What we did up to now:Summary of the measurements performed up to now with the gas setup built for the
THGEMs coated with the CsI.
• Photocurrent measurements (Leszek’s chamber) with several gas mixtures (Ne, Ar, CH4, NeCH4 X/100-X, ArCH4 X/100-X, ArCO2 70/30) at different pressures (i.e. atm pressure, 0.2 bar, 30 mbar) for a dummy THGEM coated with CsI and with a dummy THGEM as a drift (see Jarda’s presentation GDD 32 meeting);
• Quick characterization (drift and voltage scans) for a double structure THGEM (C7 type: d=0.4 mm, p=0.8 mm, t=0.4 mm, rim=0.01 mm) used as a single structure with 55Fe source flushing the gas at atmospheric pressure and with several gas mixtures (NeCH4 90/10, CF4, ArCH4 X/100-X, ArCO2 70/30);
• Optimization of the voltage on the double THGEM structure for few gas mixtures at atmospheric pressure with 55Fe source;
• Drift scan with the UV light (Oriel Lamp) on the double THGEM used as a single and as a double structure just with the Ar/CO2 gas mixture (70/30);
• Single Photon spectrum acquisition and estimation of the rate of the photons from the current measured onto the anode.
Same setup, several & different purposes
Gas mixer
Avantes – UV lamp
picoammeters
55Fe
Double Double THGEM THGEM C7C7
Leszek’s Leszek’s chamber chamber Dummy/dummyDummy/dummy
Quartz window of the double THGEM chamber (type C7)
Oriel Lamp
Three positions of the shutter: 1.completly open, 2.closed (some internal reflections),3.Open + filter 3.0 OD
N2 inlet
Hidden N2 exhaust
Setup for photocurrent measurements and optimization of performance for the double
THGEM structure with the iron source
Setu
p f
or
UV
lig
ht
meas.
wit
h
the d
ou
ble
TH
GE
M s
tru
ctu
re
Filter 0.5 Filter 0.5 ODOD
Narrow Filter
Filter 3.0 Filter 3.0 ODOD
Some examples about performed meas.
THGEM: C7d=0.4 mmpitch =0.8 mmt=0.4 mmrim=0.01 mm
drift = wires
THGEM 2THGEM 1
anode
d=4.5 mmd=1.6 mmd=1.6 mm
200 400 600 800 1000 1200 1400 1600
0
1000
2000
3000Data: CK122_BModel: Exp2PMod1 Chi^2/DoF = 1461.68412R^2 = 0.99289 a 2793.52937 ±9.03815b -0.00231 ±6.9399E-6
Cou
nts
ADC channels
Energy Spectrum
-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8
-680
-660
-640
-620
-600
-580
-560
-540
-520
-500
-480
V=1 kV, atm pressure Ar/ CO2 70/ 30;
Oriel + 0.5 OD+ narrow filter
Cu
rren
t (p
A)
Drift Field (kV/ cm)
V=1 kV V=0.9 kV
Single Photon spectrum
Collection efficiency of electron from CsI
-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0-350
-300
-250
-200
-150
-100
-50
0
50
100
150
200
250
V1=1.36 kV, V
2=1.36 kV, E
induction=3 kV/ cm, E
drift=0.67 kV/ cm;
Atm pressure Ar/ CO2 70/ 30; source 55Fe big collimator.
Cu
rren
t (p
A)
Transfer Field (kV/ cm)
Anode Current Bottom 2 Current Top 2 Current Bottom 1 Current Drift Current Top 1 projection Current
Transfer scan of the double THGEM with Iron source
