New Discriminator Board Test 1. Leading Edge Timing 2. Width of Pulse Eric Oberla & Heejong Kim

New & Slow vs. Old & Fast outputs outputs Input Input Input New board with slow comparator Old board with fast comparator

New disc. board Features Test Method Equipped with cheaper comparators. Physically 1 card contains 2 separate units of disc. board. Test Method Use a pulse generator square pulse: 600 mV height. ~10 ns width. ~2 ns rise time. 2. Split into two and fed to each input of 2 boards. 3. Read-out 8 outputs using HPTDC. 3. Time offset : ch1-ch2, ch1-ch3, ….., ch1-ch8. Expect small spread. 4. Width of leading and trailing edge. Expect ~ 10ns width for all 8 channels.

Time offset between channels From New board RMS : ~300ps From Old board RMS : ~25ps Cf. Distribution for other channels can be found in separate pdf files.

Width of output Input pulse width : ~10ns. From New board RMS : 2.44ns From old board RMS: ~107ps Input pulse width : ~10ns. Unstable output width can be seen easily using a oscilloscope. Need to investigate possible reason.