Gas Electron Multiplier (GEM) Status of the GEM/DHCAL project - - PowerPoint PPT Presentation

▶
gas electron multiplier gem
SMART_READER_LITE
LIVE PREVIEW

Gas Electron Multiplier (GEM) Status of the GEM/DHCAL project - - PowerPoint PPT Presentation

Nov 02, 2023 678 likes •890 views

1 Gas Electron Multiplier (GEM) Status of the GEM/DHCAL project Seongtae Park University of Texas at Arlington, USA LCWS12 University of Texas at Arlington, USA 22~26 October 2012 HEP/UTA LCWS12 2 Outline 1. Introduction to GEM based

slide-1
SLIDE 1

HEP/UTA

1 LCWS12

Status of the GEM/DHCAL project

Gas Electron Multiplier (GEM)

University of Texas at Arlington, USA

Seongtae Park

LCWS12 University of Texas at Arlington, USA 22~26 October 2012

slide-2
SLIDE 2

HEP/UTA

2 LCWS12

Outline

  • 1. Introduction to GEM based DHCAL
  • 2. Prototype GEM detectors

 DAQ: KPIX, DCAL

  • 3. Test results: Radiation source, Cosmic rays
  • 4. Test results: FNAL beam test
  • 5. Progress on LGEM construction

 Structure & assembly  LGEM qualification

  • 6. Summary
slide-3
SLIDE 3

HEP/UTA

3 LCWS12

DHCAL concept and GEM Detector

20 : 80 :

2 

CO Ar

R

Chamber filled with gas

Electron Avalanche  Amplification

  • GEM detector is composed of a chamber, HV supplier,

anode board, readout electronics, and DAQ program

Use Double GEM layers Steel absorber

  • Passive (material) and Active (GEM) layers
  • Increase spatial resolution (1 x 1 cm² readout pads)
slide-4
SLIDE 4

HEP/UTA

4 LCWS12

  • Flexible configurations: allows small anode pads for high

granularity

  • Robust: survives ~1012 particles/mm2 with no performance

degradations

  • Fast: based on electron collection, ~few ns rise time
  • Short recovery time  can handle high rates
  • Uses simple gas (Ar/CO2) – no long-term issues
  • Runs at relatively low HV ( ~400V across a foil)
  • Stable and robust operations

Why GEM’s for DHCAL?

slide-5
SLIDE 5

HEP/UTA

5 LCWS12

Readout system Chamber 30x30 prototype GEM chamber and Readout Electronics

  • GEM Foils(CERN)

310x310 mm2 Active area : 280x280 mm2

  • Active gas room

350x350x6 mm3  For 3/1/1 gaps KPiX readout system/SLAC

 13 bit resolution(ADC)  Designed to handle 1024 channels/chip, currently 64/chip (ver.7)

3 gain ranges

  • Normal gain
  • Low gain
  • Double gain
  • KPIX:64, DCAL:256 readout channels

64-readout pads

Pad board FE board

DCAL readout system/ANL

 1 bit resolution(ADC)  64 channels/chip

2 gain ranges

  • High gain for GEMs (10

fC~200 fC signals)

  • Low gain for RPCs (100

fC~10 pC signals)

slide-6
SLIDE 6

HEP/UTA

6 LCWS12

Some test results with 30x30 cm2 chamber/KPiX

We use an open gas system (gas flows at atmospheric pressure). Thus, pressure inside chamber is affected by the atmospheric pressure directly. This pressure change affects the chamber gain. The chamber gains were recalculated to the values at 1 atm. Effective chamber gain to HV

55Fe run result

Pressure dependence of chamber gain HV =1950V (DVGEM=390 V)

  • 244/kPa
slide-7
SLIDE 7

HEP/UTA

7 LCWS12

Highest charge Summed charge Landau fit

BG noise

Cosmic run/KPiX

19cm 19cm

8x8 cm2 Pad area

Scintillators

Charge sharing

slide-8
SLIDE 8

HEP/UTA

8 LCWS12

10cmx10cm Cosmic Trigger area

Cosmic Run/DCAL

slide-9
SLIDE 9

HEP/UTA

9 LCWS12

Radioactive Source Run/DCAL

Source: Ru-106(b-ray), 20cm elevation from the chamber window HV=-1950V(DVGEM=390V)

slide-10
SLIDE 10

HEP/UTA

10 10 LCWS12

FNAL beam test/Setup

GEM6: KPIX GEM7, GEM5, GEM4: DCAL C1,C2: 2x3 cm2  2x2 cm2 overlap C3,C4:10x10 cm2 Beams: 32GeV Muon, Pion, 120GeV Proton GEM6: Read out by 13bit KPiX designed for the ILC time line GEM7, GEM5, GEM4: Read out by 1bit DCAL chip by ANL and FNAL GIA: Medical image intensifier prototype with 12 bit ADC in-house readout Triggers formed off the motion table: 1. 10x10 coincidences for guaranteed beam penetration through the detector array 2. 2x3 coincidences arranged perpendicular to each other for 2x2 coverage in the center of the detector array 3. Coincidence of 1*2: Guaranteed beam penetration with center 2x2 coverage (efficiency ~95%)

GEM GEM7 GEM GEM6 GE GEM5 GE GEM4 C4 C4 C1 C1 C2 C2 C3 C3 GI GIA

Particle: Proton High Voltage: 1950V Energy: 120 GeV Trigger: 2x2cm2

slide-11
SLIDE 11

HEP/UTA

11 11 LCWS12

HV scan with 120 GeV Proton beam

g=~11000 @ 395V

slide-12
SLIDE 12

HEP/UTA

12 12 LCWS12

Noise subtraction and efficiency curves

Landau fit BG noise Proton(120 GeV) signal Efficiency curve

tot i i

N N  

Ni=number of hits above threshold Ntot=total number of hits

  • =

120GeV P 2x2cm2 ~95% @5fC

slide-13
SLIDE 13

HEP/UTA

13 13 LCWS12

3 DCAL GEM Chamber Event Display

Beam direction (120 GeV Protons)

Total 60 triggers accumulated GEM7 GEM4 GEM5 A single event w/ 3 coincidental hits GEM7 GEM4 GEM5

slide-14
SLIDE 14

HEP/UTA

14 14 LCWS12

GEM 7- Upstream GEM4- Downstream

  • Holes are dead channels or

suppressed noisy channels

  • 2 chamber and 3 chamber

coincidence hits show minimal fraction of events with multiple particle hits per trigger

Hits from Pion Showers

Hit multiplicity 5fC threshold(KPIX)

DCAL KPIX

Hits above 5fC were counted and normalized to 1000 Demonstrates the KPIX capability to take many hits simultaneously

slide-15
SLIDE 15

HEP/UTA

15 15 LCWS12

96x96 cm2 large GEM chamber

 CERN-UTA joint developed 32cmx96cm GEM foil Single-side etching technique

 32x96x3=9,216 readout channels/chamber

Ano node pad pad:1 :1x1 cm cm2 Steel, t=18 mm Gap=13 mm 1x1 m2 area

slide-16
SLIDE 16

HEP/UTA

16 16 LCWS12

Assembling LGEM+spacer

Locate spacer on the jig plate Gluing(Epoxy glue) Curing Cathode with spacer

Class 10,000 clean room (12’x8’)

LGEM with spacer *Spacer wall thickness=0.5mm

slide-17
SLIDE 17

HEP/UTA

17 17 LCWS12

LGEM qualification(resistance measurement)

FOIL NAME Nstrip-pass <tsaturation> Nstrip>2000s Notes LGEM1(I) 30 1790 5 Strip 9 failed Strips 17, 18, 21, 23 & 30 >2000s LGEM2(T) 31 1720 3 Strips 2, 3 & 20 > 2000s LGEM3(I) 31 1711 4 Strip 21 Rsat @ 130GOhms Strips 15, 20, 26 & 31 > 2000s LGEM4(T) 29 1549 2 Strip 17, 18 failed Strips 4 & 5 > 2000s

slide-18
SLIDE 18

HEP/UTA

18 18 LCWS12

Summary

  • 30cmx30cm GEM prototype chambers and test runs

 Construction of 4 prototype GEM chambers using 30x30cm2 GEMs  Equipped with KPIX(64ch) and DCAL(256ch) DAQ system  Test with radiation sources(Fe-55, RU-106, Cs-137 etc.), cosmic rays  FNAL beam test  Analyses of over 7M beam test events from Aug. 2011 run in progress  Continue taking cosmic ray data with these four chambers

  • 32cmx96cm unit chamber construction proceeding

 Built mobile clean room for foil certification and chamber construction  First 5 foils of 32cmx96cm delivered and qualification completed  G10 spacers delivered and assembling of spacers and LGEMs completed

  • Mechanical design of anode boards for 32cmx 96cm unit chambers being

working on with SLAC(KPIX) and ANL(DCAL)

slide-19
SLIDE 19

HEP/UTA

19 19 LCWS12

Backup

Reconstructed event animation

slide-20
SLIDE 20

HEP/UTA

20 20 LCWS12

Setup for LGEM resistance measurement

Electrometer (Keithley 6145)

ADC PC

Analog output

LGEM Equivalent circuit

6145

i iR iC R C (QC)

DV During the R measurement, 6514 is sourcing a known constant current i (1 nA). Thus, R=V (Gohm) for the Ohmic material. Saturation time >260GOhm