ATLAS Zero Degree Calorimeters
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Transcript of ATLAS Zero Degree Calorimeters
ATLAS Zero Degree Calorimeters
LOI submitted to LHCC by ATLAS collaboration
1 module built and tested in NA SPS beamline
Funds in hand for construction of remaining modules
Operation by end of ‘07 feasible
Fwd workshop – January 2007Sebastian White, Brookhaven Lab
ZDC in ATLASA Zero Degree Calorimeter (ZDC) is a calorimeter that resides at the junction where the two beam pipes of the LHC become one – at 0° from the pp collisions. It is housed in the shielding unit that protects the S.C magnets from radiation, and measures neutral particle production at 0°. It can play many roles.
Outline• ZDC Physics• Installation scenario• ZDC design• ATLAS TDAQ integration• ZDC performance (simulation, rad damage,
testbeam)• Integration with Machine, LHCf• Planning
Reaction plane
x
z
y
z
Spectator neutrons•measure centrality,•Min_min_bias trigger
Beam-Beam Counter Mult/1000(Calorimeter@<2mr.)
Event characterization using forward detectors
>>Direction and magnitude of impact parameter, b
Magnitude from complementary parameters
Nparticipant=2*A-Nspectator
di-jet photoproduction-> parton distributions,x2by with momentum fraction, x14pt
2/s=x1*x2<y>~ -1/2*ln(x1/x2)Signature: rapidity gap in direction(FCAL veto)
x1
x2
Analogous upc interactions and gap structure
diffractive Non-diffractive
Probing small x structure in the Nucleus with N->jets, in Ultraperipheral Collisions(UPC)
ATLAS coverage to||<5 units. Pt ~2 Gev“rapidity gap” threshold
Rates and Kinematics
Event yields from a 1 monthHI (Pb-Pb) run at nominalLuminosity (4 1026 cm-2s-1).Counts per bin of pt=2 GeVx2/x2=+/- 0.25
(with M. Strikman and R. Vogt)
ZDC in pp( Phase II configuration)ZDC in pp( Phase II configuration)
In pp, the ZDC can measure forward production cross sections for several types of particles at very high energies. This will be useful for adjusting parameters for simulations and models, and for cosmic ray physics where the energy in one proton’s rest frame is 1017 eV – a very interesting energy for extended air showers.
What happens when a high energy proton hits the upper atmosphere?
The ZDC can find a pi0 in the midst of several neutrons.
(1M Pythia events analyzed by a ZDC)
RHIC ZDC as an accelerator tool (in pp)
PHENIX horizontal vernier scan Feb. 12, 2003
y = 0.7003x
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2
Beam displacement (mm)
SMD Readings(mm)
•Van derMeer scan (ZDC coincidence ratevs. relative beam position)•ZDC (lower curve) bkg free over 4 orders of magnitude
•ZDC also measures beam displacement (red points)•Useful for crossing anglecommissioning
Phasing with LHCf run
Phase I
Phase II
EMCal Module design(1 module only)
Light collected fromStrips of 1.5 mm quartzTransverse to beam(main energy and timing)
And 1 mm quartz rodsProjective to beam
Latter measure coordinateOf showers.
Strip detail and airLightguide
648 1.5 mm diameter rods
Provides main energy and Timing measurement
Hadronic module with Coordinate readout( 1 module per arm)
Rods are grouped into4 per readout pixel
Inserting coord readout fibers
Summary of ZDC module parameters
Energy resolution for Photons and neutrons (GEANT simulation)
Coordinate resolution for photons and neutrons
ZDC L1 trigger
• The ZDC trigger will be used primarily as a 2-arm coincidence (each arm above a preset threshold) in Heavy ion runs
• Trigger bits assigned in Central trigger Processor board ctp_cal
• Ctp_cal is designed to accept calib triggers as well as trigger from small systems like the ZDC
Aperture limitations from upstream components of the machine
Background (PYTHIA / GEANT-FLUKA simulation)
Sources of signal and Background
Interaction Point
Decays in Flight
“Walls”
Background (PYTHIA / GEANT-FLUKA simulation)
Sources of Signal and Background
Interaction Point
Decays in Flight
“Walls”
Simulation of kinematic acceptance
~1.8 Grad
~100 Mrad~10 Mrad
~1 Mrad
~100 krad
~10 krad
~100 Mrad~10 Mrad
~1 krad
PMT
Beam
800
180290
150180
30 150100 30
1000150 150150 15090
Ion
iza
tio
n c
ha
mb
er
PMT PMTTAN slot
PMT
MAPMT
MAPMT
Absorbed dose (rad/yr) in TAN at luminosity 1033 cm-2sec-1
We exposed quartz rods at the BNL linac Isotope Producer facility
At 5 Grad absorbed doseLight loss corresponds to A 30% deterioration in Resolution of coord measurement
Test beam exposure in SPS North area parasitic with RP (Oct. ‘06)
Single module exposed to 230 GeV proton beam
Spectra with 0, 10 and 20 cm steel blocks inserted in the beam
Comparison to simulation (note same energy scale used in all Simulations)
Beam tuned to enrich positron componentPeak used to confirm light yield and agreementWith simulations
Tested correlation between coordinate measurement and Position of 2 mm high beam scintillation counters
Summary of cables to USA15
What we are planning
• Install full (8 module) ZDC phased with the LHCf run plan
• Integrate ZDC into ATLAS DAQ and provide a level1 trigger
• Will remove ZDC for highest Luminosity pp runs• Provide a critical role in Heavy Ion program• Important measurements of forward particle
production in pp collisions over full acceptance permitted by TAN constraints
• Funding from US Nuclear Physics program
Schedule
• 1st module completed and tested in beam-no design changes planned
• Construction of mechanical modules can begin 2/07 expect completion in 6/07
• Remaining cables installed this spring• Main schedule uncertainty is daq electronics• Operation possible at end of ‘07 in conjunction
with LCHf detector
Extra slides
ZDC time, space and energy resolution (Average over active area)
Photon energy resolution
ZDC response to neutrons
Neutron energy resolution
Photon space resolution
Neutron spaceresolution
Neutron time resolution
The ZDC scenarios and cables
USA1532 ch
3 +3 ch
32 ch
3 +3 ch
BeamBeam
PHASE I70+6(tr) chs
PMT
Ionizationchamber
PMTPMT
LHCfHad. mod.32+1 chs
Had. mod.1 chs
Had. mod.1 chs
PMT
Ionizationchamber
PMT PMT
LHCf
Had. mod.32+1 chs
Had. mod.1 chs
Had. mod.1 chs
PMTPMT PMT
32 chUSA15
32 ch
4+4 ch
96 ch
4+4 ch
BeamBeam
PHASE II168+8(tr) chs
Ionizationchamber
PMTPMT PMT
EM mod.1 chs
Had. mod.32+1 chs
Had. mod.1 chs
Had. mod.1 chs
Ionizationchamber
PMT PMT
EM mod.96+1 chs
Had. mod.32+1 chs
Had. mod.1 chs
Had. mod.1 chs
Equipment location
• In tunnel at 140 m– 8 ZDC modules– 8 XP3292B Quartz
window PMT’s– 10 Multi anode PMT’s– 138 preamp/driver
chips(5 w total power)– 2 Led driver modules
for monitor system– Patch panels
• In USA15 – Patch panels– 3 VME crates(~300w
power consumption)– PMT HV supplies– Low voltage for
tunnel (5v, 10W)– Trigger signal cable
to LVL-1(USA15)
ATLAS ZDC Schedule
• Draft LOI circulated to ATLAS forward and Heavy Ion Working groups + LHCf - 2/06
• ZDC design completed- 4/06• Radiation Damage studies at BNL - 6/06• 1st module completed -8/06• CERN beam test- 10/06• Presentation to LHCC- ?• Module production completed - 5/07• Ready to install- 7/07
Conclusion
• ATLAS ZDC has unique capability for Heavy Ion as well as pp and beam tuning due to coordinate readout
• Preparation for beam test at CERN and radiation exposure at BNL.
• Have prepared full project file (down to WBS level 4- 150 items)
• Installation of Phase I by summer of ‘07 depending on approval
backup
ZDC Project file (p.1) including Phase II eqpt and labor costs
Concept for remote module replacement
600
965
Absorber
ZDC-modules
Cables
Left/RightUp/Down
Cables
965
Left/Right
760
100180
980
180 150 150
94190
520
9450
BackgroundMARS15:Radiation in TAN, LHCf & ZDC – N.Mokhov TAN Integration – CERN, Mar.10, 2006
Installation• Install in TAN coordinated by LEA/TS(Tsesmelis
group)• Many common issues
– Cabling,lift fixtures– Material activation
• Surveying not critical (~1mm tolerances)• We assume we are responsible for cost of cables,
panels , installation• Have requested Phase I installation ~7/07 (like
CMS) + 4 weeks of checkout• LEA aware of request and considered possible
Installation(II)
• Phase II configuration after LHCf reaches limit (L~1028-1029) for run
• ZDC design rad hard through L=1033, after that will remove for pp runs
• Heavy Ion rad dose negligible.• We are requesting approval from the
collaboration to proceed with LOI submission to LHCC (this is a critical step before we can proceed with installation)
di-jet photoproduction-> parton distributions,x2by with momentum fraction, x14pt
2/s=x1*x2<y>~ -1/2*ln(x1/x2)Signature: rapidity gap in direction(FCAL veto) and leading neutron from beam fragments
Probing small x structure in the Nucleus with N->jets, heavy flavor.
ZDC role in Heavy Ion Physics (event tag for hard photoproduction)
Leading Particle in peripheral collisions
-> ZDC tag in Heavy Ions analogous to Roman Pot tag in pp
ZDC cable detail
top view ofassembled holder
material - copper4 peace with grooves1 peace w/o grooves
1.12.1
1 2.16 6 6 11 11 6 6 6 5.55.5
3 3
6
4
75
250
X-Y rod holder
Assembling module: installing X-Y rods
Bare module
Rod is put in module and measured
Rod is removed, cut to size and replaced
All rods installed
Rod is put in module and measured
Rod is removed, cut to size and replaced