1. SuperKEKb X-Ray Monitor
new detector breakout board revB
reduces leakage paths (confirmed)
access to measure more nodes with hp4156b semiconductor parameter analyzer
using hp4156b to drive laser diode (thorlabs L980P010) and measure built-in photodiode
photodiode appears to have linear relationship to optical power, as measured by thorlabs S121B+PM100+hp4156b
plan to run at 24.5 mA
XRM 2018 progress

2. SuperKEKb X-Ray Monitor
first light! (on bench)
new laser driver board (revD)
drives cathode of laser directly from output of LVPECL comparator
drives anode from low output impedance buffer
better optical coupling into fiber and onto detector
partly from 3d printed 30mm cage mounts
partly from using 400um core fiber cable assemblies
partly from 3d printed fiber ferrule mounted in micro-translation stage
faraday cage for slac detector assembly
signal goes through 40dB mini-circuits amplifiers, then into scope in averaging mode
works down to 10 V bias (signal level is lower)
first light!
3 adjacent channels
laser driver revD
fiber coupling to translation stage
XRM 2018 progress

3. SuperKEKb X-Ray Monitor
amplifier selection:
carefully planning preamplifier+gain stages
calculation/simulation (noise/gain/recovery time)
prototyping/measurement (network analyzer)
firmware/readout:
modified BelleII/TOP firmware (common ancestor to previous XRM firmware) to (re)support gigabit ethernet
register read/write interface - working
streaming data out - working
trigger input (selectable prescaling) - in progress
retains compatibility with BelleII/TOP firmware and readout software (as much as possible)
upcoming:
next test is with SLAC strip detector and boardstack mated
XRM 2018 progress