1 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste FIRST LOOK AT THGEM IN TRIESTE LAB. 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

2 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste The 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

3 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste Ripple on the oscilloscope

4 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste HV – Power Supply: Ripples HV= 2kV HV= 4kV Power Supply HV cable 1nF ?? LEMOcable SCOPE

5 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste HV – Power Supply: Ripples Receiving a phone call

6 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste Home-made picoamperometer Implemented scheme CMOS Operational Amplifier: AD MΩ feedback resistor: VISHAY CNS020 ( %, ppm/ºC) 1 nF to 100 nF feedback capacitor 10 M protection resistor

7 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste The home-made picoammeters 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

8 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste CMOS Operational Amplifier: AD 8607

9 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste What we observed Power Supply Box with ThickGEM – no holes

10 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste 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

11 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

12 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

13 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

14 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste 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 (~ pictures so far) This solution avoids electrical connections to the acquisition system

15 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

16 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste 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 batteries Resistor (10Mohm) Capacitor (10nF) OA - AD8607 Guarding “ring” Connectors for OEM44 voltmeter

17 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste 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

18 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste Summary table Nam eDrilling 0.4 mmRim 1 (μm)Rim 2 (μm)rim productionmaterial M1Y00NOPanasonic M2Y250DrillingPanasonic M3Y500DrillingPanasonic M4Y1000DrillingPanasonic M5Y50 Two Sides DrillingPanasonic RNO Panasonic RINO Isola C1Y10 EtchingPanasonic C2Y25 EtchingPanasonic C3Y50 EtchingPanasonic C3IY50 EtchingIsola C4Y100 EtchingPanasonic C5Y10 Laser + EtchingPanasonic C6Y50 Laser + EtchingPanasonic C7Y10 Global EtchingPanasonic We received 10 samples per type

19 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste Documentation example C3

20 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste The FR4 material

21 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

22 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

23 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

24 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

25 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste 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) One day flushing with N2 at ~20 l/h before switching HV on

26 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste Results from the first THGEMS

27 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

28 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

29 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

30 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

31 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

32 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

33 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste Maximum voltage reached defing V max as the highest value of HV which has been applied for more than 1 min without discharges we would obtain: Sample Vmax M M C E1 2550

34 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste THGEM test chamber

35 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste

36 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste 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 R 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

37 Fulvio TESSAROTTO CERN, 20/03/ GDD Meeting - Contribution from Trieste Single photon amplitude spectra from MAPMT