Discussion with LHCC RefereesDiscussion with LHCC RefereesNovember 18, 2008November 18, 2008
Memo sent to LHCC by LHCfMemo sent to LHCC by LHCfAnswers to Michelangelo’s questionsAnswers to Michelangelo’s questionsOpen point left from the previous Open point left from the previous
meetings with refereesmeetings with refereesWinter activitiesWinter activities
LHCf Memo: Main pointsLHCf Memo: Main points1. Our plan for the 2008/2009 winter shutdown is to continue working, focusing the
activities mainly on the DAQ software and analysis programs. We do not plan to remove the detectors from the TAN during this shutdown, but we will adapt them to the Remote Handling System.
2. As is clearly stated in the LHCf TDR, our experiment has been designed to take data at 14 TeV center of mass energy, at low luminosity (<1031 cm-2 s-1).
3. If it happens that the luminosity will exceed this limit during 5+5 TeV operation in 2009, then LHCf will have to be removed from the TAN to avoid excessive radiation damage.
4. We are extremely interested in the 7+7 TeV running since only then can we completely fulfill our physics task, which was approved by LHCC.
5. If the LHCf has been removed during 2009 operation because the luminosity has exceeded 1031 cm-2 s-1, we strongly hope to have the possibility to re-install LHCf in the TAN region during the 2009/2010 winter shutdown, and then complete our physics program early in 2010 (in the commissioning phase of the 7+7 TeV running).
6. We therefore kindly ask to the LHCC to investigate this possibility, and we strongly hope that the committee will reconfirm our original request, described in the TDR, for a LHCf data taking period at 7+7 TeV.
Answers to Michelangelo’s Answers to Michelangelo’s questionsquestions
1. Is there a chance that with the current detectors you can take data already in 2009, regardless of the energy, and still preserve their functionaility for a final run at the highest energy in 2010? Could this be achieved by simply allowing for their removal after some integrated luminosity? I would find it really odd that you give up data taking in 09 simply because the energy is not at the highest value and you want to wait until that is available.
We completely agree with your opinions. It is very necessary to take data in 2009, and will try again the data taking at the highest energy in 2010.
2. Is there a value in taking data at 10 TeV? 10 TeV instead of 14 should reduce only by a factor of 2 the equivalent CR energy at which you will be probing the production properties (E_CR ~ E^2/mp). Is a factor of 2 gain in energy so critical in the tuning of the MCs that you are willing to postpone by 1 year the possible analysis of data?
Yes, there is a strong value in taking data at 10 TeV. It is our unexpected good chance to get data at different energies. It will bring us not only important results on the energy dependence, but on the reliability of the results. Moreover, from the scientific point of view, we may expect CGC (Color Glass Condensation), a new hint to supress very low-x gluons recently discussed for HERA data among hadron theorists, that may link to composition measurement in UHECRs.
They are discussing that it would be more important at LHC energy. We think they may appear also in LHCf as increasing energy, maybe near 14TeV. This is also a good motivation for taking data also at 10TeV as a reference (and also 450 GeV!).
Composition Composition fromfrom
Auger Auger
Xmax favors heavy primary
Anisotropy favors light primary (if we trust in the AGN correlation)
4
E>5.7.10E>5.7.101919 eV eV
3. If indeed taking data in 2009 caused the detectors to fry and not be usable any longer in 2010 at the highest energy, is it conceivable to rebuild them?
We are planning to remove the detector during the high luminosity run. If it will not be possible, we are preparing to replace the plastic scintillators and the scintillating fiber belts, which might be damaged by a radiation dose greater than 10K rad.
Open points left from the Open points left from the previous previous
meetings with refereesmeetings with refereesMain point: Main point:
What happens to the spectra if we trigger on the What happens to the spectra if we trigger on the Double Arm Coincidence (for background rejection)?Double Arm Coincidence (for background rejection)?
We certainly expect that the We certainly expect that the and and 00 spectra will spectra will change.change.
We are studying by simulation how the spectra will beWe are studying by simulation how the spectra will beaffected.affected.
We hope to have some results in the first months of We hope to have some results in the first months of 20092009
Winter activitiesWinter activities
Timing measurements for silicon Timing measurements for silicon Done Done Baking out of the paint in the TAN will not be doneBaking out of the paint in the TAN will not be done
– We will not remove the detectors from the TANWe will not remove the detectors from the TAN Remote Handling System (RHS) will be installedRemote Handling System (RHS) will be installed
– We will modify the LHCf handling system to comply with We will modify the LHCf handling system to comply with the RHSthe RHS
– We are producing safety boxes to be installed above LHCf We are producing safety boxes to be installed above LHCf to avoid damages to the detectorsto avoid damages to the detectors
• We will install the protection boxes before the end of 2008We will install the protection boxes before the end of 2008
Improvements of the DAQ and analysis softwareImprovements of the DAQ and analysis software– Improvement of the online analyzerImprovement of the online analyzer– Improvement of the full data analysis flow (from DAQ to Improvement of the full data analysis flow (from DAQ to
storage)storage)– Alignment studiesAlignment studies– Improve cluster finding on silicon partImprove cluster finding on silicon part
Cross check of MC (EPICS based) simulation with Cross check of MC (EPICS based) simulation with Fluka codeFluka code
Most important slides from the Most important slides from the last LHCC presentationlast LHCC presentation
InstallationInstallation
Final installation was completed in January Final installation was completed in January 20082008
No major problems have been found No major problems have been found – Quartz fiber for laser calibration has been re-Quartz fiber for laser calibration has been re-
installedinstalled
Both Arm1 and Arm2 are working fineBoth Arm1 and Arm2 are working fine No additional noise is found in the detectors, No additional noise is found in the detectors,
despite 200 m long power lines and signal despite 200 m long power lines and signal cables (for the scintillators)cables (for the scintillators)
Front CounterFront Counter
2 fixed Front Counters 2 fixed Front Counters were installed in front were installed in front of Arm1 and Arm2of Arm1 and Arm2
They will not move They will not move with Arm1 and Arm2with Arm1 and Arm2
They are segmented They are segmented in 2 x and 2 y slicesin 2 x and 2 y slices
Very useful to check Very useful to check the beam quality and the beam quality and hence decide to move hence decide to move Arm1 and Arm2 in the Arm1 and Arm2 in the operating position operating position from the ‘garage’ from the ‘garage’ positionposition
After the installation….After the installation….
After the installation was completed, a lot of work After the installation was completed, a lot of work on:on:– DAQDAQ
• New VME board to increase DAQ rate up to > 1 KHzNew VME board to increase DAQ rate up to > 1 KHz• Integration of all the subsystem (Using MIDAS frame)Integration of all the subsystem (Using MIDAS frame)• Analyzer to check the data quality and online monitorAnalyzer to check the data quality and online monitor
– Slow control software to control and monitor:Slow control software to control and monitor:• Power suppliesPower supplies• ManipulatorManipulator• Temperature monitorTemperature monitor
– LHC interface LHC interface • New NIM style board (CIBU) to send ‘PERMIT’ to LHC (KILL the New NIM style board (CIBU) to send ‘PERMIT’ to LHC (KILL the
beam in case of high rate)beam in case of high rate)• Handhshaking software signals (DIP standard) for Injection, Handhshaking software signals (DIP standard) for Injection,
Adjust and Beam DumpAdjust and Beam Dump• LHCf Physics information (beam position, rate, background LHCf Physics information (beam position, rate, background
etc.)etc.)
Synchronization with AtlasSynchronization with Atlas To have the possibility to identify the events To have the possibility to identify the events
common with Atlas we implemented a common with Atlas we implemented a synchronization method based on the L1A signal synchronization method based on the L1A signal generated by Atlas. generated by Atlas.
We receive Atlas L1A and we store the time We receive Atlas L1A and we store the time stamp of this signal in our DAQ system.stamp of this signal in our DAQ system.
We can really correlate the Atlas events with the We can really correlate the Atlas events with the LHCf ones!LHCf ones!
Atlas Bunch ID – LHCf Bunch IdAtlas Bunch ID – LHCf Bunch Id
00 mass reconstruction mass reconstruction
(MeV)
Prelim
inary!!!!
250 250 00 events triggered (in a quite big background) and on disk events triggered (in a quite big background) and on disk
Main problems: Main problems: – low photon energy (low photon energy (≥≥ 20 20
GeV) GeV) – Direct protons in the towersDirect protons in the towers– Multi hits in the same towerMulti hits in the same tower
m m ~ 8 MeV~ 8 MeVm/m m/m ~ 6%~ 6%
ARM1 Position resolutionARM1 Position resolution
σx[m
m]
σy[m
m]
Nu
mb
er
of
even
tN
um
ber
of
even
t
x-pos[mm]
y-pos[mm]
200 GeV electrons
xx=172=172 mm
yy=159 =159 mm
E[GeV]
E[GeV]
ARM2 Position ARM2 Position ResolutionResolution
Position Resolution X Side
0
20
40
60
80
100
120
0 50 100 150 200 250
Energy (GeV)
Re
so
luti
on
(m
icro
ns
)
Data
Simulation Spread Out
xx=40 =40 mm
x-pos[mm]
y-pos[mm]
200 GeV electrons
yy=64 =64 mm
Position Resolution Y Side
0
20
40
60
80
100
120
140
160
0 50 100 150 200 250
Energy (GeV)
Re
so
luti
on
(m
icro
ns
)
Data
Simulation Spread Out
Alignment has been taken into accountAlignment has been taken into account
Preparation for data takingPreparation for data taking
FurnituresFurnituresTelephonesTelephonesAir conditionerAir conditionerNetworkNetworkComputersComputersPrintersPrinters…………
The LHCf control room has been prepared and fully The LHCf control room has been prepared and fully
equipped in the Atlas areaequipped in the Atlas area
Dummy eventDummy event
Communications with LHCCommunications with LHC
Experimental status (On/Off, Gain, etc.)Experimental status (On/Off, Gain, etc.) Detector position (Garage/Operating, position in mm, etc.) Detector position (Garage/Operating, position in mm, etc.)
Luminosity rate (Single and Double Arm)Luminosity rate (Single and Double Arm)– Front Counter rate (single Arm, double Arm coincidence)Front Counter rate (single Arm, double Arm coincidence)– Small tower rate (single Arm)Small tower rate (single Arm)– Big tower rate (single Arm)Big tower rate (single Arm)– Double Arm coincidence rate (FC.AND.Towers in opposite Double Arm coincidence rate (FC.AND.Towers in opposite
sides)sides)
Horizontal and Vertical position of the Beam (every 10000 Horizontal and Vertical position of the Beam (every 10000 events or in the whole RUN)events or in the whole RUN)
Injection InhibitInjection Inhibit Handshaking signals (Injection, Adjust, Beam Dump)Handshaking signals (Injection, Adjust, Beam Dump)
LHCf sends signals to LHC through the DIP system.LHCf sends signals to LHC through the DIP system.Link have been tested and it works fine!Link have been tested and it works fine!
Important for machine tuning! Important for machine tuning!
We are ready for data takingWe are ready for data taking On September 10 we observed some signals on On September 10 we observed some signals on
Front Counters, with Arm1 and Arm2 in garage Front Counters, with Arm1 and Arm2 in garage position for safety reasonsposition for safety reasons– That day the Atlas BPTX signal was still not That day the Atlas BPTX signal was still not
available (no info on the real bunches in the available (no info on the real bunches in the Atlas zone)Atlas zone)
On September 11 Atlas gave us the synchronized On September 11 Atlas gave us the synchronized BPTX signals, and we could take Front Counter BPTX signals, and we could take Front Counter data by using this signal (still in garage position)data by using this signal (still in garage position)
We are measuring Beam-Gas from the Beam2 on We are measuring Beam-Gas from the Beam2 on Arm1 sideArm1 side
Front Counter signalsFront Counter signals
