Download NA61_CM_PSD_Guber_oct_2012_3 - Indico

Status of the PSD
F.Guber
INR RAS, Moscow, Russia
- Status of the PSD calibration
- Improvement of the PSD stability operation
- Some remarks on the PSD electronics upgrade
- Large module beam test at T10 beam (June 2012)
NA61 Collaboration meeting, CERN, October 8-12, 2012
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PSD – Projectile Spectator Detector
Feb 2012 – the PSD was assembled completely
Central part:
16 modules
10 x 10 x 120 cm3
Outer part:
28 modules
20 x 20 x 120 cm3
Compensating calorimeter- Each module - 60 sandwiches of Pb/scintillator,
sampling ratio 4:1; 10 longitudinal sections with 10 MAPDs readout.
PSD
at 17m
13 AGeV
20AGeV
30 AGeV
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PSD calibration June 2012
PSD calibration was done with 100 GeV muons and muon beam trigger
MAPD voltages have been increased comparing with HV used in 2011.
Electronics noise was significantly reduced.
Signal spectra in small module 8
Pedestal spectra
Signal spectra in large module 20
Pedestal spectra
Straightforward method – the calibration parameter is the ratio of muon
energy deposition in the module section (~ 5 MeV) to ADC value.
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Calibration results (June 2012)
158 GeV proton energy reconstruction with all modules and with clusters
Mean values
Energy resolution
MC ~ 6.5%
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2012 PSD calibration parameter set is in SVN and SHINE
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PSD calibration Sep 2011
PSD calibration was done with 158 GeV
protons in parallel with physics run.
Calibration with muons was not possible.
Calibration parameters for each section of module have been obtained by
solving the linear system of 10 equations.
Rather complicated method, consists of a few stages, needs good
alignment of beam spot with the center of module.
Mean values
all modules
clusters
Energy resolution
MC ~ 6.5%
2011 PSD calibration parameter set is in SVN and SHINE
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Improvement of the PSD stability operation
During first week of p-Pb beam run (July 2012) a multiple cases of
PSD MBs malfunctions were observed.
Namely, MBs were silent to trigger or, inversely, some MBs
produced fake triggers.
The reason of such behavior was not understood that time.
August 2012 - About 6-7 suspicious (silent) MBs were identified.
A few of them were not responding at all.
Identified problem:
Functionality of NIM-TTL converter (comparator)
LowTTL
2.2 V
NIM
FPGA
TTL
4.5 V
It was found that silent MBs have “Low-TTL” signal level ~10% less
than normal ones.
After increase the level of signals for about 1.5 times silent MBs started
to work correctly.
Resistor dividers in ALL 44 MBs have been replaced also.
No problem with PSD stability during pPb@2012 run.
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Some remarks on the PSD electronics upgrade (I)
Readout part (PCB3)
3parts -3
boards
FPGA (memory, firmware, DAQ interf), connect.
Digital part (PCB2)
12-bit ADCs, HV-controllers
Analog part (mezzanine board PCB1)
10 integrat., control amplifier, adder for PSD trigger
PSD electronics for all 44 modules is in working condition.
Two main drawback of present PSD electronics:
-the PSD trigger signal comes after integrators with rise time ~60 ns:
too slow and has too large time-amplitude walk.
Needs careful adjustment for each beam energy.
- at present no feedback for MAPDs voltage – voltage can not be readout.
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Some remarks on the PSD electronics upgrade (II)
Proposal to replace existing PSD readout electronics on new one using DRS
is good opportunity to solve existing problems, but…
Existing PSD electronics should be replaced completely.
Total cost? Will be comparable with the cost of existing electronics!
Manpower?
Our proposal –
in spite of attractive proposal to replace PSD electronics to
new one based on DRS, to postpone this action on second stage
(do this together with new vertex detector) and not do this now.
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T10 test beam at CERN
(June 2012)
The goal - to study the PSD response at low proton energies.
Up to now the PSD response was studied at 20-158 GeV.
Important as for NA61 as another experiments-NICA,….
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Hadron calorimeter module test on T10 (June 2012)
T10 provides beams of pions,
and protons in momentum
range 2-6 GeV/c
Beam
(e+, π+, p)
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~15 m
Identification of beam protons and pions
2 Gev/c
P
3 Gev/c
4 Gev/c
π
5 Gev/c
6 Gev/c
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Time resolution ~ 50 psec.
Muons spectra in module sections
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Calibration of longitudinal sections by muon beam
2007 SPS beam - 75 GeV l.y~2ph.e/MeV- small module (10x10cm2)
2010 PS-T10 beam Em<6 GeV l.y~ 2 ph.e./MeV - small module (10x10cm2)
2012 PS-T10 beam Em<6 GeV l.y~ 2 ph.e./MeV – large module (20x20cm2)
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Sum of proton energy depositions in the PSD sections
Protons at 3 GeV/c – deposited energy in 1, 1+2, 1+2+3,… 1+…+10 sections
in 1 section
in 5 sections
Protons, 2 GeV/c,
Ep =1.2 GeV
in 9 sections
in 2 sections
in 6 sections
in module
in 3 sections
in 7 sections
in 4 sections
in 8 sections
Protons, In3green:
GeV/c
Hadron shower profile
Ep = 2.2 GeV
Protons at 6 GeV/c – deposited energy in 1, 1+2, 1+2+3,… 1+…+10 sections
in 1 section
in 2 sections
in 3 sections
in 4 sections
Practically no shower for protons 2 GeV/c
while shower is well enough developed
at 6 GeV/c.
in 5 sections
in 9 sections
in 6 sections
in module
in 7 sections
in 8 sections
Protons, In6green:
GeV/c
Hadron shower profile
Ep = 5,1 GeV
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Large PSD module response for low energy protons
The PSD response
at energy range 2 – 158 GeV
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The PSD is ready
for Dec.2012 – Jan. 2013 Be run.
Thank you !
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