1 Fulvio TESSAROTTO CERN, 23/04/2008 - Contribution from Trieste UPDATE ON TRIESTE LAB. ACTIVITY The...

Fulvio TESSAROTTO CERN, 23/04/2008 - Contribution from TriesteCERN, 23/04/2008 - Contribution from Trieste 11

UPDATEUPDATE ON TRIESTE ON TRIESTE LAB. ACTIVITYLAB. ACTIVITY

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

Fulvio Tessarotto


The HV power supplyThe 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


Ripple on the oscilloscopeRipple on the oscilloscope


HV – Power Supply: Ripples

HV= 2kV

HV= 4kV

Power Supply

HV cable

1nF

LEMOcableSCOPE


HV – Power Supply: Ripples

Receiving a phone call


Home-made Home-made picoamperometerpicoamperometer

Implemented scheme

CMOS Operational Amplifier: AD 8607

10 MΩ feedback resistor: VISHAY CNS020 (+- 0.02%, +- 10 ppm/ºC)

1 nF to 100 nF feedback capacitor

10 M protection resistor


The home-made The home-made picoammeterspicoammeters

Several temporary arrangements were tested for the home-made 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


CMOS Operational Amplifier: AD 8607


First tests of the set-upFirst 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


What we observed

Power Supply

Box with ThickGEM – no holes


Reading the voltmetersReading 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


THGEM prototype THGEM prototype geometrygeometry

Size of active area: 30mm x 30 mmThickness: 0.4 mmHoles diameter: 0.4 mmPitch: 0.8 mm diametersMaterial: R-1566 Panasonic(halogen free, anti CAF)Cu thickness: 35 μm


Summary tableSummary table

NameDrilling 0.4

mm Rim 1 (μm) Rim 2 (μm) rim production material

M1 Y 0 0 NO Panasonic

M2 Y 25 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



C3I Y 50 50 Etching Isola


C5 Y 10 10 Laser + Etching Panasonic

C6 Y 50 50 Laser + Etching Panasonic

C7 Y 10 10 Global Etching Panasonic

We received 10 samples per type


Documentation example Documentation example C3C3

FASE DI LAVORAZIONE

QUADROTTO ELTOS = 0.38 35/35 320 X 375MATERIALE PANASONIC R-1566 HF

STABILIZZARE INNER 140° 4 ORE

PRIMA FORATURA ( SOLO FORI DI SERVIZIO)AGGIUNGERE LA SCRITTA C3 SUL BORDO

STAMPA ESTERNI INCISIONE INDIRETTAAGGIUNGERE 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 35µINCIDERE 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


TheThe

FR4 FR4

materialmaterial


ProcedureProcedure

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


Maximum Maximum voltage in voltage in

NN22 Vmax: highest value of HV

which has been applied for more than 3 min without discharges.

V maxtype rim sample I sample II

50µm (TOP)

M5 50µm (BOTTOM) 2590 V 2400 V

no

M1 -test 1 no 2200 V 2000 V

M1 -test 2 2300 V 2120 V

50µm

C3 50µm 2050 V 1700 V

E1 -test 1 no 2600 V

E1 -test 2 no 2650 V

50µm

M4 0µm 2100 V

0µm

M4 50µm 2270 V

100µm

C4 100µm 3370 V

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

We provide negative voltage to the “top” of the THGEM


We are building a more compact set-up

Box for 4 THINGS- HV connectors will be on the back side

PCB

OEM44 voltmeter

Connectors for batteriesResistor (10Mohm)Capacitor (10nF)OA - AD8607Guarding “ring”Connectors for OEM44 voltmeter


Test of analog r/o chainTest of analog r/o chain

Single photon signals are generated by a picosecond laser providing ~20 ps long pulses and a correlated timing signalLaser 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


Single photon amplitude spectra from Single photon amplitude spectra from MAPMTMAPMT

825 V

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850 V

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875 V

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900 V

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925 V

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THGEM test THGEM test chamberchamber


Very first spectrum of THGEM Very first spectrum of THGEM signals from Fe source seen signals from Fe source seen

in TSin TS

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