Module Failures on Rods

Current Failures of Modules on Rods UCSB 1 module (6662) had a saturated channel on rod during production exercise 1 rod had three modules (6046, 6264,5850) with saturated channels and one module (6503) with high current during production FNAL 1 module (4047) had saturated channels on a non-production DS rod 1 rod had three modules (8241, 8242, 8244) with saturated channels on a non-production rod

UCSB Rod #1 Channel 67 saturated on rod, confirmed on ARCS stand After plucking PA-Sensor wire bond, APV acts like open Channel a regular pinhole Visual inspection shows damage to channel on both sensors Defect in manufacturing, same sensor batch Pinhole is type of failure we are expecting during burn-in

UCSB Production Rod 3 edge channels failed on 3 modules (Positions 1, 2, 4) on one production rod Modules failed on SRT, with old DAQ/CAEN controller software and new interconnect cards All three saturated channels confirmed during ARCS tests 1 of 3 channels show visible damage to saturated channel on APV One additional module has increased bias current but no new bad channels Input to APV Beginning of PA

UCSB Production Rod All 3 channels stay saturated when PA-sensor bond pulled For 2 modules without visible damage to APV, noise on neighboring channels disappeared with wire bond pull Appears blown APVs driving noise into sensor No extra current in LV or HV Bonded functioning APV channel to sensor channel that was connected to blown APV channel All 3 sensor channels ok, no pinholes or noisy channels On module with visible APV damage, bias current increased to 12 mA Now module fails bias current requirements

UCSB production rod On module with high current but with no new bad channels, a burn mark was found on the corner of the second sensor on the metal where the numbering is It is not clear to me how this could happen Leads me to believe failures are due to something on the high voltage Guard Ring Outside Edge Metal

FNAL DS Rod 1 module had multiple saturated channels on a DS rod Module failed on MRT with old DAQ/CAEN controller software and old interconnect cards Extremely high current-10 mA at 40 V Initially, channels 37-39 have blown APV channels in first ARCS test During subsequent ARCS tests, more blown APV channels develop

FNAL SS6 Rod Multiple channels fail on 3 modules (Positions 1, 2, 4) on non-production rod Modules failed on MRT with updated DAQ/CAEN software and old interconnect cards Rod tested multiple times previously with no problems All three modules’ faults confirmed on ARCS stand Visible damage seen on APV for one of the modules

FNAL SS6 Rod Module 8241- APV channels 283-285 dead Module draws up to 10 mA

FNAL SS6 Rod Module 8242- APV channels 451-452, 724-725 dead + noisy channels Module draws up to 4 mA

FNAL SS6 Rod Module 8244- APV channels 62-64 Module draws up to 8 mA

Summary/Conclusions Modules are recently developing dead APV channels on rods but no commonality Both DS and SS rods effected Two rods have positions 1, 2, 4 effected At UCSB always single edge channels; at FNAL groups of channels in middle of modules On some module increased current seen, others no increase seen 1 tested on SRT, 2 tested on MRT 2 tested with old software/1 tested with updated software 2 rods had old interconnect cards, 1 rod has new ones 1 rod had retrofitted modules, 2 rods had non-retrofitted modules Failures occurs at approximately the same time after large number of rods tested at both sites