22/09/20044 Hamamatsu and FEU 187 gain 19 dynodes 16 dynodes 15 dynodes Hamamatsu FEU 187
22/09/20045 Hamamatsu / FEU MIP measurement at equal gain 17 p.e. for the most probable charge 12 pC / 60 mV charge = MIP / 4 for Hamamatsu PMT charge = MIP / 2 for Russian PMT time (Ham.) = 1.5 time (FEU 187) a threshold at 2 charge (98%) - MIP / 2 mV for Hamamatsu (30 mV) - 0 for FEU 187 Hamamatsu will be selected for V0
22/09/20046 time versus discriminator threshold 17 p.e. 2 > 0 mV 2 > 30 mV dynamics: 3 mV-3 V MIP amplitude > 60 mV Ham. FEU 187
22/09/20047 MIP versus discriminator threshold 17 p.e. Maximum efficiency 2 MIP efficiency
22/09/20048 H = R HV divider (+) PMT and divider in in a common cylinder makes the mounting easy simplifies the mechanics
22/09/20049 Electronics for tests with the schoebox A10/A25 V0 counter optical fibers TDC1 PM HT 30 ns gate QDC THR1 5 m anode FI/FO THR2 THR3 THR4 TDC2 TDC3 TDC4 start 25 m 17 p.e./MIP thr4 thr3 thr2 thr1 ped qdc ped disc shoebox A1 CFD TDC4 thr
22/09/ Measurement with the shoebox 16 dynodes Hamamatsu tube Charge distributions as a function of - high voltage: 1400, 1600, 1750, 1800, 2000, amplification factor: 1, 10, 25 Time resolution with amplification 10 and threshold / constant fraction discriminators as a function of - high voltage: 1400, 1600, 1800, 2000, 2200 Extraction of the time resolution values still to be carried out
22/09/ Charge distributions at 1400 V from 16 dynodes Hamamatsu PMT Without shoebox HT= 1400 V, A=1 HT= 1400 V, A=25 HT= 1400 V, A=10 HT= 1400 V, A=1
22/09/ T0 schoebox as described in TDR
22/09/ V0 pulse treatment
22/09/ /10/2004 CIU PCB prototype
22/09/ /11/2004 Tests in progress
22/09/ Conclusion Choice of the Hamamatsu PMT 16 dynodes gain = at 2000 V (FEU = ) charge resolution = MIP/4 (FEU = MIP/2) time resolution (MIP = 17 p.e.) < 1 ns at 1750 V (FEU # 1.4 ns) Choice of the T0 shoebox with an amplification of 10 direct signal to QDC amplified (clamped) signal to discriminator
22/09/ Quotation from Hamamatsu France
22/09/ V0 cost for 64 channels (R ) labelunitspareunit pricetotal price H (R ) HV SY2527/A1733P1/6-8812/ VME Electronics Mechanics PM + boxes Scint. V0A/V0C (m 2 )2 x WLS F. V0A/V0C (m)2 x Clear F. V0A/V0C (m)2 x Total in € Total in SF HV cab. V0A/V0C (m) HV con. V0A/V0C(448)-4756 Sig. cab. V0A/V0C (m)2 x Sig. con. V0A/V0C(2 x 576) Total in SF353981
22/09/ Present programme Order of: VME crate: 15/12/ systems H (PM HT divider): 15/12/ delivery: 10 (06/2005), 20 (07/2005), 20 (08/2005), 20 (09/2005) scintillator BC404: 15/12/2004 shifting fibers: 15/12/2004 optical fibers: 15/12/2004 Sector ’’0’’: available: 03/2005 tested: 04/2005 design review: 04/2005 Sectors ’’1’’ - ’’7’’ + V0C box + V0C fiber cables available: 11/2005 tested: 12/2005 PM characterisation: gain curves: 12/2005 V0C ready end of 2005 V0A ready in June 2006 Electronics R&D: follows the time-table (TDR) CIU prototype tested: end 2004
22/09/ Recommendation for the HV sign 1) The R and the R are for +HV operation. > > We usually recommend +HV operation for all of the Fine Mesh PMTs. The > reason is as follows: > > Basically, there is no difference in PMT itself between -HV model and > +HV model. When a fine mesh PMT is operated at -HV, it sometimes > generates large noises. This is due to discharge between electrodes > (former stages of dynodes), the bulb and supporting materials outside. > Fine mesh PMT has proximity configuration, the electrodes are set > close to the window and the bulb. When -HV is used, potential of these > electrodes become -HV. There could be large potential difference > somewhere around window. In case of +HV operation, as cathode is > grounded, there is less potential difference between electrodes, the > bulb and supporting materials. Therefore noise becomes less. We would > like to recommend +HV operation for all customers.
22/09/ Here is the anode dark current stability data of the R5946 (1.5« Fine Mesh PMT). The horizontal axis is operating time and the vertical axis is the anode dark current recorded by ampere meter and recorder (10 mV = 100 nA). The upper data was measured at -HV operation and the lower one was measured at +HV operation. The PMT was supported by its socket, and there was nothing around the PMT bulbs. Spike noises appeared at -HV operation. However, when it was used at +HV operation, the noise became less.
22/09/ Waveform of the pulse 2. We checked the waveform of the R5505(1 inch Fine Mesh PMT) and the following is its data. Blue curve is at -HV operation and pink one is at +HV operation. Although the overshoot was rather seen at +HV, it's not so much. Therefore, we would like to recommend +HV operation.