development of gem-based digital hadron calorimetry andy white u.texas at arlington
DESCRIPTION
Development of GEM-based Digital Hadron Calorimetry Andy White U.Texas at Arlington (for J.Yu, J.Li, M.Sosebee, S.Habib, V.Kaushik). Outline. GEM operation/features First UTA GEM prototype - structure, electronics – results: cosmics, source Multichannel prototype - PowerPoint PPT PresentationTRANSCRIPT
Development of GEM-based
Digital Hadron Calorimetry
Andy White
U.Texas at Arlington
(for J.Yu, J.Li, M.Sosebee, S.Habib, V.Kaushik)
GEM operation/features
First UTA GEM prototype
- structure, electronics
– results: cosmics, source
Multichannel prototype
Digital hadronic module ideas
Funding, collaboration
Outline
Double GEM schematic
From S.Bachmann et al. CERN-EP/2000-151
Create ionization
Multiplication
Signal induction
From CERN-open-2000-344, A. Sharma
GEM foil etching
GEM field and multiplication
70m140m
GEM foil hole size
GEM operations and features
Simple, robust Stackable (single, double, triple) Fast – electron signal 5ns Relatively low voltage (~400V/foil) Flexible – almost any anode design Durable – no aging in extended tests Gain 102 – 106
Design for DHCAL using Triple GEM
Ground to avoid cross-talk
Embeded onboard readout
First UTA GEM Prototype- Double GEM detector constructed using 10x10 cm2 foils from CERN.
- Single 1x2 cm2 anode pad.
- Charge preamp, then voltage amp.
- Cosmic trigger, small counters, low rate!
- Signal verification: no signal with (a) trigger counters displaced from anode pad, (b) air in GEM detector.
UTA GEM-based Digital Calorimeter Prototype
Anode pad
layout
1x2 cm2 pad
UTA GEM prototype – high voltage
GEM Prototype with preamp/voltage amp
Amptek charge pre-amplifier
GEM prototype – trigger counters
Single cosmic event: upper = trigger,
lower = preamp output
UTA GEM Calorimeter prototype
GEM cosmic signal distribution with Landau fit
GEM prototype – source tests
- Cs137 source, ~1 MeV electrons
- Wall of prototype thinned to allow electrons to reach ionization region of GEM, and use of thin trigger scintillators.
- Rate much higher than cosmics!
- Used secondary output of charge amplifier to generate ADC gate.
- Study signals, noise, gain,…
GEM prototype – source tests
Source signal
Noise
Landau Distribution from Cs137 Source
Signal Amplitude (mV)
GEM/MIP Signal Size Computation
-Double GEM – applied 419V/stage -Total Ionization (C): ~93 i.p./cm
48 e-/MIP (5mm gap)-Double GEM Intrinsic Gain: G-Charge preamp sensitivity (GC) : 0.25 V/e-
-Voltage amp. X10 (GV)
-Output signal = C x G x GC x GV
-Observed ~370mV signal (mean of Landau)
G = 3100 ± 20% (need better amplifier calibration)
CERN GDD group measurements
Measured UTA GEM Gain
UTA Prototype
Multichannel prototype
- Next step: a 3 x 3 array of 1 cm2 pads.
- Allows one central pad with neighbors for cross-talk tests.
- Use a single layer board for simplicity.
- Use e.g. HELIX chip for readout.
- Anode board built, prototype being reworked.
Nine Cell GEM Prototype Readout
GEM module ideas
- Start from basic TESLA detector layout
- Try simple design with GEM “drawers” slid into slots in absorber (formed from plates and spacers).
- GEM layer ~6mm, readout layer ?mm.
- Readout – amplifier, discriminator, register per channel close to anode pad. Multilayer board with multiple ground planes.
- Working on existence proof of readout, services, module boundaries, supports, …
TESLA – HCAL Layout
DHCAL/GEM Module concepts
Use half-size modules w.r.t. TESLA design
Design concept for sensitive layer
3mm ionization
layer
DHCAL-GEM Layer structure
- GEM layer -> 6mm
- Electronics layer ~3mm
- Absorber thickness 16mm x 40 layers
-> ~ 4 interaction lengths for HCAL
- 10x10 mm2 cell size -> ~1.5 x 107 channels for DHCAL-GEM
DHCAL/GEM Module concepts
Bottom view
Side view
End view
DHCAL/GEM Module concepts
GEM layer slides into gap between absorber sheets
GEM operation in magnetic field
- Electrons drift along E-field lines which are ~radial in the overall detector frame.
- However, B-field exists in orthogonal direction.
- Forces on electron from E and B ~ equal
-> so…expect ~45 deg. drift.B
drift
E
Funding
• DoE ADR funding for year 1 completed-> Prototypes working, many simulation results (see talk by Jae Yu at this meeting)
• Request for two more subsequent years of ADR funding– First year of the two funded for ½ student
and ½ engineer/postdoc
• Equipment funds through ADR + LCRD– Allows us to contemplate construction of a
larger size GEM prototype
Collaboration
Discussions with Fermilab (Physics dept.) re support for development of:
- readout electronics (amplifier, discriminator, …)
- electronics “layer”
- GEM calorimeter stack for test beam
Agreement (June ’03) to proceed.
Conclusions
Built and operated first prototype
Cosmic and source results – gain OK
Multi-channel prototype being built
First ideas on module design
Funding in place for another year
Collaboration with Fermilab agreed.