UPDATE ON TRIESTE
LAB. ACTIVITY
Fulvio Tessarotto
The set-up to measure currents
THGEM prototypes from ELTOS
First measurements on 4 pieces
Chamber for prototype test
The set-up to measure signals
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
1
The HV power supply
We used for this measurement one channel of the
CAEN N471A power supply, reading the voltage from
the LED display ( +- 1 V ) and the current from the
“current monitor” output (5 mV offset, 1 mV/nA)
We checked the stability of the power supply by looking
at signals on the HV output, using a HV cable, a 1 nF
capacitor and Le Croy oscilloscope
Typical ripple has ~ 30 μs period, 80 mV pp at HV=4kV,
the ripple amplitude being roughly linear with voltage
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
2
Ripple on the oscilloscope
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Contribution from Trieste
Fulvio TESSAROTTO
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HV – Power Supply:
Ripples
HV= 2kV
Power
Supply
LEMOcable
HV cable
SCOPE
1nF
HV= 4kV
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
4
HV – Power Supply:
Ripples
Receiving a phone call
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Contribution from Trieste
Fulvio TESSAROTTO
5
Home-made picoamperometer
Implemented scheme
1 nF to 100 nF
feedback capacitor
10 MΩ feedback resistor: VISHAY
CNS020 (+- 0.02%, +- 10 ppm/ºC)
CMOS Operational
Amplifier: AD 8607
10 M protection resistor
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
6
The home-made picoammeters
Several temporary arrangements were tested for the homemade picoamperometers, using solderless breadboard, micro
pcb on ceramic insulators and customly designed pcb’s for
home-made picomaperometers
- When powered by batteries they work fine at HV (tested up
to 8kV), with stable offsets <10 pA
- Using a battery + resistor current source of ~60 pA we
checked that the reading was correct at few pA level; the
ultimate resolution is still to be determined
At ground, the agreement between Keithley measurements
and home-made picoammeters values is roughly 1pA
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
7
CMOS Operational
Amplifier: AD 8607
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
8
First tests of the set-up
1) PS – cable1 – PA – cable2
Oscillations with amplitudes proportional to L x V (cable
length x PS voltage; no oscillations with PS off).
2) PS – cable1 – PA1 – cable2 – THGEM – cable3 – PA2
Oscillations are the same on PA1 and PA2
Decision: redundancy, shortest possible cables,
design final set-up but start measurements before it is ready
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
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Fulvio TESSAROTTO
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Fulvio TESSAROTTO
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What we observed
Box with ThickGEM – no holes
Power
Supply
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Fulvio TESSAROTTO
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Fulvio TESSAROTTO
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Reading the voltmeters
We decided to register picoammeter redings by saving pictures
of the displays
CANON Camera programmed to shoot every 2 seconds: this
allows registering measurements and all intermediate
operations done by humans
From picture analysis the images on LED displays are
translated into numbers (~ 40000 pictures so far)
This solution avoids electrical connections to the acquisition
system
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
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Contribution from Trieste
Fulvio TESSAROTTO
15
THGEM prototype geometry
Size of active area: 30mm x 30 mm
Thickness: 0.4 mm
Holes diameter: 0.4 mm
Pitch: 0.8 mm diameters
Material: R-1566 Panasonic
(halogen free, anti CAF)
Cu thickness: 35 μm
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
16
Summary table
We received 10 samples per type
Nam
eDrilling 0.4 mm
Rim 1 (μm)
Rim 2 (μm)
rim production
material
M1
Y
0
0
NO
Panasonic
M2
Y
25
0
Drilling
Panasonic
M3
Y
50
0
Drilling
Panasonic
M4
Y
100
0
Drilling
Panasonic
M5
Y
50
50
Two Sides Drilling
Panasonic
R
NO
NO
NO
NO
Panasonic
RI
NO
NO
NO
NO
Isola
C1
Y
10
10
Etching
Panasonic
C2
Y
25
25
Etching
Panasonic
C3
Y
50
50
Etching
Panasonic
C3I
Y
50
50
Etching
Isola
C4
Y
100
100
Etching
Panasonic
C5
Y
10
10
Laser + Etching
Panasonic
C6
Y
50
50
Laser + Etching
Panasonic
C7
Y
10
10
Global Etching
Panasonic
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
17
Documentation example C3
FASE DI LAVORAZIONE
QUADROTTO ELTOS = 0.38 35/35 320 X 375
MATERIALE PANASONIC R-1566 HF
STABILIZZARE INNER 140° 4 ORE
PRIMA FORATURA ( SOLO FORI DI SERVIZIO)
AGGIUNGERE LA SCRITTA C3 SUL BORDO
STAMPA ESTERNI INCISIONE INDIRETTA
AGGIUNGERE LA SCRITTA C3 SUI CS
SECONDA GALVANICA ( SOLO STAGNO )
STRIPPAGGIO RISTON
INCISIONE AMONIACALE RAME 35µ
NON STRIPPARE STAGNO
FORATURA PASSANTE ( DIAMETRO 0.4 )
INCISIONE AMONIACALE RAME 35µ
INCIDERE USANDO LA VELOCITA ADEGUATA
IN MODO DA CREARE UN ISOLAMENTO DI 50µ
INTORNO ALLA CORONA DEL FORO
STRIPPARE STAGNO
SCONTORNATURA
LAVAGGIO CIRCUITI AD ULTRASUONI IN ACQUA DEMINERALIZZATA
IMBALLO E SPEDIZIONE
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
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The
FR4
material
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Fulvio TESSAROTTO
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Fulvio TESSAROTTO
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Fulvio TESSAROTTO
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Fulvio TESSAROTTO
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Procedure
THGEM prototypes are kept under vacuum before and after
measurement
Handling is done with polyethylene gloves only
Mounting at the centre of the test box, soldering cables and
screwing nylon screws on ~5 cm nylon columns: ~ 10 min
HV provided to “TOP” of THGEM prototype, “BOTTOM” at
ground (some field above while no field below THGEM)
Flushing with N2 at ~20 l/h for more than 3 hours before
switching HV on
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
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Fulvio TESSAROTTO
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Contribution from Trieste
Fulvio TESSAROTTO
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Maximum
voltage in N2
Vmax: highest value of HV
which has been applied
for more than 3 min
without discharges.
V max
type
rim
50µm
M5
sample I
(TOP)
50µm (BOTTOM)
2590 V
2400 V
2200 V
2000 V
2300 V
2120 V
2050 V
1700 V
no
M1 -test 1
M1
no
-test 2
50µm
We provide negative voltage
to the “top” of the THGEM
C3
Preliminary conclusions:
C3 seems to be the worst (50 μm)
C4 seems to be the best (100 μm)
E1 and M5 are very good
M1 and M4 are similar
Reversing M4 rim makes a
difference
E1
-test 1
no
2600 V
E1
-test 2
no
2650 V
CERN, 23/04/2008
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sample II
50µm
50µm
M4
0µm
2100 V
0µm
M4
Contribution from Trieste
C4
50µm
100µm
100µm
2270 V
Fulvio TESSAROTTO
3370 V
29
We are building a more compact set-up
OEM44 voltmeter
Box for 4 THINGS
- HV connectors will be on the back side
PCB
Connectors for batteries
Resistor (10Mohm)
Capacitor (10nF)
OA - AD8607
Guarding “ring”
voltmeter
CERN, 23/04/2008Connectors- for OEM44
Contribution
from Trieste
Fulvio TESSAROTTO
30
Test of analog r/o chain
 Single photon signals are generated by a picosecond laser
providing ~20 ps long pulses and a correlated timing signal
Laser amplitudes are reduced by geometric selection and laser
tune down to a probability of 95% no photon pulses.
 One pixel of a Hamamtsu R7600-03-M16 MAPMT is used to
provide signal to our analog r/o chain through a resistive divider
(reducing the signal by a factor 4).
The ORTEC 142 preamp coupled to the ORTEC 450 amplifier
and the CAEN N957 was used to collect amplitude spectra
 a rough calibration was performed for several gain factors,
showing evidence of non linearities for large signals: only
signals in the linear range have been used
 Spectra were taken at various gains and combined in a single
plot to increase the dynamic range of the measurement
CERN, 23/04/2008
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Contribution from Trieste
Fulvio TESSAROTTO
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Single photon amplitude spectra from MAPMT
4000
2500
3000
3500
825 V
2000
850 V
875 V
2500
3000
2000
counts
counts
1500
counts
2500
1500
2000
1000
500
1500
1000
1000
500
500
0
0
0
1
2
3
V out from preamp
4
5
0
0
1
2
3
V out preamp
1
5
2V out preamp 3
4
5
3000
3500
900 V
950 V
4000
3000
2500
925 V
3500
2500
3000
2000
2000
2000
counts
2500
counts
counts
0
4
1500
1500
1500
1000
1000
500
500
1000
500
V out from preamplifier
0
0
1
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2
0
3
-
4
V out from preamplifier
3
05
1
2
Contribution
from Trieste
4
05
Fulvio
0
TESSAROTTO
1
2
3
V out of preamplifier
32 4
THGEM test
chamber
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Contribution from Trieste
Fulvio TESSAROTTO
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Very first spectrum of THGEM
signals from Fe source seen in TS
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Fulvio TESSAROTTO
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