1. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A Electron detectors for HAPPEX2 and He Installation in HRS Linearity tests 4

2. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A Detectors

3. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A Installation Installation procedure to be tested next week in the Hall Coordinate with installation of scanners

4. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A Linearity and Asymmetry - Output signal of the PMT : - Asymmetry measured : The nonlinear term is proportional to the signal amplitude. - HAPPEX requirement :

5. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A Mode of operation of the tube 1.Integrating mode : -High beam intensity (80 – 100 mA) -Rate in HRS t = 50 MHz in the whole detector -Low gain region -Continuous signal less than 6 A to match ADC range 2.Pulse mode : - Background study and Q2 measurement -Low beam intensity (factor 200 less counting rate to fire VDCs) -Rate in HRS t = 10 KHz/cm2 -High gain region -pulse signal of a few mA need large dynamic range and good linearity capability 33 ms

6. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A PULSE mode linearity setup Method : -HV Blue LED (430 nm) Remote Filter wheels 8854 BURLE PMT Pulse generator Att dB -2 dB ADC Ped S(La)S(Lf) Deviation from linearity : Normalization (1 st order) : Light flux PMT response LaLf

7. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A PULSE mode linearity - Non linearity at high gain due to saturation in latter dynodes - operating range is in a good linearity region Resistive base Active base N e- 250 2% Operating range

8. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A Linearity in continuous mode setup Micro Amperemetre DC voltage Shutter 1 Shutter 2 -HV Plans to implement this method online for the HAPPEX-2 run Method : Use of additivity

9. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A Linearity in continuous mode Results for average continuous current Is the pulse structure still relevant ? Evaluation of the real output current is done with a duty factor of 2 or 3 Resistive baseActive base ADC range 2%

10. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A Gain drift Measurement of Drift in gain with a pulse signal and a load of continuous light background of 1, 5, 15 A Load ONLoad OFF Gain do depends on output current but timescale very long. no systematics from rate-gain correlation at 30 Hz

11. Antonin Vacheret DAPNIA/SPhN, CEA Saclay.HAPPEX II Jlab Hall A conclusion - Complete tests of linearity for the BURLE 8854 + base - Resistive base : H gain G = [1E6-3E6] output = [2-8] mA L gain G = [5E3-1E4] output = [10-20] A + filters (0.5,0.2,0.1) - Active base : H gain G = [1E6-1E7] output = [2-20] mA L gain G = [1E4-2E4] output = [20-40] A + filter (0.1)