<p>New Kapton PCB design (2x 0.45m + inter-connecting PCB, no ground plane layers) under test with small system in T9.</p>
<p>3 cables modified to remove ground connection.</p>
<p> </p>
<p>When just connected to system and BB18 2998-20, with no additional grounding or shielding of the cables</p>
<p>and bias of +200V (leakage current +6.2uA, ambient temp +27 deg C) to nnaida14, we observed average pulser peak widths</p>
<p>of ~250ch FWHM</p>
<p>Waveforms were just noise.</p>
<p> </p>
<p>Added heavy duty copper braid between adapter PCBs, the small metal box for the detector and Cu tape and drain wire to the kapton connected to nnaida14.</p>
<p>This reduced the peak widths to ~160ch FWHM</p>
<p>Adding grounding between the adapter PCBs and the NIM bin chasis increased the peak widths.</p>
<p>Waveforms for nnaida11-13 remained unchanged, but expected (albeit noisy) traces could be seen for nnaida14).</p>
<p> ------> Patrick: with ASIC1 waveforms for all nnaida turned on, we found they would occasionally stall for some. e.g. of 4 being observed, upon update, only 1 or 2 actually would. Stop-Go did not resolve this. Load/check ASIC resolved issue.</p>
<p>nnaida14 developed double peaking of pulser peak.</p>
<p>Note waveforms exhibit significantly faster risetime than previous Kapton PCB variants => lower C, as expected</p> |