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THGEM: TRIESTE LAB. EQUIPMENT AND CONTACTS WITH POSSIBLE PRODUCER. Fulvio Tessarotto. Introduction THGEM prototypes from ELTOS Equipping the Trieste Laboratory Test boxes Home made amperometers. Introduction. The development of MPGD-based photon detectors is considered to be
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THGEM:TRIESTE LAB. EQUIPMENT AND CONTACTS WITH POSSIBLE PRODUCER Fulvio Tessarotto Introduction THGEM prototypes from ELTOS Equipping the Trieste Laboratory Test boxes Home made amperometers Fulvio TESSAROTTO
Introduction The development of MPGD-based photon detectors is considered to be very important by Trieste, Turin and others in the COMPASS RICH group We believe there is a brilliant future for gaseous PD’s To start with, THGEM have been selected for this investigation First studies in 2007: Elena Rocco in MPGD lab at CERN Elena’s activity will continue for 2008, and will be complemented by some work at Trieste home laboratory Fulvio TESSAROTTO
Introduction The aim of this presentation is to give informations about two items: First contacts with a possible THGEM producer Activity to equip our laboratory in Trieste for THGEM tests People involved for 2008: Jaroslav Polak (PHD, ~100%) Gabriele Giacomini (postdoc, ~100%) Giorgio Menon (~50%) Fulvio Tessarotto (~50%) We plan to provide updates whenever meaningful Fulvio TESSAROTTO
Production of THGEM prototypes Following indications from Rui de Oliveira we contacted an Italian producer: ELTOS S.p.A. (Arezzo, Tuscany) http://www.eltos.it/en/main/en-main.htm They have wide experience in production of pcb’s of all kinds ~90 workers, high tech equipments We noticed: modern work organization willingness to produce special pieces understanding of our goals Fulvio TESSAROTTO
Production of THGEM prototypes Small diameter holes need high rotation speed of the driller: the multi-spindle machines at ELTOS can reach 180000 turns/min, allowing hole diameters as narrow as 150 μm. Nominal drilling tolerance: +- 10 μm • POSALUX ULTRASPEED 6000LZ6-spindle-roboter Estimated cost for large number of holes: ~ 1 euro per 1000 holes Fulvio TESSAROTTO
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 Fulvio TESSAROTTO
THGEM prototypes we ordered • We ordered 6 identical pieces for each prototype group, • 2 groups without holes for reference measurements and • 13 groups with different production characteristics: • Single drilling, no etching • Double drilling: 0.4 mm + 0.45 mm diam. on one side only • Double drilling: 0.4 mm + 0.50 mm • Double drilling: 0.4 mm + 0.60 mm • Triple drilling 0.4 mm + 0.50 mm + 0.50 mm on the other side too • Drilling + etching 0.010 mm • Drilling + etching 0.025 mm • Drilling + etching 0.050 mm • Same as 8) with different material (Isola PLC370 HR) • Drilling + etching 0.100 mm • Drilling + laser photolytic imaging + etching 0.010 mm • Drilling + laser photolytic imaging + etching 0.050 mm • Drilling + global etching (no protection) 0.010 mm Fulvio TESSAROTTO
Summary table Fulvio TESSAROTTO
THGEM test box Fulvio TESSAROTTO
THGEM test box Fulvio TESSAROTTO
THGEM test box Fulvio TESSAROTTO
Signal amplitude spectra • Signals formed on the anode will be read out by ORTEC preamplifier 142PC and Research amplifier ORTEC 450. • The preamp has noise from 300 e- at 0 pF to 450 e- at 100 pF, rise time of 25 ns at 0 pF to 150 ns at 100 pF • The preamp sensitivity is 6.5 V/pC • The amplifier has adjustable gain from 2.5 to 3000, shaping time ~1μs • We will use a 55Fe source at start, Ar-CO2 70% - 30% (1 bar) • Gains between 10 and 10000 should provide signal amplitudes in the range from 0.2 fC to 200 fC Fulvio TESSAROTTO
Multichannel analyzer • Amplified signals will be digitized by CAEN N957 multichannel analyzer. • 13 bit ADC, 800 ns conversion time, internal buffer for 65535 signals • computer controlled via C++ libreries, 30 Mb/s USB2 transfer rate Fulvio TESSAROTTO
Anodic current measurement • For anodic current we will use a KEITHLEY 6485 picommeter (with 10 fA resolution in the lowest range, up to 1000 readings per sec and drivers for control and data storage (LabVIEW, C++, …) • Should not be used above 42 V Fulvio TESSAROTTO
Home-made Feedback amperometer Scheme of principle 10 MΩ feedback resistor (+ parallel capacitor) CMOS Operational Amplifier: AD 8607 OEM44 Voltmeter: 4.5 digits This device has been tested to operate at high voltage, powered by batteries. We plan to use one of these for each voltage line • The cost of the pieces for this device is in the order of 100 euros We are considering alternatives which would allow automatic recording Fulvio TESSAROTTO
Estimate of resolution of the home-made amperometer Using a current generator: 3V battery + 50 GΩ resistor we checked the Keithley response: 61.43 pA +- 0.23 pA Providing the same current to the home-made amperometer we obtained: 61.8 pA +- 2.7 pA In both cases no special shielding was provided => We hope to provide < 10 pA resolution in real HV + THGEM set-up Fulvio TESSAROTTO