Active Dividers Tilecal upgrade meeting at Valencia (19-21 November 2014) François Vazeille on behalf of Roméo Bonnefoy, Michel Crouau (Now retired), Dominique Pallin, Christian Fayard, Marie-Lise Mercier, Eric Sahuc, Timothée Theveneaux-Pelzer PMT issues Concept of active Dividers Systematic tests of passive/active dividers Radiation tests Conclusion 1
● PMT issues D1 … D8 *2 PMTs back to LPC: PMT signal PMT Test Bench could provide useful information. PH A Effect on PMT entrance: Gain ↓ instantaneous L , ↑ integrated L, already seen from Tiles close to the Beams*. High Lumi. Effects on the last Dynodes: Gain ↑ at HL-LHC. Minimum Bias Events at HL-LHC High DC current on the last dynodes ( Amplification at each stage) Decrease of the interdynode voltages Increase of voltages on the first dynodes because HV kept constant Increase of PMT: non-linearity of AC pulses for high DC currents. 2
● Concept of active Dividers Passive Dividers Active Dividers ▪ Transistors on the last 3 stages ▪ High sensitivity to high DC current Constant voltages. Non linearity to AC PMT pulses ▪ Diodes on the 3 last stages Protect transistors/Off-On switching. 3
● Systematic tests of passive/active Dividers Active Passive ▪ Without PMTs: on the Divider Test Bench Comparisons of sets of 10 passive/active Dividers. ▪ With PMTs: on a dedicated set-up Comparisons for a given AC pulse (~ 100 GeV) of 20 sets ″PMT -passive- active Dividers″ as a function of DC (Minimum Bias). No other electronics than a scope (No bias) 4
Full concept validation with the goal of NL < 1% Atlas Note Active Dividers for the Tile Calorimeter for the ATLAS Detector ATL-TILECAL-INT-2014-005 (02 July 2014) [Clermont-Ferrand authors] 27 pages Tiles 10 µA DC max at HL-LHC Cracks 40 µA Passive Active 10 µA 3.4 ± 0.6 50 µA < 0.5 40 µA 13.5 ± 2.4 120 µA < 1 Non-linearity in % versus DC (Averages over 20 bases) - Passive Dividers are no longer fitting the specifications. - Active Dividers fit perfectly with a large safety margin. - Not shown today: good agreement with simulations. 5
● Radiation tests Irradiated PCB 20 Dividers (Atlas rules) and also 8 Diodes and 16 Transistors ▪ ATLAS rules on location, simulations, new Safety factors NIEL: 0.6 10 13 eq-1 MeV n/cm 2 (pushed up to 1.5 10 13 old Safety factors) TID : 225 Gy (pushed up to 525 with old Safety factors) ▪ Test Bench + PCB + Analysis: Clermont-Ferrand with a current injection of 40 µA on dynode 8 (to push the NL). ▪ Irradiations Neutrons: Valduc (CEA France) by Clermont-Fd team. Gammas: Brookhaven (USA) by Argonne team. 6
Full certification at the official doses and also at the upper doses. 5 criteria on Dividers and also Diodes and Transistors Atlas Note " NIEL and TID certifications of the active Dividers of the Tile Calorimeter of the ATLAS detector for the Phase II upgrade ATL-COM-TILECAL-2014-074 (Submitted) [Argonne + Clermont-Ferrand authors] 44 pages - R&D completed with success. - Production/Certification of 350 active Dividers for ATLAS 2015 (Cracks et MBTS). - Test Bench refurbished for both passive/active Dividers ready for future productions. - ATLAS decision to come about a partial/total replacement for the upgrade. 7
Full certification at the official doses and also at the upper doses. 5 criteria on Dividers and also Diodes and Transistors Atlas Note " NIEL and TID certifications of the active Dividers of the Tile Calorimeter of the ATLAS detector for the Phase II upgrade ATL-COM-TILECAL-2014-074 (Submitted) [Argonne + Clermont-Ferrand authors] 44 pages 8
● Conclusion - R&D completed with success. - Production/Certification of 350 active Dividers for ATLAS 2015 (Cracks et MBTS). - Test Bench refurbished for both passive/active Dividers ready for future productions. - ATLAS decision to come about a partial/total replacement for the upgrade. - Clermont-Fd will provide all information and software drawing plus the Test Bench, to the Institute ready to make the production. 9
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