development of a thgem-based photon detector for cherenkov imaging applications silvia dalla torre...

DEVELOPMENT OF A THGEM-BASED DEVELOPMENT OF A THGEM-BASED PHOTON DETECTOR FOR PHOTON DETECTOR FOR

CHERENKOV IMAGING APPLICATIONSCHERENKOV IMAGING APPLICATIONS

Silvia Dalla TorreSilvia Dalla Torre

INFN - Trieste INFN - Trieste

On behalf of anOn behalf of an

Alessandria-CERN-Freiburg-Liberec-Prague-Torino-TriesteAlessandria-CERN-Freiburg-Liberec-Prague-Torino-Trieste

CollaborationCollaboration

TIPP09 - Tsukuba, Japan 11-17/3/2009 A THGEM-based photon detectorTIPP09 - Tsukuba, Japan 11-17/3/2009 A THGEM-based photon detector Silvia DALLA Silvia DALLA TORRETORRE

OUTLINEOUTLINE

A NEW GENERATION OF GASEOUS PHOTON DETECTORSA NEW GENERATION OF GASEOUS PHOTON DETECTORS WHY ? HOW ?

THGEM CHARACTERISATIONTHGEM CHARACTERISATION GEOMETRICAL PARAMETERS PRODUCTION ASPECTS

DETECTING SINGLE PHOTONSDETECTING SINGLE PHOTONS MULTILAYER DETECTOR SPECTRA AND GAINS TIME RESOLUTION PHOTOELECTRON EXTRACTION EFFICIENCY

CONCLUSIONSCONCLUSIONS


WHY ?WHY ?


THE ONLY ECONOMIC WAY TO COVER LARGE SURFACES THE ONLY ECONOMIC WAY TO COVER LARGE SURFACES ↔ ↔ GASEOUS PDsGASEOUS PDs

photoconverting vapours are no longer in use, a part CLEO IIIphotoconverting vapours are no longer in use, a part CLEO III (rates ! time resolution !)(rates ! time resolution !)

the present is represented by MWPC (open geometry!) with CsI the present is represented by MWPC (open geometry!) with CsI (RD26)(RD26)

the first prove (in experiments !) that coupling solid photocathodes and gaseous detectors works

Severe recovery time (~ 1 d) after detector trips ion feedback Aging after an integrated charge of a few mC/cm2 CsI ion Moderate effective gain ~ 104 bombardment

The way to the future: The way to the future: ion blocking geometriesion blocking geometries GEM/THGEM allow for multistage detectors

Good ion blocking (up to IFB at some % level) MHSP: IFB at 10-4 level (opening the way to solid photocathodes for visible light?)

First step in this direction: PHENIX HBD (not an imaging device !)

PASTPAST

PRESENT

PRESENT

FUTURE

FUTURE

HOW ?HOW ?

REQUESTS :REQUESTS :

ion blockingion blocking (moderate space) resolution (moderate space) resolution

(~1 mm)(~1 mm) good time resolution (high good time resolution (high

rate applications)rate applications) high gainhigh gain production of large surfacesproduction of large surfaces robustnessrobustness


our ANSWER :our ANSWER :

THGEM-based THGEM-based MPGDsMPGDs

• GEM derived – PCB GEM derived – PCB technologytechnology

• Proposed and explored by A. Breskin Proposed and explored by A. Breskin et al.; V. Peskov et al.et al.; V. Peskov et al.

• production: standard PCB production: standard PCB techniquestechniques

• robustrobust• large gain reportedlarge gain reported• large surface fraction large surface fraction

available for photon available for photon converter coatingconverter coating

POTENTIALLY ABLE TO MATCHPOTENTIALLY ABLE TO MATCH

ALL THE REQUESTSALL THE REQUESTS

OUTLINEOUTLINE






THGEM and SETUPTHGEM and SETUP

• Single THGEM layer in the chamber, active surface: 30 x 30 mmSingle THGEM layer in the chamber, active surface: 30 x 30 mm22;;

• Gas mixture Argon/COGas mixture Argon/CO22 (70/30) (70/30)• Sources: X-Ray (Cu – collimated source) and Sources: X-Ray (Cu – collimated source) and 5555Fe (uniform irradiation);Fe (uniform irradiation);• Two approaches: Two approaches: gaingain from from signal amplitude spectra signal amplitude spectra

and from and from current measurements current measurements (pico-ammeters with resolution (pico-ammeters with resolution ~1pA)~1pA)


7Elena Rocco - RD51 MPGD - Paris, October 2008Elena Rocco - RD51 MPGD - Paris, October 2008

SKETCH OFTHE CHAMBER

diam

pitch

rim

Picture at the microscope

bottom

To detect ionizing particle :V3< V2< V1<V0

V3

V2

V1

V0

Edrift = (V3-V2) /d1

Einduction = (V1-V0) /d2

V = V2-V1

d1

d2

Metallographic section

THGEMtop

EXAMPLES OF THGEMsEXAMPLES OF THGEMs


R3

P1

W2

P1:D=0.8 mmPitch=2 mmRim=0.04 mmThick=1mm

R3:D=0.2 mmPitch=0.5 mmRim=0.01 mmThick=0.2mm

W2:D=0.3 mmPitch=0.7 mmRim=0.1 mmThick=0.4mm

A MULTIPARAMETER SPACE TO EXPLORE !A MULTIPARAMETER SPACE TO EXPLORE !

4 geometrical parameters4 geometrical parameters: : diameter pitch rim thicknessdiameter pitch rim thickness

+ + materialmaterial + + production procedureproduction procedure

30 different T

HGEMs characterized

30 different T

HGEMs characterized

HERE:HERE:

a flavour a

bout gain, g

ain stability, ra

te

a flavour a

bout gain, g

ain stability, ra

te

capabilities and productio

n aspects

capabilities and productio

n aspects

A MULTIPARAMETER SPACE TO EXPLORE !A MULTIPARAMETER SPACE TO EXPLORE !

4 geometrical parameters4 geometrical parameters: : diameter pitch rim diameter pitch rim thicknessthickness

+ + materialmaterial + + production procedureproduction procedure

GAIN STABILITY 1/2GAIN STABILITY 1/2


9

•A factor >>2 in gain variation between the initial drop and the stabilization;•Different behaviour for THGEMs with and without (or small) rim.

0 2 4 6 8 10 12 14 16 18 20

0

2000

4000

6000

Eff

ecti

ve G

ain

Time (hours)

Std_no_rim Std_10_m Std_100_m

NameDiam (mm)

Pitch (mm)

Rim (m)

Thick (mm)

Std_no_rim 0.3 0.7 0 0.4

Std_10_μm 0.3 0.7 10 0.4

Std_100_μm 0.3 0.7 100 0.40 2 4 6

0

200

400

600

800

1000

1200

1400

1600

Eff

ecti

ve

Gain

Time (hours)

Std_no_rim Std_10_m Std_100_m

Continuously irradiated with collimated X-Ray source

Small rim

Different ΔV applied to the THGEMs, maximizing the gain for stable working conditions

zooming

GAIN STABILITY 2/2GAIN STABILITY 2/2


1010

Short time gain variation

Long time gain variation

55Fe source; uniform irradiation

irradiation at HV switch on (after ~1 day with no voltage)

100 μm rim

100 μm rim

no rim

no rim

START IRRADIATING after ~10 hours at nominal voltage

NameDiam (mm)

Pitch (mm)

Rim (m)

Thick (mm)

M1 0.4 0.8 0 0.4

C4 0.4 0.8 100 0.4

RATE CAPABILITYRATE CAPABILITY


0 20 40 60 80 100 120-200

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Cu

rren

t (p

A)

Rate (KHz)

RECALL:RECALL:120 kHz/ mm120 kHz/ mm22, 300 e- , 300 e- single photoelectron rates of single photoelectron rates of ~35 MHz/ mm~35 MHz/ mm22

120 kHz / mm120 kHz / mm22

0 20 40 60 80 100 120

2000

2500

3000

3500

4000

Einduction

=3.5 KV/ cm, Edrift

=1.5 KV/ cm

Gai

n

Rate (KHz)

Delta V=1.725 KV Delta V=1.775 KV Linear fit of Delta V=1.725 KV data Linear fit of Delta V=1.775 KV data

120 kHz / mm120 kHz / mm22

PARAMETERS:• Diameter = 0.3 mm• Pitch= 0.7 mm• Thickness = 0.4 mm• Rim = 0.1 mm• Gas: Ar/CO2 – 70/30

20%20%

PARAMETERS:• Diameter = 0.3 mm• Pitch= 0.7 mm• Thickness = 0.4 mm• Rim = 0 mm• Gas: Ar/CO2 – 70/30

PRODUCTION ASPECTSPRODUCTION ASPECTS

RIM production techniques – 5 approaches testedRIM production techniques – 5 approaches tested


Weizmann technique

CERN : etching from hole edges w/o image transfer

Double drilling

etching from hole edges w image transfer

Global etching:No photoresistive layer(proposed by ELTOS)

OUTLINEOUTLINE






MULTILAYER DETECTOR MULTILAYER DETECTOR FOR SINGLE PHOTON DETECTIONFOR SINGLE PHOTON DETECTION


30 mm

CsI coating

nocoating

anode (with pads)

driftWIRES

THGEM 2

Einduction

Etransfer2.0 mm

2.0 mm

2.0 mm

CsI

THGEM 3

THGEM 4

2.0 mm

THGEM 1

THGEM geometry:

- thickness = 0.4 mm - hole diameter = 0.4 mmpitch = 0.8 mm-rim = 10 μm

fused silca window

detector

NOTE: reflective photocathode

UV LIGHT PULSED SOURCES

1.1. Model UV LED-255 Model UV LED-255 by Seoul Optodevice Co., Ltd, Seoul, Korea (South)by Seoul Optodevice Co., Ltd, Seoul, Korea (South)

Central wavelength: 255 ± 10 nmCentral wavelength: 255 ± 10 nm Spectral line width: <20nm FWHMSpectral line width: <20nm FWHM

also called germicidal ray (disinfection) Applications: Water/Surface

purification, Laboratory testing

2.2. PLS 265-10 (pulsed LED) and PLS 265-10 (pulsed LED) and

controller controller by PicoQuant GmbH, Berlin, Germanyby PicoQuant GmbH, Berlin, Germany

600 ps long pulses600 ps long pulses up to 40 MHzup to 40 MHz


UV LED-255peak @ 258 PLS 265-10

peak @ 269

spectrophotometer measurement

220 240 260 280 300 nm

SINGLE PHOTON DETECTION:SINGLE PHOTON DETECTION:AMPLITUDE SPECTRAAMPLITUDE SPECTRA


GAIN: 104 00

-─ gain: 110 000

-─ gain: 113 000

-

stable detector bevariour at gains up to ~130 000

Ar/CH4: 40/60

SINGLE PHOTON DETECTION:SINGLE PHOTON DETECTION:TIME RESOLUTION TIME RESOLUTION


Recall:

TDC bin size: 108 pspulse width: 600 ps

No detector optimisation for time response performed so far

PHOTOELECTRON EXTRACTION PHOTOELECTRON EXTRACTION 1/61/6


fused silica window

e-

pA CsI

UV light source

0 1000 2000 3000 4000 5000 6000 700010

100

Atmosheric pressure; flushing;Leszek's chamberC

urr

ent

on t

h C

sI T

HG

EM

(pA

)

E / p (V/ cm/ bar)

Ar/ CH4 80/ 20

Ar/ CO2 70/ 30

Ne/ CH4 77/ 23

CH4

Keithley picoAmp

atmospheric pressure,reproducibility @ 1% level

E(V / cm)

ph

oto

cu

rre

nt

(pA

)

-

─ CH4

─ Ar/CH4, 66/34─ Ne/CH4, 62/38─ Ar/CO2, 70/30

10 mm

Photocurrent measurements in various gas atmospheres



Photoelectron extraction vs V and E, simulations and measurements

anode (with pads)

WIRES (V1)

CsI THGEM 1 ( top: V2, bottom: V3)

E

fused silica window

E = (V2-V1) / dV = V3 – V2

d

UV light source

E_field, sign convention <0 >0



photoelectron trajectories from a THGEM photocathode, simulation,multiplication switched off

thickness 0.6 mm, diam. 0.4 mm, pitch: 0.8 mm, ΔV = 1500 V

x cross-section y cross-section

external field above the THGEM : 0

x

y



photoelectron trajectories from a THGEM photocathode, simulation ,multiplication switched off

thickness 0.6 mm, diam. 0.4 mm, pitch: 0.8 mm, ΔV = 1500 V x

y

external field above the THGEM : - 500 V /cm:photoelectron lost (not entering the holes)

E


x

y



photoelectron trajectories from a THGEM photocathode, simulation ,multiplication switched off

thickness 0.6 mm, diam. 0.4 mm, pitch: 0.8 mm, ΔV = 1500 V x

y

external field above the THGEM : + 500 V /cm:photoelectron lost (too low field to extract them)

E


x

y



Anodic current in a THGEM detector versus the external electric field applied , a measurement

Ar/CH4: 40/60; 60/40V = 1kV1.1, 1.21.25, 1.3

1.351.5

The behaviour predicted by the simulation is confirmed!A clear suggestion to optimise the detector design

ZOOM

OUTLINEOUTLINE



DETECTING SINGLE PHOTONSDETECTING SINGLE PHOTONS MULTILAYER DETECTOR SPECTRA AND GAINS TIME RESOLUTION PHOTOELECTRON EXTRACTION




Intense R&D activity towards THGEM based photon detectorsIntense R&D activity towards THGEM based photon detectors In parallel and in close contact with Weizman, Coimbra, Bari,

ST.Etienne in the context of RD51 – the MPGD R&D Collaboration

Systematic characterization of THGEM propertiesSystematic characterization of THGEM properties Our recomandation: use no/small rim THGEMs !

Detection of single photons:Detection of single photons: Gains > 105 in electrically stable detectors with ≤10 m rim and a

4-layer structure time resolution ~ 7 ns effective photoelectron extraction possible in CH4 mixtures

NO STOPPING POINTS DETECTED, even if still a long way to goNO STOPPING POINTS DETECTED, even if still a long way to go


SPARE SLIDES SPARE SLIDES


SUMMARY 1/2SUMMARY 1/2


SUMMARY 2/2SUMMARY 2/2


development of a thgem-based photon detector for cherenkov imaging applications silvia dalla torre...

Documents

setupsingle thgem layer

1patipp09 tsukuba

economic way

bombardmentthe way

multistage detectorsgood

solid photocathodes

active surface

imaging device