salt to Titanby Musa Ahmed

Photoelectron imaging of size-selected nanoparticles exhibit asize-dependent asymmetry that is inversely proportional to parti-cle radius.

RING AROUND THE RING AROUND THE RINGAROUND THE RING AROUND THE RING

continued on page 10

SSG continued from page 6

10

accessible energy range (130–2000 eV) at this beamline. Dueto the minute amounts of mate-rial needed for STXM experi-ments (10 fg for a particle), a va-riety of radioactive materialscan be safely studied.

Particulate studies examinedifferences in the chemicalbonding of a particular element.Atmospheric particles collectedat ground sites, successively dis-tant from Mexico City, show anincrease in the number of par-ticles containing organic carbon(Figure 1). This increased oxi-dation results from atmosphericprocessing and influences theparticles' water solubility andatmospheric lifetime. TheAPPES endstation is excellentfor probing liquid/vapor andsolid/vapor interfaces at Torrpressures. This is ideal for ex-amining the chemistry of inter-faces, the role of water, and forprobing changes in the inter-face arising due to chemical re-actions. Under identical relativehumidity (5%), water wetsCu(110), but not Cu(111) (Fig-ure 2). However, if the Cu(111)surface is partially covered by

oxygen, water does wet Cu(111).The wetting is controlled by thepresence of OH groups on thesurface, acting as anchors forwater adsorption. This behaviorresults from the difference inthe dissociation barrier for thetwo surfaces: Cu(110) < Cu(111).When Cu(111) is partially cov-ered by atomic oxygen, its dis-sociation barrier is decreasedand hydroxylation and wateradsorption are observed.

Experimental capabilities atBeamline 11.0.2 are in a con-stant state of improvement. Theendstation area was substan-tially rearranged to provide op-timal space for experiments.Major STXM developments in-cluded improved timingschemes for time-resolved ex-periments, experiments em-ploying fluorescence or electronyield detection as well asprogress in tomography and thedevelopment of a mini-STXM.Improvements related to theAPPES endstation include thedevelopment of a separatedroplet train apparatus, newmaterial sources, and the addi-tion of new turbopumps.

metal sulfide nanoparticles[Moreau et al., Science 316, 1600(2007)]. They found that pro-teins trapped within thenanoparticles may have playeda key role in the aggregationprocess. Sulfate-reducing bacte-ria can lower the concentrationsof metals in anoxic waters bysequestering metals intonanoparticles. The worry is thatthese very small particles couldbe highly mobile, redissolvingquickly if conditions change.The results presented in the pa-per, however, suggest that mi-crobially derived extracellular

proteins can limit dispersal ofnanoparticulate metal-bearingphases, such as the mineralproducts of bioremediation thatmay otherwise be transportedaway from their source by sub-surface fluid flow. This workused the high spatial resolutionof Beamline 1.4.3 to spectrallyidentify the presence of proteinswithin these nanoparticles.

Colloidal nanocrystals (crys-talline nanoclusters suspendedin liquid) were analyzed using acombination of x-ray absorptionand emission spectroscopies atBeamline 7.0.1 [Liu, et al., NanoLetters 7, 1919 (2007)]. Becausethese techniques normally areconducted on solids in ultrahighvacuum, application to nanocrys-tals in liquid required develop-ment of a new water cell withsufficiently thin windows to al-low the x rays to be absorbedand emitted to the detector.Special care was taken to pro-tect the beamline and the syn-chrotron from accidental vent-ing. The principle finding wasthe ability to discriminate thechemical state of Co atoms inthe interior of clusters fromthose on their surface. The dis-tinguishing feature of theseatoms is that the surface atomshave a different chemical statedue to charge transfer to ligandmolecules that were used tofunctionalize the nanocrystalsurfaces. The technique shouldfind wide application to manyfuture studies, since such func-tionalization can be used to tai-lor the properties of new mate-rials for a variety of needs,including magnetism, electron-ics, and energy collection.

Top: Illustration of a colloidalnanocrystal with a cobalt cen-ter surrounded by a ligand layermade up of molecules of an or-ganic surfactant (oleic acid).Bottom: Transmission electronmicroscope (TEM) image ofcobalt nanocrystals. Scale bar= 50 nm.

RING AROUND THE RING AROUND THE RINGAROUND THE RING AROUND THE RING

Molecular Environmental ScienceSSG continued from page 9 continued from page 8

Figure 2. Differences in oxygen bonding between Cu(111) andCu(110) surfaces (S. Yamamoto et al., J. Phys. Chem. C 111, 7848 (2007)].

11

P E O P L E A N D E V E N T S

Pedro Mon-tano, DOE Ba-sic Energy Sci-ences (BES)Scientific User

Facilities Division Director, hassent me a summary of the re-port from the triennial DOEBES review of the ALS that washeld last March, and I am ex-tremely proud of the results. Toquote the opening paragraph,“The ALS scientific output con-tinues to excel with an excep-tional percentage of publica-tions in the 'high impact'category. This reflects positivelyon its world-class beamline ca-pabilities and outstanding sci-

entific staff.” This is high praiseindeed, only made possible bythe contributions of all mem-bers of the ALS staff and usersworking together.

I would like to share withyou some of the observations.Reviewers noted that the ALS hasmade significant improvementsfor the user community, includ-ing a web-based proposal systemdescribed as being transparentand fair. They also commendedALS Safety Program ManagerJim Floyd's collaborative styleof working with users to imple-ment pragmatic safety measures.

There was praise for theprogress made toward top-off

operation, as well as for severalinstrument achievements, in-cluding the new EPU Beamline11.0.1 and the steps taken to-ward the PEEM3 microscope;superbend Beamline 12.3.2,which extended the energy rangefor white-beam x-ray Laue mi-crodiffraction and provided en-hanced strain sensitivity; theprogress on Beamline 4.0.3(MERLIN), including an aperi-odic undulator for harmonic re-jection; and the move of the ul-trafast program to Sector 6.0,which resulted in much im-proved intensity on the high-and low-energy branch lines.

Finally, reviewers were im-pressed by the strong interac-tions between the ALS and boththe Scientific Advisory Com-mittee (SAC) and the Users' Ex-

ecutive Committee (UEC). Theyalso commented favorably onthe ALS Strategic Plan andpointed out that the ALS hastaken the lead in establishing agraduate student and postdocsupport program, vital to devel-oping a pipeline for future beam-line and accelerator scientists.

Other than our well-knownstaffing shortages, no majorshortcomings were identified inthe review. Dr. Montano's letteraccompanying the report sum-mary concludes by “commend-ing the ALS on continuing itsoutstanding scientific outputand instrument development,”a view I heartily share.

This was a gratifying re-view, a testament to our collec-tive efforts at the ALS. I thankeveryone for a job well done.

High Praise for the ALS in BES Triennial Review Report

The ALS Users'E x e c u t i v eC o m m i t t e e(UEC) repre-sents more than2000 scientists

worldwide who are using theALS for their research and ithas been my pleasure to serveas the UEC chair this past year.In order to assist ALS users, thatis you, we interact very closelywith ALS management, repre-sent you during external re-views, and voice your concernsto various groups on CapitolHill. In all of these capacities,the UEC addresses a large vari-ety of topics and issues, rangingfrom facility access, safety reg-ulations, user housing, ALS up-grades to congressional support

for DOE facilities.This has been a truly excit-

ing year for the ALS. In Marchthe ALS hosted the triennial fa-cility review by the DOE. Thereview committee was very im-pressed with the quality of theresearch conducted at ALS andby the level of support that sci-entists, engineers, technical andadministrative staff provide tousers in order to facilitate theirresearch programs. Congratula-tions and a big thanks to every-body for a job well done! It willrequire the continued efforts ofall of us to ensure that the ALSwill be able to provide top-levelsupport to its users leading tooutstanding science in the fu-ture in the light of dire currentand future budget scenarios.

This has also been a year ofvisible changes around the ALSbuilding. Already last years Users'Meeting featured the ground-breaking ceremonies for theUser Guest House and the UserSupport Building, and the con-struction work on the guest houseis making good progress. Un-fortunately, the start of con-struction for the USB had to bedelayed due to the budget short-fall, but work on the foundationwill begin during the fall shut-down. In the past, one of ourmajor concerns was the shortageof lab and office space and thelack of on-site accommodationsduring beam time. Thanks to theefforts of the ALS User ServicesOffice, ALS management, andprevious UECs as well as yourcontinued support, we will soonbe able to put these issues be-

hind us.Finally, I want to thank you

for your support and help andwould like to ask you to workclosely with next year's UECchair Kenneth Goldberg to en-sure that the ALS continues tobe an outstanding facility forsynchrotron radiation scienceworldwide. I would also like tothank Wayne Stolte and PhilHeimann, the program chairsof the 2008 Users' Meeting. To-gether with the help of Sue Bai-ley and her team at the ALSUser Services Office, they puttogether an outstanding pro-gram for the 2008 Users' Meet-ing with exciting and informa-tive plenary sessions as well asa list of excellent workshops.

I wish all of you an enjoy-able, exciting, and productivefuture at ALS.

Users' Executive Committee Update

by Roger Falcone

by Hendrik Ohldag, 2008 UEC Chair

12

On March 31, 2007, the Di-rector of the National Institutesfor Health (NIH), Elias Zer-houni, visited Berkeley Lab andthe UC Berkeley campus. Aspart of his visit, he toured theALS with Graham Fleming (for-mer Berkeley Lab Deputy Di-rector), Roger Falcone (ALS Di-rector), Paul Adams (Head ofthe Berkeley Center for Struc-tural Biology), and CarolynLarabell (Director of the Na-tional Center for X-Ray Tomog-raphy). The BCSB has fivebeamlines optimized for macro-molecular protein crystallography.The NCXT carries out researchin biological and biomedical im-aging and cell biology.

Director Zerhouni's tour ofthe BCSB beamlines included alook at Beamline 5.0.3's new 315rCCD detector and the BerkeleyAutomounter System (developedby Thomas Earnest and col-leagues at Berkeley Lab). Adamsdescribed the upcoming up-grades to Beamlines 8.2.1 and8.2.2, and Zerhouni respondedenthusiastically about the pros-pects for increased automation

of crystallographic experiments.As part of his tour, Zerhouni

also inspected the NCXT'snewly constructed soft x-ray mi-croscope. This is the first suchmicroscope to be designed andbuilt specifically for biologicaland biomedical imaging. (TheNCXT is an NIH National Cen-ter for Research Resources thatalso receives joint funding fromthe Department of Energy, Of-fice of Biological and Environ-mental Research.)

Zerhouni, a radiographerwith considerable experience infull-body CAT scanning, wasenormously enthusiastic aboutthe potential of the new tech-nique and told the assembledgroup, “I love this stuff!” Near-ing the end of the NCXT tour,Mark Le Gros, the Berkeley Labscientist responsible for the de-sign and construction of thenew microscope, showed Zer-houni his latest innovation, aninstrument for a techniqueknown as correlated mi-croscopy. At the end of his in-spection of the NCXT beamline,Director Zerhouni, with overallresponsibility for the NIH's $29billion budget, beamed andsaid, “This was money wellspent!”

NIH Director Visits the ALS

NIH Director Elias Zerhouni, NCXT Director Carolyn Larabell, andformer Berkeley Lab Deputy Director Graham Fleming at the NCXT.

P E O P L E A N D E V E N T S

Daniel Chemla, former director of the ALS andMaterials Sciences Divisions and major intellec-

tual driver in the establishment of the MolecularFoundry, died at home on Thursday, March 20,2008, at the age of 67. He had been battling a se-ries of health problems since suffering a strokefour years ago. Despite those difficulties, he con-tinued to actively lead his research group untilvery recently.

As ALS Division Director, Daniel's ambitious20-year roadmap for the ALS laid the groundwork for new beam-lines, accelerator upgrades, and expanded scientific programs inmaterials sciences, ultrafast science, microscopy, and protein crys-tallography. During his seven-year tenure at the ALS, the numberof users grew from 659 to over 2000. He stepped down as direc-tor in 2005. Acknowledging Daniel's extraordinary contributionsto the ALS, current ALS Director Roger Falcone observed, “He wasa visionary and tireless leader. He set the ALS on a path of fron-tier science that we continue today, as was pointed out explicitlyin the recent BES review. As a teacher and researcher, Daniel wasinspirational for his students and colleagues. Along with his ex-tensive network of friends, I will greatly mourn his passing, whileappreciating his extraordinary life.”

Daniel is survived by his wife Berit, two children, Yann, an as-sistant professor of physics at the University of Illinois, Urbana-Champaign, and Britt Chemla Jones, an art history lecturer inHouston, Texas. To read the full obituary on the ALS Web site, goto http://www-als. lbl.gov/als/news/chemla.html.

Gary Krebs, the popular leader of the ALS UserServices Group, passed away suddenly on theevening of May 22, 2007, in the midst of travel toLong Island for his annual visit to attend the Na-tional Synchrotron Light Source (NSLS) user meet-ing at Brookhaven National Laboratory.

Since arriving at the ALS in 1993, Gary had ma-jor impacts in several important areas: bringing

the nascent accelerator survey and alignment system into adult-hood as a functioning, productive tool, leading the first User Serv-ices Group as it evolved to serve an ever-larger user community,and as the ALS representative to the Lab group that has been for-mulating plans for the on-site Berkeley Lab Guest House. For thelast two years, he also served as Deputy Scientific Director to thelate Neville Smith and then as Deputy Science Advisor to JanosKirz. “Over the past three years I had the privilege to work closelywith Gary, and I learned a lot from him,” said Janos. “He was de-voted to the ALS, and in particular to the users of the ALS. Heworked hard to make the Guest House a reality, and his efforts arenow bearing fruit. His passing is a great loss to all of us, and to mepersonally.”

In addition to his wife Kathy, he leaves behind one son,Matthew, and in Vancouver, British Columbia, a brother, Dennis,and his parents. To read the full obituary on the ALS Web site, goto http://www-als.lbl.gov/als/news/krebs.html.

In Memoriam

13

P E O P L E A N D E V E N T S

The 13th biennial meeting of the Beam Instrumentation Work-shop (BIW) took place at Lake Tahoe on May 4–8, 2008. It wassponsored by Berkeley Lab's Accelerator and Fusion Research, En-gineering, and ALS divisions. This international conference onbeam diagnostics and instrumentation for accelerators is probablythe most important gathering in the field of beam instrumentation,together with its European counterpart, the Diagnostics for Parti-cle Accelerators Conference (DIPAC), which alternates with BIWon alternate years. The conference offers formal presentations, aposter session, and informal discussions to promote the exchangeof ideas and issues between scientists, engineers, and representa-tives of companies operating in the field. Approximately 120 peo-

2008 Beam Instrumentation Workshop

Asilomar Conference Center.

Interest in coherent x-ray science is increasing rapidly, both inthe areas of diffraction microscopy and x-ray photon correlationspectroscopy. The first workshop devoted to these topics was heldin Berkeley in 2001. This was followed by gatherings in Cairns,Australia (2003), and Porquerolles, France (2005). The most recentworkshop took place at the Asilomar Conference Center nearMonterey on June 25–28, 2007. It was attended by 150 practi-tioners (50 more than anticipated) from all parts of the world. Inaddition to more than 30 talks, 70 posters were presented, show-casing progress on both the experimental and theoretical fronts. Inaddition to ongoing work and plans for new beamlines at third-gen-eration light sources, new results from FLASH [the x-ray free-elec-tron laser (FEL) in Hamburg] and from laboratory-scale x-raylasers were discussed, as well as plans for experiments at x-rayFELs under construction on three continents.

The workshop was sponsored by the ALS, the Center for X-RayOptics, Lawrence Livermore National Laboratory, and the Centerfor Biophotonics at the University of California, Davis. The postersessions and banquet were further enlivened by refreshmentsgenerously contributed by XRADIA. The program and abstractscan be found on the conference Web site at http://www-als.lbl.gov/coherence2007/.

Coherence 2007 Workshop Draws Record Attendance

BIW08 conference attendees pose for a group photo outside theGranlibakken Conference Center and Lodge near Lake Tahoe, California.

Left to right: Julien Bergoz (Faraday Cup Award sponsor), SurenArutunian (2008 Faraday Cup Award recipient), and Fernando San-nibale (BIW08 chair).

ple attended, tutorial sessions served as introduction to relevanttopics, and a vendor exhibition allowed participants to get updatedinformation on related commercial products.

The Faraday Cup Award, which recognizes and encourages in-novative achievements in the field of particle accelerator beam in-strumentation, was presented during the workshop. The awardconsists of a money prize and a certificate, and the BIW programcommittee is solely responsible for the selection of the recipient.This year's winner is Suren G. Arutunian, of the Yerevan PhysicsInstitute, Yerevan, Armenia, for the development, publication, andsuccessful testing of the diagnostic system, “Vibrating Wire Scanner.”

Fernando Sannibale of the ALS Accelerator Physics Group wasthe BIW08 chair this year, and the local organizing committee wascoordinated by Joy Kono of the ALS. Berkeley Lab's contributionincluded three invited talks, one contributed talk, and two posters.More information on BIW08 and its program (including PDF filesof the presentations) can be found at the conference Web site athttp://www-als.lbl.gov/biw08/. The proceedings of the conferencewill be published on the Joint Accelerator Conferences Website (JA-CoW), the free-access database for particle accelerator confer-ences, at http://accelconf.web.cern.ch/AccelConf/.

14

P E O P L E A N D E V E N T S

ALS user Franz Himpsel wonthe 2007 Davisson-Germer Prize

“for pioneeringinvestigations ofthe electronicstructure of sur-faces, interfaces,adsorbates, andnanostructures.”Himpsel hasbeen a long-

time involved and dedicatedALS user. He was part of thegroup that argued for the estab-lishment of the ALS, wasamong the team that built oneof the first two undulator beam-lines, and later took part in thedevelopment of a nano-NEX-AFS endstation at Beamline8.0.1. He served on the ALS Sci-ence Policy Board and Users'Executive Committee. Himpselis a pioneer in the field of sur-face science using synchrotronradiation and is also a long-timeuser of the Synchrotron Radia-tion Center (SRC) in Madisonand served as its Scientific Di-rector from 1997 to 2002.

Sam Bader, member and pastchair of the ALSScientific Advi-sory Commit-tee, received the2007 DavidAdler Lecture-ship Award forhis “spirited lec-

tures, writing and experimentalresearch in the area of nano-magnetism, magnetic films, mul-tilayers and surfaces of metallicsystems, including championingthe surface magneto-optic Kerreffect approach.” The awardwas presented at the Marchmeeting of the American Phys-ical Society, where Bader gavean invited talk in the awardssession of the Division of Mate-rials Physics. Bader is an Ar-gonne Distinguished Fellow andcurrently serves as Chief Scien-tist of the new Center forNanoscale Materials and as As-sociate Division Director andgroup leader in Argonne's Ma-terials Science Division.

Former ALS postdoc and cur-rent user ByronFreelon has beenawarded thefirst MorehousePrize by the Na-tional Society ofBlack Physicists(NSBP), whichrecognizes grad-

uates of historically black col-leges and universities who haveshown considerable promise asphysics researchers and teach-ers. The prize was awarded forhis work in x-ray Raman scat-tering on artificial supercon-ducting materials and his strongsupport of NSBP student pro-

grams. Freelon accepted theaward at Morehouse College onApril 5 and gave a talk entitled“Probing High-Temperature Su-perconductors with Layers andLight.” Freelon attended PrairieView A&M University and re-ceived a Ph.D. in physics from theUniversity of Minnesota in 2001.

Chuck Fadley, long-time ALSuser, ALS Professor, and aphysicist with Berkeley Lab'sMaterials Sciences Division andat UC Davis, was presented with

an award fromthe JapaneseSociety for thePromotion ofScience for hisdevelopment ofcharacterizationmethods basedon photoelec-

tron spectroscopy and synchro-tron radiation and for his men-toring of young scientists. Fadleyreceived the award while at-tending the Sixth InternationalSymposium on Atomic-LevelCharacterization for New Mate-rials and Devices in Kanazawa,Japan. He is one of the world'sforemost practitioners of photo-electron spectroscopy.

In 2007, ALS Deputy DivisionDirector Ben Feinberg (now re-tired) was one of five BerkeleyLab scientists selected as a fel-low of the American Associa-tion for the Advancement ofScience (AAAS). AAAS fellows,

a tradition thatbegan in 1874,are chosen bytheir peers fortheir distin-guished contri-butions to sci-ence research,teaching, tech-

nology, or administration. Benwas elected “for outstandingcontributions to user facilities,especially the Advanced LightSource.” Ben and the other newfellows were recognized fortheir contributions at the Fel-lows Forum on February 16,2008, during the AAAS AnnualMeeting in Boston.

Howard Padmore, ALS DivisionDeputy for Ex-perimental Sys-tems, has beenelevated to therank of fellowby the OpticalSociety of Amer-ica (OSA) Board

of Directors at their meeting inSeptember 2007 in San Jose, Cal-ifornia. OSA members whohave served with distinction inthe advancement of optics areeligible for nomination to therank of fellow. The number offellows is limited to ten percentof the total membership. TheSociety recognizes Howard forhis pioneering contributions tothe application of x-ray optics toscientific research using syn-chrotron radiation.

Honors and Awards

Himpsel

Bader

Freelon

Fadley

Feinberg

Padmore

15

P E O P L E A N D E V E N T S

Peter Denes of Berkeley Lab'sEngineering Division has joinedthe ALS as our Deputy for En-gineering. “Peter has been aleader within Engineering andin detector development at theLab, and we're now looking for-ward to his playing a larger rolein these efforts for the ALS,”said Roger Falcone, ALS Divi-sion Director.

In the Engineering Division,Denes was responsible for elec-tronics, software, and instru-mentation engineering andbrings this expertise to his newposition. Peter's dedicated andon-site presence will providetighter coupling between theEngineering Division and theALS, more integrated manage-ment of engineering resourceswithin the ALS, and a long-range focus as the ALS looks toits future as well as to the next-

generation light source. A pri-mary component of his job willbe the ALS detector program.“This program is a virtual um-brella that brings together talentfrom the ALS, Engineering, andPhysics to focus on the detectorneeds of the ALS,” stated Peter.“Detectors can be purchasedfrom manufacturers, but theunique requirements of the ALSbeamlines often require uniquedetectors which are not avail-able commercially.” This newprogram aims to help userswith existing detectors as wellas to develop novel detectorsthat will improve ALS science.As the detector program gets offthe ground, Peter also antici-pates incorporating a postdocprogram where new engineerscan be mentored and trained.This detector program antici-pates the Department of En-

ergy's Office of Basic EnergySciences (BES) detector and ac-celerator R&D initiative that isslated for FY 2008 and will en-hance Berkeley Lab's ability todo research in this area.

Sue Bailey recently joined theALS as leader of the User Serv-ices Group, which includes theUser Services Office, Commu-nications Section, and Experi-mental Setup Coordination. Shebrings to her new position over20 years of scientific, software,and managerial experience. Suealso has the perspective ofworking at two synchrotron fa-cilities, Daresbury SynchrotronRadiation Source in the UnitedKingdom and the ALS. AtDaresbury, she was the groupleader and user point of contactin the European community fora protein crystallography com-putational project and led herown research team on struc-ture-function relationships of

bacterial metalloproteins. Shealso performed research on en-zymes in the sulphur cycle andsecretion systems of pathogenicbacteria.

In 2003, Sue came to theALS for a two-year stint as abeamline scientist in the Berke-ley Center for Structural Biol-ogy. This evolved into a posi-tion as the BCSB's user supportmanager for the ALS proteincrystallography beamlines. Suereturned to England and toDaresbury, but was soon luredback to the Bay Area and theALS. “I'm pleased and honoredto again be part of this world-class facility,” she stated. “I havean open-door policy, and allusers are welcome to drop in.”Sue's office is in Building 6,Room 2212D, within the UserServices Office. You can alsocontact her by email at SBai-ley2@lbl.gov or telephone at510-486-7727.

New Faces

Peter Denes. Sue Bailey.

16

The ALS operating scheduleis divided into user beam shifts,accelerator physics/machinesetup shifts, maintenance andinstallation shifts, and vacationshutdown shifts. In a “typicalyear,” there is usually one longshutdown for major servicing,large installations, and up-grades. This long shutdown andassociated startup usually oc-curs in the spring and lastsabout six weeks. Also, in a typ-ical year the ALS schedules anddelivers more than 5000 beamhours to users. Below is a sum-mary of events during the pre-vious three fiscal years and theavailability and reliability of thefacility.

Availability is one of themost important performanceparameters of the facility. Avail-ability is defined as the ratio ofdelivered versus scheduled usertime, while reliability is definedas the ratio of the number of ac-tual fills that were completedwithout interruption versus thenumber of scheduled fills.Maintaining a high availabilityas the facility becomes moremature and complex (e.g., theaddition of new insertion de-vices, injector upgrades, feed-back and feed forward) is achallenging task.

The number of hours sched-uled and delivered is shown inthe table. In this review period,there was a deviation from thetypical yearly shutdown patternas described above. In FY06 theALS ran the entire year withouta major shutdown, and in FY07the ALS had two long-termshutdowns—one in the fall of2006 and the other in the springof 2007. Therefore, the number

of scheduled and delivered userhours were rather different inthose two years. Because of thisanomaly, it is convenient tolook at the availability over theentire three years. Of the 16,001scheduled hours, the ALS de-livered 15,253 hours, which av-erages to 5083 hours per year,with a total availability of95.3% delivered in schedule.

There was a drop in avail-ability in FY07. This was be-cause of two cascading effectsthat arose from the injector up-grade. In the fall of 2006, theALS underwent a major shut-down to install and commissioncomponents necessary for full-energy injection. At the end ofthe shutdown, there was a ma-jor failure in one of the compo-nents (the booster bend powersupply), which resulted in a lossof nine user days. The secondeffect was that this failure re-sulted in longer fill times forthe remainder of FY07.

Reliability is another impor-tant performance parameter ofthe facility, which is distinctfrom availability. Reliability isdefined as the ratio of the num-ber of actual fills that werecompleted without interruptionversus the number of scheduledfills. Providing good availabilityis necessary but not sufficient toensure good reliability. For ex-ample, a user run with manyunscheduled dropouts but fastrecovery times would result ingood availability but poor relia-bility. A good measure of relia-bility is the mean time betweenfailures (MTBF). The MTBFwas 40 hours in FY05 and in-creased to 50 hours in FY06 and51 hours in FY07.

As a national user facility, the ALS is required to report userdemographics and publication information annually to the U.S.Department of Energy. Figure 1 shows the growth in particularscientific fields and the overall user growth from 1998–2007. Thedrop-off in 2007 is attributable to the fact that there were twolong shutdowns in FY07 as opposed to just one, as in a typicalyear. The breakdown of different types of institutions that makeup our user base is shown in Figure 2. The growth of the usercommunity over the past 10 years is mirrored by the growth inbeamlines and publications, as shown in Figure 3. As the num-ber of beamlines approaches the capacity of the storage ring,new beamlines will be created by chicaning straight sectionsand revamping some of the older bend-magnet beamlines.

Accelerator Availability and Reliability

User Demographics and Publications

FACILITYUPDATES

by David Robin

HOURS SCHEDULED AND DELIVERED

Scheduledhours

Deliveredhours*

Availability Mean time betweenfailures (hours)

FY05 5600 5344 95.4% 40

FY06 6201 6045 97.5% 50

FY07 4200 3864 92.0% 51

*Does not include unscheduled hours delivered to users.

Figure 1. Bar graph showing growth in areas of science. The2007 numbers reflect the two shutdowns that occurred inFY07.

continued on page 17

The User Support Buildingproject team has been workingto minimize the impacts of thedirected funding change for theproject this fiscal year ($5M in-stead of the planned $17M). Weare moving forward with aphased-construction model and

plan to break ground during theSeptember 2008 shutdown toinstall the foundations, under-ground utilities, and major ver-tical steel columns. The six-weekshutdown, beginning on Sep-tember 2nd, was scheduled toaccommodate construction work

that is not compatible with ALSuser operations due to vibra-tions. Work on this phaseshould be completed aroundthe end of the calendar year.The next phase will begin inspring/summer 2009 and willinclude the remainder of thestructural steel and exteriorskins of the building. Thisphase be will completed aroundthe end of calendar year 2009.The final project phase will be-gin in spring/summer 2010 andinclude the entire interior of thebuilding. Depending on howearly the funding for the 2010fiscal year arrives, the projectwill be completed in either late2010 or early 2011. We are thrilledthat we are moving moving for-ward on this critical facility,

which will improve our supportfor our users.

Design work on the 57-room Berkeley Lab Guest Houseis substantially complete. Con-struction on the site began withmass excavation activities toready the building pad. Foun-dations are currently being in-stalled. We anticipate construc-tion of the relatively simplewood-framed structure to becompleted in June 2009 and theGuest House to be open forguests shortly thereafter. We arecurrently working with the UCBerkeley Residential and StudentService Program to finalize anagreement to operate the GuestHouse. Once this agreement isin place we will be able to de-termine the final room rates.

17

Construction Projects UpdateFACILITYUPDATES

0% 4%

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4%

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37%

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ALS User Institutions(2158 total users)

LBNL

Other DOE Labs

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Beamlines/Publications 1995–2007*

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Figure 2. Pie chart showing percentages of different typesof user institutions.

User Support Building.

Berkeley Lab Guest House.

Figure 3. Graph of growth in beamlines (pink) and publica-tions (blue). *Note that publications for 2007 were still beingcollected at the time this section was being written.

User Demographics and Publications continued from page 16

18

We are in the process ofsubmitting a variety of fundingrequests to DOE, ranging froma theory program, to detectordevelopment, to research on en-ergy problems, to the rebuildingof Sector 7, and more, all in an-ticipation of new programs thatCongress and the President seempoised to support in the nextfiscal year. For example, a recentDOE call for proposals spans awide range of activities, ex-

tending from single-investigatorand small-group research (SISGR)to Energy Frontier ResearchCenters (EFRCs). Funding for newawards under these programsshould be available in FY09,pending appropriations. The re-search and instrumentation areascovered include those outlinedin the Grand Science ChallengesReport of the Basic Energy Sci-ences Advisory Committee, andUse-Inspired Discovery Science, as

described in The 10 Basic Re-search Needs Workshop Reports.

The EFRCs will focus on thescientific breakthroughs neededfor advanced energy technolo-gies. Examples of research areasinclude the direct conversion ofsolar energy to electricity andchemical fuels, biological feed-stock conversion into portablefuel, and new radiation-tolerantmaterials. The SISGR grantscover areas such as ultrafast sci-ence, chemical imaging, com-plex materials research, and in-strumentation.

of 102 gold atoms surrounded by44 molecules of a thiol compound(para-mercaptobenzoic acid, or p-MBA). The central gold atoms aregrouped in a fivefold symmetricpacking arrangement known as aMarks decahedron, which is sur-rounded by additional layers of goldatoms in unanticipated geometries.The protective p-MBAs interactnot only with the gold but withone another, forming a rigid sur-face layer. This research is a suc-cess on several levels. The groupdeveloped a technique that solvesa previously unsolvable nanos-tructure. They delivered a verydetailed atomic map of this struc-ture, which itself reveals an un-usual discovery: the discretenature of the nanoparticle, whichcan be explained by the closing ofa 58-electron shell.

The ALS Moves Forward: New InitiativesFACILITYUPDATES

BES Grand Challenges Report.

Science Roundup continued from page 3

continued on page 19

5.5

0 20 40 60

(Mg1–xFex)OFit to (Mg1–xFex)O spin-unpairedFit to (Mg1–xFex)O spin-paired

Pressure (GPa)

Den

sity

(10

3 kg/

m3 )

80 100 120

5.0

4.5

4.0

Pressure dependence of the density of (Mg1 –1xFex)O (x = 0.17 and 0.2)shows an anomalous change in slope, modeled as a “mixed-state” regionwhere iron with spin-paired and spin-unpaired 3d electron configurationscoexist in the structure of magnesiowüstite.

Squeezing Iron Speziale et al., J. Geophys. Res.112, B10212 (2007)http://www-als.lbl.gov/als/science/sci_archive/166iron.htmlIt is now known that the iron pres-ent in minerals of the lower mantleof the Earth undergoes a pres-sure-induced transition with pair-ing of the spins of its 3d electrons.A team from the University ofCalifornia, Berkeley, Tel Aviv Uni-

versity, and Lawrence LivermoreNational Laboratory has used x-raydiffraction at very high pressureto investigate the effects of thistransition on the elastic propertiesof magnesiowüstite (Mg1–xFex)O,the second most abundant min-eral in the Earth's lower mantle.The new results suggest that theeffect of the spin-pairing transitionon magnesiowüstite can be largeenough to require a partial revi-sion of the most accepted model ofthe lower mantle composition.

Toward Curing Autism Araç et al., Neuron 56, 992 (2007)http://www-als.lbl.gov/als/science/sci_archive/165autism.htmlEstablishment of neural connec-tions at specialized intercellularjunctions called synapses is crit-ical for proper brain function, anderrors in the process are thought

Model for the arrangement of theneuroligin-1/neurexin-1β complex atthe synapse. Neurexins are tetheredto the pre-synaptic cell membrane(top) and neuroligins are tetheredto the post-synaptic cell membrane(bottom) by their stalk regions.Their interaction provides trans-synaptic connectivity.

continued on page 20

for all sources—insertion de-vices as well as bend and su-perbend magnets. These gainsresult from the doubling of theaverage current, smaller vertical

Top-Off continued from page 1

19

Together with users, theALS is proposing a collabora-tion involving the Berkeleycampus and Stanford called theTheory Institute for Photon Sci-ences (TIPS), which will pro-vide theoretical support to theusers of existing and futurelight source facilities in meetingthe Grand Challenges. One ofthe missions of TIPS will be to

New Initiatives continued from page 18

0 5 10 15 2023.7

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t [h]

T [o

C]

Average air temperature in the ALS accelerator tunnel for a typicalday with injection at 1.5 GeV (blue) as well as with full energy in-jection (red), showing the improved thermal stability.

Sketch of the beam current history during one day before andafter top-off.

Depiction of the COSMIC and MAESTRO beamlines on the ALSfloor at Sector 7.

Time-average current increasedby a factor of 2

Δtδt

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A)

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NanoARPES

MicroARPESCoherentImaging

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MAESTRO

COSMIC

initiate stronger interactions be-tween experimentalists and the-oreticians.

Proposals for rebuilding Sec-tor 7 of the ALS focus on theMAESTRO and COSMIC in-struments; this remains a pri-ority in our strategic plan. TheMicroscopy and Electronic Struc-ture Observatory (MAESTRO)

beam sizes, and smaller verticalgaps.

For top-off injection towork, the injector energy had tobe increased from 1.5 to 1.9 GeV.

This required an upgrade ofparts of the booster synchrotron(particularly rf components, powersupplies, diagnostics and controls)as well as an upgrade of the someof the pulsed-injection elements.With the completion of the 2006shutdown and commissioningperiod, the major hardwarework for the top-off upgradewas complete. However, althoughall the hardware installationswere completed at the end of 2006,the new power supply for thebooster dipole chain failed dur-ing the final testing conductedby the vendor. This caused sev-eral days’ delay in user startup inJanuary 2007 and subsequentlylimited performance. A success-ful collaborative effort betweenthe vendor and ALS engineersduring the Thanksgiving shut-down in November 2007 re-solved the problem.

The first beam operation ofthe booster synchrotron at up to1.9 GeV occurred on December 3,2007. During the following week,injection rates into the storagering were improved, and full-energy injection became stan-dard on December 11. Oncefull-energy injection was imple-mented, an immediate benefitbecame obvious: transients inair and cooling water tempera-tures—previously caused by thechange in magnet currents forinjection—disappeared, resultingin better stability of the accelera-

tor. The goal for summer 2008 isto slowly increase the peak storedcurrent to 500 mA. This will re-sult in an increase in averageflux and brightness even beforefull top-off operation.

Also in 2007 and 2008, a setof very extensive radiation safetystudies were performed, an im-portant activity to be completedbefore top-off operation can be-gin. Top-off operation requiresthat the beamline shutters re-main open during injection.There has been good progress,culminating in an outside peerreview of the tracking studies,demonstrating that injectionwith the safety shutters open issafe, given certain controls in-volving interlock systems andverification of all necessaryapertures. This includes the in-stallation of some new aper-tures. All additional interlocksystems and apertures neces-sary to ensure safe operation intop-off mode will have been in-stalled by the beginning of 2009.The process that leads to regu-latory approval for top-off oper-ation was started in late summer2007 and we hope to receive ap-proval in August 2008. We an-ticipate beginning initial top-offoperation on most of the beam-lines during some acceleratorphysics shifts in fall 2008 andthen begin full top-off operationfor all beamlines during usertime beginning in early 2009.

continued on page 20

to be associated with autism andother disorders. Researchers fromStanford University and the Uni-versity of Texas SouthwesternMedical Center have reported high-resolution, three-dimensional struc-tures of the proteins, called neuro-ligin-1 and neurexin-1β, that formthis connection. Because muta-

tions in the neurexin and neuroligingenes are among the multiple ge-netic causes of autism, under-standing the molecular mechanismof these proteins in synapse de-velopment is a first step towardsdevelopment of novel therapeuticsdirected to treat and possiblycure autism.

will address the need for im-provement of spatial and en-ergy resolution for photoemis-sion. Coherent Scattering andDiffraction Microscopy (COS-MIC) will provide improved, in-tense coherent light in the 0.5–3keV range with full polarizationcontrol.

We also see opportunitiesfor advances in how we gener-ate and detect photons. We havesubmitted two proposals—onefor advanced accelerator R&Dtoward a next-generation lightsource and one for advanced x-ray detector technology. Thedetector proposal is specificallytuned to the soft x-ray needs at

Science Roundup continued from page 18

20

For information about usingthe ALS, contact:

ALS User Services OfficeAdvanced Light SourceLawrence Berkeley National LaboratoryMS 6R2100Berkeley, CA 94720-8226Tel: (510) 495-2001Fax: (510) 486-4773Email: alsuser@lbl.gov

ALS home pagehttp://www-als.lbl.gov/

Editors:Lori TamuraElizabeth MoxonJulie McCulloughArthur Robinson

Design, layout, photography,and additional writing pro-vided by the Creative ServicesOffice and the Communica-tions Department of BerkeleyLab’s Public Affairs Depart-ment.

The editors gratefully ac-knowledge the ALS users andstaff for their contributions,advice, and patience.

August 2008Ernest Orlando LawrenceBerkeley National Laboratory University of California Berkeley, California, 94720-8235

This work was supported bythe Director, Office of Science, Office of Basic En-ergy Sciences, of the U.S. De-partment of Energy underContract No. DE-AC02-05CH11231. 2009MARK YOUR CALENDARS,

UPDATE YOUR BLACKBERRIES!

ALS Users’ MeetingO C T O B E R 1 5 – 1 7 , 2 0 0 9

New Initiatives continued from page 19

the ALS, with an initial empha-sis on the needs of new beam-lines such as MAESTRO andCOSMIC.

It is important to note thatalthough growth at the ALS andother national facilities has beenlimited under recent federalbudgetary restraints, new op-portunities for funding continueto arise. We strongly encourageour users and staff to bring for-ward new ideas to take advan-tage of such opportunities. Wecan provide important assis-tance in bringing such proposalsto funding agencies, foundations,etc. Partnerships among users andthe ALS can be very persuasive.