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AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40

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Wed Nov 18 18:18:26 2015

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Note: kapton #7 may have broken pins next to (deliberately) broken ground pin. Unclear, but should not be used for bias until certain.
Detector BB18 2998-22 connected via 4 45cm kaptons and biased to +200V via nnaida12+14, with leakage current 4.310uA @ room temp 25.4oC.
Turned off FADCs as per PCS instructions in previous entry - no change. Turned back on.
Braid grounding HV to pulser and all jumpers removed - makes performance much worse.
Connecting only jumper to ground detector brings performance back to moderate, but not good. Re-adding braid bring further improvement.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; - other jumpers don't seem to have a considerable affect on performance.
Added short (~few cm) drain wire to outside of Cu tape covering kaptons and attached to nearest allen bolt in adapter PCB, i.e. at the top of each connector, plus the jumper for the detector ground. Looked at variation with shaping time:
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; t_shape (us) &nbsp;&nbsp;&nbsp; ||&nbsp;&nbsp;&nbsp; 0.5&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 1.0&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 2.0&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 4.0&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 8.0
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Pulser FWHM (ch)&nbsp;&nbsp;&nbsp;&nbsp; ||&nbsp;&nbsp;&nbsp; 715&nbsp; |&nbsp;&nbsp;&nbsp; 687&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 448&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp; 246&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 124&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (nnaida14)
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; - all peaks were non-Gaussian and double peaked apart from at 8us. @ 8us it was not quite Gaussian, but much closer than the rest.
Added ~20cm drain wires to each kapton and connected all at one point on mount screw above nnaida14 adapter PCB connector. Again looked at variation with shaping time.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; t_shape (us) &nbsp;&nbsp;&nbsp; ||&nbsp;&nbsp;&nbsp; 0.5&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 1.0&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 2.0&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 4.0&nbsp;&nbsp;&nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 8.0
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Pulser FWHM (ch)&nbsp;&nbsp;&nbsp;&nbsp; ||&nbsp;&nbsp;&nbsp; 363&nbsp; |&nbsp;&nbsp;&nbsp; 354 &nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 245 &nbsp;&nbsp; |&nbsp;&nbsp;&nbsp; 120 &nbsp;&nbsp; |&nbsp;&nbsp;&nbsp;&nbsp; 85 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (nnaida14)
&nbsp;&nbsp;&nbsp;&nbsp; - again, at low shaping times all peaks started out double peaked, but moved closer to Gaussian as t_shape was increased. At 8us, not quite Gaussian, but close.
P-side performance much better than n-side.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; - currently drain wires are connected to p-side adapter PCB. Will move these to n-side PCB tomorrow to see if this has any affect.

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