Portuguese groups at ISOLDE - CERNPortuguese groups at ISOLDE - CERN

Ulrich WahlUlrich Wahl

Instituto Tecnológico e Nuclear (ITN) SacavémInstituto Tecnológico e Nuclear (ITN) Sacavém

Centro de Física Nuclear da Universidade de Lisboa (CFNUL)Centro de Física Nuclear da Universidade de Lisboa (CFNUL)

ISOLDE and Nuclear Solid State PhysicsISOLDE and Nuclear Solid State Physics

Portuguese experiments at ISOLDE: Portuguese experiments at ISOLDE: history, people, collaborationshistory, people, collaborations

Examples:Examples:- position-sensitive electron detector development - position-sensitive electron detector development - emission channeling lattice location of Fe in Si- emission channeling lattice location of Fe in Si- PAC investigation of O and F in High-Tc Hg-1201- PAC investigation of O and F in High-Tc Hg-1201

Conclusions amd outlookConclusions amd outlook

The ISOLDE on-line isotope separatorThe ISOLDE on-line isotope separator

Ge

Sn

Pb

Pm Ho

Cu As

Sb

Bi

Sm Er

Zn Se

Te

Po

Eu Tm

Ga Br

I

At

Gd Yb

Kr

Xe

Rn

Tb Lu

Al

C N O F

Cl

Ne

Ar

He

Sc MnTi V

B

Si P S

FeCr Co Ni

Zr Nb RuMo RhTc

Ta

Th Pa U Np PuAmCmBk Cf Es FmMdNo Lr

OsW Ir PtRe

Pd Cd In

Au

Ce

Hg

Pr

Tl

Nd Dy

Y

La Hf

Ac

Ag

Li Be

MgNa

K Ca

Rb Sr

Cs Ba

Fr Ra

surfaceionization-

+plasmadischarge

Hot

Coldlaser

selectiveionization

Available beams:Available beams:~ 600 isotopes of~ 600 isotopes of

~ 70 elements~ 70 elements

1 GeV1 GeVprotonsprotons

radioactive ion beamsradioactive ion beams

massmassseparationseparation

60 keV60 keVaccelerationacceleration

target andtarget andion sourceion source

Weak Interaction andNuclear Physics

46%

Solid State Physics22%

Particle and Astro-Physics

13%

Biology/Medicine5%

Atomic Physics15%

ISOLDE ISOLDE ExperimentsExperiments

20032003

37 Experiments

300 Users96 Institutes22 Countries375 8h-shifts of radioactive

beams

Experiments involving Portuguese groups:Experiments involving Portuguese groups:typically around 10-12 shifts per yeartypically around 10-12 shifts per year i.e. ~3% of ISOLDE availability i.e. ~3% of ISOLDE availability

Semiconductor Spectroscopysensitive to chemical nature or electronic properties

(some require radioactive istopes )

106

108

1010

1012

1014

1016

1018

1020

106

108

1010

1012

1014

1016

1018

1020

defe

ct c

once

ntra

tion

(cm

)-3

NMR

EC

Channel.

Hall

DLTS PL

ENDOR

EPR

-NMR

NMR-ON

PAC,ME

EXAFS

Experimental techniques used with radioactive isotopes at ISOLDEExperimental techniques used with radioactive isotopes at ISOLDE

Portuguese groups:Portuguese groups:emission channeling (EC)emission channeling (EC)perturbed angular correlation (PAC)perturbed angular correlation (PAC)

2000 IS390 Studies of colossal magnetoresistive oxides with radioactive isotopes ~2005 spokesperson V. Amaral (U Aveiro)

1998 IS368 Lattice location of transition metals and rare earths in semiconductors

~2006 spokesperson U. Wahl (ITN & CFNUL, then IKS Leuven)

1997 IS360 Studies of high-Tc superconductors with radioactive isotopes

~2006 spokesperson J.G. Correia (ITN & CFNUL)

1986 e- PAC at ISOLDE IS01/13 spokesperson J.C.Soares

1994 Test of new PAC probes IS-P66 spokesperson J.G. Correia

e- PAC

197mHg, 73Ge, 127Cs, 80Br

2001 New improved electron emission channeling pad detectors and

development of self-triggering front-end electronics

Cooperation agreement between ITN, CFNUL and CERN EP-ATT Group (now: PH-TA1)

History of e- PAC and EC at ISOLDE-CERN

Network of groups involvedNetwork of groups involved

CFNUL LisbonCFNUL Lisbon

Prof. José C. SoaresProf. Manuel. R. Silva

2 PhD students:Elisabete Rita

Ana C. Marques1 Diploma student:

Sonia Dias

Dr. J. Guilherme CorreiaDr. Ulrich Wahl

Dr. Heinz Haas (retired)

ITN SacavémITN Sacavém

University of AveiroUniversity of Aveiro

Prof. Vitor AmaralDr. Mario S. Reis1 PhD student:

Armandina Lopes1 Diploma student:

João C. Amaral

University of PortoUniversity of Porto

Prof. J. Pedro Araújo1 Masters student:Tania Mendonça

KU LeuvenKU Leuven(Belgium)(Belgium)

Prof. André Vantomme2 PhD students:

Bart De VriesStefan Decoster

LEUVEN

Univ. ofUniv. of Kwazulu Natal Kwazulu Natal(South Africa)(South Africa)

Prof. Krish Bharuth-Ram

University of GöttingenUniversity of Göttingen(Germany)(Germany)

Prof. Hans Hofsäss(future collaboration)

CERNCERN

Dr. Peter Weilhammer(detector development)

Funding: mainly from national sourcesFunding: mainly from national sources

CFNUL LisbonCFNUL Lisbon

Portuguese Foundation for Science & Technology(dedicated CERN project on PAC & emission channeling)

ITN SacavémITN Sacavém

University of AveiroUniversity of Aveiro

University of PortoUniversity of Porto

KU LeuvenKU Leuven(Belgium)(Belgium)

Fund for Scientific Research - Flanders(dedicated project

on emission channeling)

Univ. ofUniv. of Kwazulu Natal Kwazulu Natal(South Africa)(South Africa)

University of GöttingenUniversity of Göttingen(Germany)(Germany)

Federal Ministry of Education and Research

(dedicated project on emission channeling)

CERNCERNPortuguese Foundation

for Science & Technology(dedicated CERN project on

magnetic oxides)

2 1 0 -1 -2

10

5

0

-5

-10

2 1 0 -1 -2

10

5

0

-5

-10

+ M2:- M2 :

cn te rclwclo ckw

3.85E 3 -- 4E3

3.7E 3 -- 3.85E3

3.55E 3 -- 3.7E3

3.4E 3 -- 3.55E3

3.25E 3 -- 3.4E3

3.1E 3 -- 3.25E3

2.95E 3 -- 3.1E3

2.8E 3 -- 2.95E3

the plo t sh ows th e crystal a s

it is viewn fro m the detecto r

+ z:

- z:

+ M 1:

"on-line" display: template C:\ORIGIN\PADSPEC4.OTP read with script file C:\ORIGIN\CHANRED4.SCR

Co nve rsion elect ron emissio n ch an ne lin g with 30 mm x 30 mm Si p ad 4 d ete cto r:

- M 1:

rel.

Z-c

oor

din

ate

[m

m]

rel. M 1-angle [deg]

counts raw data

0 10 20 30 40 50 60 70 800

100

200

300

nois

e

52 keV

42 keV

12 keV

coun

ts

energy [keV]

ROI

0 10 20 30 40 50 60 70 800

100

200

300

nois

e

52 keV

42 keV

12 keV

coun

ts

energy [keV]

ROI

2 1 0 -1 -2

10

5

0

-5

-10

2 1 0 -1 -2

10

5

0

-5

-10

+ M2:- M2 :

cn te rclwclo ckw

3.37E 3 -- 3.45E3

3.29E 3 -- 3.37E3

3.21E 3 -- 3.29E3

3.12E 3 -- 3.21E3

3.04E 3 -- 3.12E3

2.96E 3 -- 3.04E3

2.88E 3 -- 2.96E3

2.8E 3 -- 2.88E3

the plo t sh ows th e crystal a s

it is viewn fro m the detecto r

+ z:

- z:

+ M 1:

"on-line" display: template C:\ORIGIN\PADSPEC4.OTP read with script file C:\ORIGIN\CHANRED4.SCR

Co nve rsion elect ron emissio n ch an ne lin g with 30 mm x 30 mm Si p ad 4 d ete cto r:

- M 1:

rel.

Z-c

oor

din

ate

[m

m]

rel. M 1-angle [deg]

counts raw data

[-1102][0001]

Arsenicoccupiesmultiple

sites in ZnO

Collaboration:ITN, CFNUL

& CERN PH-TA1 group

Future detectors:pads self-triggering

5 keV trigger 10 kHz readout

Cooled 2oC

Position-sensitive Si pad detectors for Emission Position-sensitive Si pad detectors for Emission ChannelingChanneling

7373As in ZnO low electron energy As in ZnO low electron energy

Lattice site changes of implanted Lattice site changes of implanted 5959Fe in SiFe in Si

U. Wahl U. Wahl et al.et al., accepted by Phys. Rev. B, accepted by Phys. Rev. B

Fe is gettered by at least two types of vacancy-like defectsFe is gettered by at least two types of vacancy-like defects

Following release to interstitial state re-gettering occurs at a different Following release to interstitial state re-gettering occurs at a different gettering center on ideal substitutional sitesgettering center on ideal substitutional sites

as-implanted:as-implanted:

mainly displaced mainly displaced substitutional Fesubstitutional Fe

-2

-1

0

1

2-2 -1 0 1 2

experiment-2 -1 0 1 2

1.23 - 1.27 1.19 - 1.23 1.15 - 1.19 1.11 - 1.15 1.07 - 1.11 1.03 - 1.07 0.99 - 1.03 0.95 - 0.99

simulation best fit

<111>

-2

-1

0

1

2 1.18 - 1.21 1.15 - 1.18 1.12 - 1.15 1.09 - 1.12 1.05 - 1.09 1.02 - 1.05 0.99 - 1.02 0.96 - 0.99

<100>

-2

-1

0

1

2 1.10 - 1.12 1.08 - 1.10 1.06 - 1.08 1.05 - 1.06 1.03 - 1.05 1.01 - 1.03 0.99 - 1.01 0.97 - 0.99

<110>

[deg]-2 -1 0 1 2

-2

-1

0

1

2

-2 -1 0 1 2

<211> 1.15 - 1.18 1.12 - 1.15 1.10 - 1.12 1.07 - 1.10 1.04 - 1.07 1.01 - 1.04 0.99 - 1.01 0.96 - 0.99

annealedannealed at T=300°C:at T=300°C:

mainly tetrahedral mainly tetrahedral interstitial Feinterstitial Fe

-2

-1

0

1

-2 -1 0 1 2experiment

-2 -1 0 1 2

1.56 - 1.66 1.46 - 1.56 1.37 - 1.46 1.27 - 1.37 1.17 - 1.27 1.08 - 1.17 0.98 - 1.08 0.88 - 0.98

simulation best fit

<111>

-2

-1

0

1

2 1.41 - 1.48 1.34 - 1.41 1.27 - 1.34 1.21 - 1.27 1.14 - 1.21 1.07 - 1.14 1.00 - 1.07 0.93 - 1.00

<100>

-2

-1

0

1

2 1.10 - 1.13 1.08 - 1.10 1.05 - 1.08 1.02 - 1.05 0.99 - 1.02 0.97 - 0.99 0.94 - 0.97 0.91 - 0.94

<110>

[deg]-2 -1 0 1 2

-2

-1

0

1

2

-2 -1 0 1 2

<211> 1.14 - 1.18 1.11 - 1.14 1.07 - 1.11 1.04 - 1.07 1.00 - 1.04 0.97 - 1.00 0.94 - 0.97 0.90 - 0.94

-2

-1

0

1

2

-2 -1 0 1 2experiment

-2 -1 0 1 2

1.84 - 1.97 1.71 - 1.84 1.57 - 1.71 1.44 - 1.57 1.31 - 1.44 1.18 - 1.31 1.04 - 1.18 0.91 - 1.04

simulation best fit

<111>

-2

-1

0

1

2 1.53 - 1.62 1.45 - 1.53 1.36 - 1.45 1.27 - 1.36 1.18 - 1.27 1.10 - 1.18 1.01 - 1.10 0.92 - 1.01

<100>

-2

-1

0

1

2

1.47 - 1.55 1.40 - 1.47 1.32 - 1.40 1.25 - 1.32 1.17 - 1.25 1.10 - 1.17 1.02 - 1.10 0.95 - 1.02

<110>

[deg]-2 -1 0 1 2

-2

-1

0

1

2

-2 -1 0 1 2

<211> 1.35 - 1.41 1.29 - 1.35 1.24 - 1.29 1.18 - 1.24 1.12 - 1.18 1.06 - 1.12 1.01 - 1.06 0.95 - 1.01

annealed at T=800°C:annealed at T=800°C:

mainly ideal mainly ideal substitutional Fesubstitutional Fe

Oxygen & Fluorine Configurations in Hg1201 Oxygen & Fluorine Configurations in Hg1201

(High-Tc)(High-Tc)

HgBa2CuO

4+

Tc > 92K

frequency

start stop

I Q

I

Ii

Q

1

IfIf

Q.Vzz

clock

time

Radioactive

ions

O(2)

Cu O(1)

Ba

Hg

PAC

PAC

PACExperiment

Electric Field Gradient

dopant configuration fingerprint

~ 0.20

0 2500 5000 (Mrad/s)

0

50

100

~ 0.0

0

50

100

000 2500 5000

(Mrad/s)

0.34 (a)

EFG Simulations

J.G. Correia J.G. Correia et al.et al., submited to Phys. Rev. B, submited to Phys. Rev. B

Currently and near future (till ~2006):Currently and near future (till ~2006):

IS368: Lattice location in semiconductors, e.g.IS368: Lattice location in semiconductors, e.g.

Si, Ge, SiGe, diamond, Si, Ge, SiGe, diamond, III-V, nitrides, II-VI, ZnO…III-V, nitrides, II-VI, ZnO…electrical doping, transition metals,electrical doping, transition metals,rare earths,rare earths,diluted magnetic semiconductorsdiluted magnetic semiconductors

IS360: PAC in High-Tc superconductorsIS360: PAC in High-Tc superconductors

IS390: Magnetism in manganites (CMR)IS390: Magnetism in manganites (CMR)

Conclusions and outlook:Conclusions and outlook:

After 2006: New emission channeling proposal(s) applying…After 2006: New emission channeling proposal(s) applying…

new position-sensitive detectors (self-triggering pad, CCD)new position-sensitive detectors (self-triggering pad, CCD)

- on-line experiments with short-lived isotopes- on-line experiments with short-lived isotopes- low energy electron emitters (Auger electrons?)- low energy electron emitters (Auger electrons?)

a new variety of elements (e.g. Mg, Co, Ni, Zn, Ge)a new variety of elements (e.g. Mg, Co, Ni, Zn, Ge) will be available for emission channeling will be available for emission channeling