Transcript HERMES Lead Glass for SHMS Electromagnetic Calorimeter ► Introduction ► HERMES Calorimeter

HERMES Lead Glass for SHMS
Electromagnetic Calorimeter
►
►
►
►
►
►
Introduction
HERMES Calorimeter
Present status
Proposed R&D works
Timeline for construction
Summary
( Arthur Mkrtchyan, YerPhI )
Hall C Meeting, January 18-19, 2008
Introduction
• At forward angles and high momentum
settings of the SHMS the electromagnetic
calorimeter will play dominant role to
separate electrons from hadrons.
• In combination with Gas Cerenkov,
Aerogel or/and TRD calorimeter will
provide a π/e rejection by factor of ~100.
• Higher energy leads to larger probability
for fluctuations of the energy deposited in
a total-adsorption calorimeter.
• It was necessary to consider a shower
counter for the SHMS thicker than is used
in the HMS (to exclude possible energy
leaks).
Introduction
• Optimization studies of the calorimeter for
the SHMS were completed in May 2007
• Our studies allowed to select an
alternative calorimeter geometry
maintained the good energy resolution
and pion rejection capabilities.
• Basic requirement for SHMS Calorimeter
was effective area ~1.5 m2 and resolution
~6% at 1 GeV
Block Diagram and sensitive areas
of SHMS Detectors
Three versions for SHMS
Calorimeter
3)
1)
2)
1. The blocks are oriented transversely, with PMTs looking
sideways. Need: 130 blocks 10x10x70 cm3 (TF-1).
2. The blocks are oriented longitudinally, with PMTs looking
upstream. Need: 182 blocks 10x10x50 cm3 or
224 blocks 9x9x50 cm3 (TF-1 & F-101).
3. The blocks are oriented transversely in PRESHOWER and
longitudinally in SHOWER. Need: 26 blocks 10x10x70 cm3
in PRESHOWER, and 224 blocks 9x9x50 cm3 (SHOWER.
Resolution and π/e rejection
• The Energy resolutions with and without
Preshower are similar: σ/E=3.67+0.92/√E.
• π/e rejection ~2x10-2. Preshower improves
rejection at least by factor 4 (open symbols).
Present Status
• Best choice for calorimeter: Preshower + Shower
- Effective area: 120 x 130 cm2
- Energy resolution: ~6%/√E
- π/e rejection at least 0.01 (at P>1 GeV/c)
• Detector Components:
- Preshower: 26 blocks from SOS Calorimeter
(TF-1 type LG, 10x10x70 cm3)
- Shower: 224 blocks from DESY-HERMES
(F-101 type LG, 9x9x50cm3)
HERMES Calorimeter
Calorimeter consisted of 840 radiation resistant
F-101 lead glass blocks arranged in a two wall
configuration, above and below beam.
Each wall was composed of 420 identical leadglass blocks stacked in a 42 x10 array.
Blocks dimentions are 9x9x50 cm3
Transmittance for 8.9 cm thick F-101
(HERMES blocks at start)
- An accumulated dose of ~ 2 krad produces
a degradation of transmittance less than 1%.
-The F-101 LG is 10-50 times less sensitive
to radiation damage than TF-1 and SF2
Energy deposition in adjacent blocks
(HERMES calorimeter)
• The position 0 cm and 9 cm correspond to the left
and right block respectively.
• Solid squares: left block; open squares right block;
stars: sum of two blocks.
Energy resolution σ(E)/E
(HERMES Calorimeter)
The line shows the parameterization
Hermes blocks possible damage
• Calorimeter was installed ~14 years ago. For
many blocks mylar may have optical contact with
blocks, which will reduce resolution
• We know that for some of HERMES moduls the
optical joint between PMT-block need to be repaire
• Blocks in the layers close to the beam plane
expected to have essential radiation dose.
• From HERMES logbook we found information
about gain degradation for some of PMT’s.
Timeline for upcoming works
(Tests and Design)
• General revision of HERMES blocks
 March-May’08
• Study of Quantum Efficiency on 5-7
randomly selected PMT’s from
HERMES calorimeter  MayJune’08
• Study of Quantum Efficiency for
new XP3461. Comparison with
HERMES PMT’s July-Aug’08
Timeline for upcoming works
(Tests and Design)
- Study of attenuation length on ~10
blocks from HERMES calorimeter.
August-September 2008
- Repair all damaged modules
October-December 2008
- Revison and selection of blocks
from SOS Calorimeter for
PRESHOWERJanuary-March’09
- Test all the modules with LED and
cosmic  April-September 2009
Plan for construction and Installation
• Preshower part exict and will be taken
out from SOS when SOS will be retired.
(Expect 2009).
• Shower blocks from HERMES calorimeter
are packed, will be shipped to JLab and we
expected to arive in February 2008.
• All hardware work is scheduled to be
completed before end of 2009.
• Design of support structure for SHMS
Calorimeter: 2009-2010
SOS (HMS) Calorimeter Support
SHMS Calorimeter may have similar supports
“hanging” from the back wall of detector hut
Plan for construction and Installation
• Develop read-out system and electronic
diagram for SHMS Calo, finalize and order
all electronic  2009-2010
• HV and slow control system  2009-2010
• Develop software for calorimeter ADC
readout and DAQ 2009-2010
• Test all calorimeter with electronic and
DAQ (Test-Lab)  2010-2011
• Be ready for installation in Hall C  2011
Summary
•
•
•
•
•
•
•
•
Based on MC studies the final version for the SHMS
calorimeter has been selected.
Energy resolution: σ<~5% at 1 GeV.
/e rejection factor without PRESHOWER: ~2x10-2.
Preshower will improve pion-electron rejection at
least by factor 4.
The use of radiation hard F-101 lead glass from
HERMES is the optimal solution for SHOWER part.
We will use TF-1 type blocks from SOS shower
detector to built PRESHOWER part for SHMS.
No significant degradation is observed for the
HMS and SOS calorimeters since 1995.
SHMS detector hut of similar quality as for HMS will
minimize calorimeter radiation degradation.
Summary
•
Final assembly of calorimeter modules will be
completed in 2009. Test with cosmic will be started.
•
Test of the calorimeter with full electronics and DAQ
is planed for 2009-2010.
•
Calorimeter will be ready for installation by end of
2010
•
We will develop software & slow control system for
SHMS similar to HMS/SOS calorimeters. (2009-2010).
•
The Yerevan Collaboration will take responsibility
for the design, construction and assembly of SHMS
calorimeter, its calibration and online software.
Everything can be ready well before shutdown of
accelerator (2013).
•