NPS/CPS/COMCAL - Readout Hall C Collaboration FJ Barbosa Electronics NPS/CPS/COMCAL - Readout F.J. Barbosa, JLab Chief Electrical Engineer – Hall D J. Crafts, H. Mkrtchyan, J. Roche, A.Somov, C. Stanislav PMT & HV Divider Tests Readout Infrastructure Production Production Tests Summary 23 January 2018

1. PMT & HV Divider Each Crystal readout area is 20.5 mm square PbWO4 Hall C Collaboration FJ Barbosa Electronics 1. PMT & HV Divider Crystal PMT Each Crystal readout area is 20.5 mm square PbWO4 # Channels: NPS/CPS = 1156 COMCAL = 96 Uses Hamamatsu R4125 PMT. HV Divider Active Based on an earlier design by V. Popov Updated design for reliability, component and production optimization. New HV Divider (Active) 23 January 2018

Typical R4125 PMT Characteristics Hall C Collaboration FJ Barbosa Electronics Typical R4125 PMT Characteristics Diameter 19 mm Spectral Sensitivity 300 nm – 650 nm (Borosilicate, Bialkali) Stages 10 stage Cathode Luminous Sensitivity 115 uA/lm Anode Luminous Sensitivity 100 A/lm Dark Current 10 nA QE 27 % Rise Time 2.5 ns Transit Time 16 ns T.T.S. (Jitter) FWHM 0.85 ns Pulse Height Resolution 7.8 % Long Term Stability 1 % Pulse Linearity +/- 2 % @ 100 mA Gain 105 @ 1.1 kV --- 106 @ 1.5 kV 23 January 2018

Why an Active HV Divider? Hall C Collaboration FJ Barbosa Electronics Why an Active HV Divider? Regulation on the last two dynodes provides for excellent stability and linearity at high rates, large dynamic range. Operating the PMT at lower gain leads to longer PMT life. Dynode Regulation - Last item in the HV divider chain - Zener Regulated - CB Input PNP-NPN Driver Shaper - ~X10 Gain 2012 IEEE NSS/MIC – V.Popov, H. Mkrtchyan Preamp is powered from HV supply, eliminating LV supply, connectors, controls, etc. Higher current from HV supply: 430 uA vs. 170 uA (passive). HV = -1.1 kV. PMT Gain = 105 --- Total Gain = 106 23 January 2018

2. Tests Laser Tests Wavelength 405 nm Pulse Width 70 ps Hall C Collaboration FJ Barbosa Electronics 2. Tests Laser Tests Neutral Density Filter HV Divider Wavelength 405 nm Pulse Width 70 ps Rate Adjustable Up to 100 MHz Intensity Adjustable Class 3B PMT R4125 HV Divider Active HV -1.1 kV Cable Length Short 10 ft Long 55 ft Readout Scope (1 GHz, 5MSPS) fADC250 Laser Diffuser PMT LED Neutral density filter allows for amplitude adjustments within the fADC250 range of 500 mV. Test Variables: Intensity, rate, output drive capability 23 January 2018

Readout Pulse Characteristics – Impulse response Hall C Collaboration FJ Barbosa Electronics Readout Pulse Characteristics – Impulse response Amplitude 427 mV Tr 2.1 ns Twidth (FWHM) 6.2 ns Rate 1 kHz Cable length 10 ft 4 ns 100 mV Results agree with PMT stated characteristics: Tr is slightly better due to shaping at the output driver. Similar performance with long cables (plus dispersion, attenuation, etc.) 23 January 2018

Pulse amplitudes = 100 mV to 400 mV Rates = 1 kHz to 5 MHz Hall C Collaboration FJ Barbosa Electronics Pulse amplitudes = 100 mV to 400 mV Rates = 1 kHz to 5 MHz Linearity is better than 2% up to 2 MHz A 500 mV pulse corresponds to 1 mA peak anode current --- 1% of PMT spec Improved linearity, stability, lifetime 23 January 2018

Pulse shape behavior with fADC250 was as expected. Hall C Collaboration FJ Barbosa Electronics Tests with LED and fADC250 Tests were performed in Hall D with an LED to verify operation with full DAQ. Pulse shape behavior with fADC250 was as expected. Linearity was worse: 4% and 1 MHz … at lower amplitudes, likely due to LED near breakdown and slower edges from pulser. 23 January 2018

3. Readout Infrastructure Hall C Collaboration FJ Barbosa Electronics 3. Readout Infrastructure Hall C installation details not yet finalized – Patch Panels, Connectors, Cabling 23 January 2018

Hall D installation details have been finalized: Hall C Collaboration FJ Barbosa Electronics Hall D installation details have been finalized: COMCAL only has 96 channels, Patch panel with Lemo (signal) and SHV (HV) 23 January 2018

4. Production HV Divider assembly consists of various parts: RG174 Hall C Collaboration FJ Barbosa Electronics 4. Production HV Divider assembly consists of various parts: Cable Assemblies PMT Socket RG174 Rated for 1.1 kV RMS operation. Used inside detector chassis, not CL2 rated. Wire Connections Connectors NPS/CPS - TBD COMCAL - LEMO,SHV Prototype version shown PCB Assembly 23 January 2018

Hamamatsu socket needs to be machined: Hall C Collaboration FJ Barbosa Electronics PMT Socket Hamamatsu socket needs to be machined: Metal ring is removed with hand tools a bit of an effort needed. The plastic piece has a lip Removed by machining Easy after setup Required to fit detector PMT assembly housing. COMCAL - 100 have been modified. NPS/CPS recommend getting socket without metal ring from Hamamatsu Removal of lip still required. PMT Socket (original) PMT Socket (modified) 23 January 2018

PMT Socket attachment to PCB Assembly Hall C Collaboration FJ Barbosa Electronics PMT Socket attachment to PCB Assembly PCB assemblies were procured via contract ( PCBs + component assembly) PMT Socket (modified) Wire connections PCB Assembly Wiring socket to PCB assembly is labor intensive Cut wires to length, strip ends, heat shrink insulation, solder Radially compact assembly, as required by detector PMT housing. 23 January 2018

Cable assemblies attachment to PCB Assembly Hall C Collaboration FJ Barbosa Electronics Cable assemblies attachment to PCB Assembly Cable assemblies were procured via contract (cable + connectors, ½ each the # of PMTs) Bulkhead connectors PCB and Socket Assembly Bulkhead connectors secured to detector chassis, patch panel. Cables attached to PCB Assembly Two cable assemblies: LEMO-cable-LEMO and SHV-cable-SHV (COMCAL) Cables are twice as long as needed Assembly: Cut cable assemblies in half, strip ends and solder to PCB Consider labor needs. Production version shown 23 January 2018

Hall C NPS/CPS – OU, Julie Roche Hall D COMCAL – Jlab, FJ Barbosa Hall C Collaboration FJ Barbosa Electronics Production Status Two initiatives: Hall C NPS/CPS – OU, Julie Roche Hall D COMCAL – Jlab, FJ Barbosa NPS/CPS HV divider PCBs are in production Delivery to OU this week First article tests to follow (Jlab will help) Remaining steps TBD by Julie (OU) (Jlab will help as needed) COMCAL HV divider PCBs have been received (100) PMT sockets modified (100) Cable assemblies have been received (100) Assembly of completed units under way PMTs received (100) PMT tests have started Remaining hardware (fADC250s, crates, HV modules and chassis, cables) has been procured in preparation for installation in Hall D in the Fall of 2018. 23 January 2018

Hall C Collaboration FJ Barbosa Electronics 5. Production Tests Testing plan is still evolving as to which parameters should be measured for: all PMTs a few PMTs (From batches? How many?) HiPot test all HV dividers at -1.1 kV: no arcs, no trips, supply current < 430 uA Characterization tests of all PMTs on a single HV divider against a reference known good PMT or comprehensibly : Gain Rise time Linearity QE Pulse height resolution Stability Test all HV dividers with a reference PMT (HV required to test preamp) Or pair PMTs with HV dividers to form identified units ready for installation: Tests performance of PMT and HV divider HV and signal 23 January 2018

We developed a portable optical dark box Hall C Collaboration FJ Barbosa Electronics Test Setup We developed a portable optical dark box 12 x 36 x 16 inches Lid Latch (2) Added connectors, both ends (HV, Signal, LED Pulser) 23 January 2018

LED Pulser:Tr, Tf < 2ns,Tw = 5 ns, Fr =1 kHz. Hall C Collaboration FJ Barbosa Electronics Inside the box: Setup: HV In Make connections to box: HV, Signal Out to scope or DAQ, LED Pulser In to signal generator. Settings: HV = -1.1 kV LED Pulser:Tr, Tf < 2ns,Tw = 5 ns, Fr =1 kHz. Signal Out HV divider PMT Holder Test Procedure: Bracket w/stop (3D printed) Attach PMT to HV divider Insert PMT into PMT holder until PMT contacts stop [for repeatability]. Close lid. Turn on HV. Reverse procedure after tests and repeat for next PMTs and/or HV dividers. Diffuser Blue LED Pulser In Optical Plate (Al, 1/2”) 23 January 2018

Hall C Collaboration FJ Barbosa Electronics 6. Summary Active HV dividers for the Hamamatsu R4125 PMT have been developed, assembled and tested: Good performance characteristics: linearity, rate, stability, drive Allows operation of the PMT at lower gain, extending its useful life. The NPS/CPS detector infrastructure is under development Choice of connectors, patch panels, etc to be finalized. HV dividers in production after 1st article acceptance next week. The COMCAL is scheduled for installation during the Fall of 2018, depending on the availability of Crystals. HV dividers produced and undergoing final assembly PMT tests (preliminary): 70 of 70 PMTs passed tests but 2 are marginal. Final assembly (PMT socket, cables) of the HV dividers is labor intensive. An assembly manual is being prepared. Production test procedures are being finalized and with consideration to available resources. Developed a portable optical dark box to ease production testing of PMTs and HV dividers. We can help the NPS/CPS Jlab/OU effort. 23 January 2018