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Progress in Thick GEM- -like like Progress in Thick GEM (THGEM)- - - PowerPoint PPT Presentation

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Progress in Thick GEM- -like like Progress in Thick GEM (THGEM)- -based Detectors based Detectors (THGEM) R. Chechik, A. Breskin, C. Shalem, M. Cortesi & G. Guedes Weizmann institute of science, Rehovot, Israel V. Dangendorf

slide-1
SLIDE 1
  • R. Chechik et al.

SNIC @ SLAC April 2006

Progress in Thick GEM Progress in Thick GEM-

  • like

like (THGEM) (THGEM)-

  • based Detectors

based Detectors

  • R. Chechik, A. Breskin, C. Shalem, M. Cortesi

& G. Guedes Weizmann institute of science, Rehovot, Israel

  • V. Dangendorf

Physikalisch Technische Bundesanstalt, Braunschweig, Germany

  • D. Vartsky & D. Bar

SOREQ NRC, Yavne, Israel MOTIVATION: MOTIVATION: Robust, economic, large-area radiation imaging detectors FAST, HIGH-RATE, MODERATE LOCALIZATION RESOLUTION

slide-2
SLIDE 2
  • R. Chechik et al.

SNIC @ SLAC April 2006

Gaseous multiplication in holes Gaseous multiplication in holes

  • Avalanche confined within a small volume
  • Secondary effects confined/reduced -> high gains
  • True pixilated structures
  • Possibility to CASCADE multipliers -> further higher gains

Breskin, Charpak NIM108(1973)427 Discharge in glass

capillaries

Lum et al. IEEE NS27(1980)157, Avalanches

& Del Guerra et al. NIMA257(1987)609 in holes

Sakurai et al. NIMA374(1996)341, Glass Capillary plates

& Peskov et al. NIMA433(1999)492

Sauli NIMA386(1997)531 GEM

GEM

Ostling, Peskov et al, IEEE NS50(2003)809 G-10

“Capillary plates”

Chechik et al. NIMA535(2004)303

& Physics/0502131 THGEM THGEM

High electric field in the holes

103-104 e- out 1e- in

slide-3
SLIDE 3
  • R. Chechik et al.

SNIC @ SLAC April 2006

Thick GEM Thick GEM-

  • like multipliers: THGEM

like multipliers: THGEM

  • R. Chechik et al. NIM A535 (2004) 303-308

& R. Chechik et al. NIM A553 (2005) 35-40

Manufactured by standard PCB techniques of precise precise drilling drilling in G-10 (+other materials) and Cu etching Cu etching.

Hole diameter d= 0.3 - 1 mm

  • Dist. Bet. holes a= 0.7- 4 mm

Plate thickness t= 0.4 - 3 mm A small THGEM costs ~3$ /unit. With minimum order of 400$ ~120 THGEMs. ~10 times cheaper than standard GEM.

ECONOMIC & ROBUST ! ECONOMIC & ROBUST !

slide-4
SLIDE 4
  • R. Chechik et al.

SNIC @ SLAC April 2006

Is THGEM an Is THGEM an “ “Expanded Expanded” ” GEM GEM ?

?

expanded

  • The dimensions

does not scale up

  • Electron diffusion & transport
  • Electric fields
  • Gain
  • Timing properties
  • Rate capability
  • Ions transport

It is a new device that has to be studied. It is a new device that has to be studied.

THGEM Standard GEM 103 gain in single GEM 105 gain in single-THGEM Important: 0.1mm G-10 rim. reduces discharges

  • > high gains!

1mm

Cu

slide-5
SLIDE 5
  • R. Chechik et al.

SNIC @ SLAC April 2006

Edrift EHole Etrans Need to study the effect of all fields on: e e-

  • and ion transport in/out holes

and ion transport in/out holes

  • > efficiency to single-electron events
  • > cascade THGEMs
  • > ion backflow to the conversion gap

Electric fields at photocathode surface Electric fields at photocathode surface

  • > operation with solid photocathode

Gain, signal rise-time, rate capability, localization, etc

Garfield simulation of electron multiplication in Ar/CO2 (70:30)

Semi Semi-

  • transparent

transparent photocathode photocathode Reflective Reflective photocathode photocathode

Operation mechanism Operation mechanism (role of all fields)

(role of all fields)

slide-6
SLIDE 6
  • R. Chechik et al.

SNIC @ SLAC April 2006

Example: Example: Photon detector w reflective CsI PC

Photon detector w reflective CsI PC deposited on the THGEM top face deposited on the THGEM top face

(e.g. RICH photon detectors) (e.g. RICH photon detectors)

Require: • High field on the PC surface (for high QE).

  • Good e- focusing into the holes (for high detection efficiency).
  • Low sensitivity for ionizing background radiation (e.g. RICH).

e Ref PC

0.4mm thick 0.3mm holes 0.7mm pitch >3kV/cm >3kV/cm

  • 0.08
  • 0.04

0.00 0.04 0.08 10 20 30 40

Maxwell software calculation

∆VGEM= 2200V

∆VGEM= 1200V ∆VGEM= 800V

Electric field on photocathode surface

5

E [kv/cm]

Distance from center [mm] Electric field on photocathode surface Electric field on photocathode surface hole dipole field hole dipole field created by the created by the

∆VTHGEM=2200V ∆VTHGEM=1200V ∆VTHGEM=800V

∆VTHGEM=2200V ∆VTHGEM=1200V ∆VTHGEM=800V

slide-7
SLIDE 7
  • R. Chechik et al.

SNIC @ SLAC April 2006

Focusing is done by hole dipole field. Focusing is done by hole dipole field.

  • Maximum efficiency at Edrift =0.
  • Slightly reversed Edrift (50-100V/cm)

good photoelectron collection low sensitivity to MIPS !

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

0.0 0.5 1.0 1.5 2.0

Gain~103 1 Atm. Ar/CH4(95:5)

40 20 80 60 100

e- transfer efficiency [%] Edrift [kv/cm]

Relative

Photon detector w reflective Photon detector w reflective CsI CsI PC PC deposited on the THGEM top face deposited on the THGEM top face (2) (2)

e Ref PC Edrift

E E E=0

slide-8
SLIDE 8
  • R. Chechik et al.

SNIC @ SLAC April 2006

Focusing is done by hole dipole field. Focusing is done by hole dipole field.

  • Maximum efficiency at Edrift =0.
  • Slightly reversed Edrift (50-100V/cm)

good photoelectron collection low sensitivity to MIPS !

  • 0.6
  • 0.4
  • 0.2

0.0 0.2 0.4 0.6

0.0 0.5 1.0 1.5 2.0

Gain~103 1 Atm. Ar/CH4(95:5)

40 20 80 60 100

e- transfer efficiency [%] Edrift [kv/cm]

Relative

Photon detector w reflective Photon detector w reflective CsI CsI PC PC deposited on the THGEM top face deposited on the THGEM top face (2) (2)

e Ref PC Edrift

E E E=0

slide-9
SLIDE 9
  • R. Chechik et al.

SNIC @ SLAC April 2006

Single Single-

  • THGEM: e

THGEM: e-

  • transport into holes.

transport into holes. Role of Role of E Ehole

hole

  • Ref. PC

Full electron transfer efficiency into the holes, already at low Full electron transfer efficiency into the holes, already at low gain. gain.

  • > good single-electron detection efficiency
  • > good energy resolution with highly ionizing radiation

400 800 1200 1600 2000 2400

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

CF4 gain 3 CH4 gain 6 Ar/CO2 gain 20

Electron transfer efficiency

∆VTHGEM [v]

Ar/CH4 gain 30

Edrift =0

slide-10
SLIDE 10
  • R. Chechik et al.

SNIC @ SLAC April 2006

ST PC

400 800 1200 1600 2000 2400 2800 0.0 0.2 0.4 0.6 0.8 1.0 1.2 400 800 1200 1600 2000 2400 2800 0.0 0.2 0.4 0.6 0.8 1.0 1.2

Transfer efficiency

∆VTGEM (v)

gain 10 Ar/CO2(70:30) Pure CH4

Current mode Pulse counting mode

gain 100

Edrift =1kv/cm

∆V THGEM (V)

Full electron transfer efficiency into the holes, already at low Full electron transfer efficiency into the holes, already at low gain. gain.

  • > good single-electron detection efficiency
  • > good energy resolution with highly ionizing radiation

Single Single-

  • THGEM: e

THGEM: e-

  • transport into holes.

transport into holes. Role of Role of E Ehole

hole

(2) (2)

With ST PC require: Edrift ~1kV/cm

slide-11
SLIDE 11
  • R. Chechik et al.

SNIC @ SLAC April 2006

  • Gain up to 104-105 with single electrons (sparks)

Example: THGEM photon detector with reflective CsI photocathode.

Single Single-

  • THGEM: gain

THGEM: gain

  • Ref. PC
  • R. Chechik et al. NIMA553 (2005) 35-40

105

500 1000 1500 2000 2500 3000 10

  • 3

10

  • 2

10

  • 1

10 10

1

10

2

10

3

10

4

10

5

10

6

500 1000 1500 2000 2500 3000

10

  • 3

10

  • 2

10

  • 1

10 10

1

10

2

10

3

10

4

10

5

10

6

10

  • 3

10

  • 2

10

  • 1

10 10

1

10

2

10

3

10

4

10

5

10

6

10

  • 3

10

  • 1

10

1

10

3

10

5

Single THGEM

t=0.4, d=0.3, a=0.7 [mm]

  • Atm. Pressure

Ar/CO2(30%) Ar/CH4(5%) CH4 CF4

Effective Gain

∆VTHGEM [v] Similar gain w ST PC.

slide-12
SLIDE 12
  • R. Chechik et al.

SNIC @ SLAC April 2006

  • Ref. PC

Single Single-

  • THGEM: counting rate

THGEM: counting rate

10

5

10

6

10

7

10

8

10

2

10

3

10

4

10

5

10

8

Effective gain Rate [electrons / mm2 sec]

  • Signal rise time < 10ns
  • Rate capability: ~10MHz/mm2 (space charge)
slide-13
SLIDE 13
  • R. Chechik et al.

SNIC @ SLAC April 2006

Double Double-

  • THGEM: Cascaded operation

THGEM: Cascaded operation role of E role of Etrans

trans

  • C. Shalem et al. NIM A558 (2006) 475-489

Ehole > Etrans e- focused into hole Ehole < Etrans e- collected on GEM top

e-

Require: Large Etrans for good extraction from THGEM1 Small Etrans for good focus sing into THGEM2

→ Optimization

slide-14
SLIDE 14
  • R. Chechik et al.

SNIC @ SLAC April 2006

efficient transfer to the 2 efficient transfer to the 2nd

nd THGEM:

THGEM:

  • up to high Etrans (e.g. 3kV/cm).
  • at relatively low THGEM gains.

1 2 3 4 5 6 7 8 9 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

Ar/CO2(70:30) 760torr Pulse counting mode

Transfer efficiency EDrift (kv/cm)

∆VTGEM=1700V (Gain~103 )

2 4 6 8 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

∆VTGEM=1800V (Gain~104 )

2 4 6 8 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

∆VTGEM=1300V ( Gain~10 )

Etrans

Both 0.4mm thick 0.3mm holes 0.7mm pitch

Double Double-

  • THGEM: cascaded operation

THGEM: cascaded operation

Role of Role of E Etrans

trans

(2) (2)

slide-15
SLIDE 15
  • R. Chechik et al.

SNIC @ SLAC April 2006

  • Higher total gain (106-107) w single e-.
  • >103 higher gain at same ∆VTHGEM
  • Better stability

Double Double-

  • THGEM multiplier: Gain, rise time

THGEM multiplier: Gain, rise time

Fast signals, Double THGEM (t=1.6mm d=1mm, a=1.5mm).

  • Atm. Pressure Ar/30%CO2

Total gain=~ 106

10ns

  • R. Chechik et al. NIMA553 (2005) 35-40

400 800 1200 1600 2000 2400 10

  • 3

10

  • 1

10

1

10

3

10

5

10

7

double double

Ar/CO2(30%)

single

Ar/CH4(5%)

single

Effective Gain

∆VTHGEM [v]

Double & single THGEM

t=0.4, d=0.3, a=0.7 [mm]

symmetric operation

  • Atm. pressure

Symmetric operation

0.4mm thick 0.3mm holes 0.7mm pitch

Etrans=3kV/cm 107

slide-16
SLIDE 16
  • R. Chechik et al.

SNIC @ SLAC April 2006

Double Double-

  • THGEM multiplier: ion backflow

THGEM multiplier: ion backflow

e- ion ST PC ST PC Ion backflow smaller than with 4-GEM multiplier. Prolonged PC life-time.

  • C. Shalem et al. NIM A558 (2006) 475-489
slide-17
SLIDE 17
  • R. Chechik et al.

SNIC @ SLAC April 2006

2D double 2D double-

  • THGEM detector: a

THGEM detector: a flat flat imaging detector imaging detector

Radiation (gas Conversion) THGEMs 2D readout anode

. e-

Resistive anode (e.g. C paint sprayed on PCB) Simple and economic readout scheme. Induced-signal width matched to readout-pixel size.

Resistive anode:

  • Signal broadening
  • HV decoupling
  • Electronics spark protection

C paint->3 MΩ/square

  • > ~70% charge transmission

evaporated Ge-> 30 MΩ/square

  • >~95% charge transmission
slide-18
SLIDE 18
  • R. Chechik et al.

SNIC @ SLAC April 2006

10x10 cm 10x10 cm2

2 2D double

2D double-

  • THGEM detector

THGEM detector

  • 2x 10x10cm2 THGEM
  • 2-sided pad-string anode (0.5mm thick)
  • Delay-line readout (SMD)

2 mm pitch, 1.35ns/mm

front side back side X & Y DL-signals 0.4mm thick, 0.5mm Ø holes, 1mm pitch

slide-19
SLIDE 19
  • R. Chechik et al.

SNIC @ SLAC April 2006

Gain and uniformity Gain and uniformity

Flat field

5x10

3

6x10

3

7x10

3

8x10

3

2 4 6 8 10 12

+ - 10%

  • No. of points

Gain

gain unformity 25 measurement points

Energy resolution Energy resolution

100 200 300 400 500 600 700 800 900 1000 500 1000 1500 2000 2500 3000

Count C hannels

Local S pectrum F e

55 E nergy resolution = 21%

Local Local energy spectrum of 6 keV x-rays

FWHM 21%

Ar/CH4 (95:5) 8keV x-rays Conversion gap = 10 mm, 1kV/cm Transfer Gap = 2 mm, 3.5 kV/cm Induction Gap = 1 mm, 4 kV/cm ∆V THGEM=1210 Volt Gain =6x10 Gain =6x103

3

slide-20
SLIDE 20
  • R. Chechik et al.

SNIC @ SLAC April 2006

Localization : linearity, resolution Localization : linearity, resolution

5 lp/cm: 1mm wide slits, 2mm center to center 10 lp/cm: 0.5mm wide slits, 1mm center to center

0.4mm thick, 0.5mm Ø holes, 1mm pitch

Sub Sub-

  • mm resolution !

mm resolution !

2 4 6 8 10 12 0.0 0.2 0.4 0.6 0.8 1.0

Modulation

Frequency (lines pairs per cm)

Modulation transfer function

50% @ 6lp/cm

0.5mm wide slits, 1mm center to center 1mm wide slits, 2mm center to center

Gain =6x10 Gain =6x103

3

slide-21
SLIDE 21
  • R. Chechik et al.

SNIC @ SLAC April 2006

Sauli: double THGEM, Ar/CO2, 6keV x-rays,

1kHz/mm2. Stabilize ~12 hours, x2 gain rise.

  • Charging up?
  • Insulator polarization?

results from HV? Rate? total current? history?

Long Long-

  • term stability

term stability

5 10 15 20 25 2000 4000 6000 8000 10000

gain

hours

0.02kHz/mm

2 8 keV

0.2 kHz/mm

2 6 keV

Our 10x10 cm2 double THGEM detector Ar/CH4, 6 & 8 keV x-rays, low rate ~25% changes

GEM THGEM

slide-22
SLIDE 22
  • R. Chechik et al.

SNIC @ SLAC April 2006

5 10 15 20 25

10

3

10

4

Gain

hours

1900V i0=1pA [1] 1800V i0=1pA [2] 1700V i0=1pA [3]

Single THGEM

5 10 15 20 25

10

2

10

3

10

4

10

5

10

6

hours

Double THGEM ETRANS=3kV/cm

2x1400V i0=1pA [1] 2x1450V (change by +100 -50V only) [2] 2x1500V (increase 50 V only) [3]

Long Long-

  • term stability (2)

term stability (2)

ST PC

1mm

i

  • THGEMs require a few hours of stabilization.
  • Stabilization time depends on total gain/current.
  • gain variation ~ factor 2.
  • could depend on history (time after THGEM & gas introduction).
  • Measured currents w UV + ST PC.
  • Edrift=0.15kV/cm.
  • Initial flux 5x105 e-/mm2 (~1kHz/mm2 x-ray).

Could not be raised due to PC decay.

  • Possible additional effects from p, temp & HV

instability.

i

ST PC

1mm

slide-23
SLIDE 23
  • R. Chechik et al.

SNIC @ SLAC April 2006

Long Long-

  • term stability (3)

term stability (3)

5 10 15 20 25

100

Gain hours

Double THGEM ETRANS=3kV/cm

2x1400V i0=1pA [1] 2x1450V (change by +100 -50V only) [2] 2x1500V (increase 50 V only) [3]

103 104 105 106 102

0.4mm thick, 0.3mm Ø holes, 1mm pitch 0.4mm thick, 0.6mm Ø holes, 1mm pitch

  • Larger hole → shorter stabilization time. Effect of the bare insulator??
  • Evidence for combined dependence on history + total gain/current

5 10 15 20 25 10

2

10

3

10

4

10

5

gain

hours

2x1500V [1] 2x1700V [2]

Double THGEM Etrans=3kV/cm

2x1800V [3]

slide-24
SLIDE 24
  • R. Chechik et al.

SNIC @ SLAC April 2006

Planned studies Planned studies

  • 1. Systematic study on long-term stability vs. rate (with x-ray).
  • 2. Understanding the effect of the 0.1 mm rim (e.g. reduce it).
  • 3. Studying THGEMs of different materials;

e.g. CIRLEX = polyimide (Kapton).

slide-25
SLIDE 25
  • R. Chechik et al.

SNIC @ SLAC April 2006

Applications Applications

LARGE-AREA DETECTORS, ROBUST, MODERATE COST ns, sub-mm, MHz/mm2

  • Particle

Particle tracking at moderate (sub-mm) resolutions. e.g. muon-detector @LHC2.

  • TPC readout.
  • Sampling elements in calorimetry. (ILC??)
  • Readout of light from LXe detector (XENON).
  • Moderate-resolution, fast (ns) X

X-

  • ray

ray and n n imaging.

  • Single

Single-

  • photon

photon imaging. e.g. Ring Imaging Cherenkov (RICH) detectors (presently w GEMs).

advantages: robust, high eff. for single photons, low sensitivity to ionizing BG.