AIDA
GELINA
BRIKEN
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CRIB
ISOLDE
CIRCE
nTOFCapture
DESPEC
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CARME
StellarModelling
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K40
AIDA
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Entry time:
Sun Mar 30 09:19:16 2025
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<p> <table width="98%" align="center" cellspacing="1" style="border:1px solid #486090;"> <tbody> <tr> <td cellpadding="3px" style="background-color:#486090; font-weidht:bold; color:white;">Quote:</td></tr> <tr> <td cellpadding="10px" style="background-color:#FFFFB0;"><p> 25/01/16</p> <p>On start up, received error when trying to access spectrum browser (attachment 1) => required restart of 'Http for AIDA'</p> <p>At 2us shaping time, and all other setting as last week, the situation remains the same</p> <p> - nnaida11 has width ~50ch, nnaida12 has width ~300ch, nnaida13 is quad peaked and nnaida14 is not quite Gaussian but has width of ~80ch (possibly two peaks very close together)</p> <p>Change shaping time to 8us.</p> <p>Swap cables to see if the cable is the source. Currently have two LH coupler + shielded ribbon cables connected to nnaida11/13 (11 good performance, 13 quad peaked)</p> <p> - swapped the ribbon cables over but left the couplers where they were to see if the good performance is a consequence of something intrinsic to a particular ribbon or coupler.</p> <p> - nnaida11 now has width ~40ch (attachment 2)</p> <p> - nnaida13 now back to double peaked (attachment 3)</p> <p> - inconclusive.</p> <p>Could old style kapton laid next to nnaida11 be shielding it due to the built in screen? (the kapton is laid against the ribbon cable)</p> <p> - removing the kapton makes no difference to widths, other than nnaida12 which comes down to ~15ch (as expected)</p> <p>Clipping cable ends together makes no difference, and no combination of jumpers could improve the widths.</p> <p>Bending cables through 90 degrees makes no difference either (if they were acting as aerials).</p> <p>Swapped complete PCBs with cables still in place over. Test first thing tomorrow.</p> <p> </p> <p>26/01/16</p> <p>Swapping PCBs produced no difference</p> <p> - nnaida11 has widths of ~50-60ch, although some structure visible in some peaks</p> <p> - nnaida14 sees double peaks.</p> <p>Clipping ribbon ends together now makes things worse.</p> <p>Swapped PSU cables to nnaida11/14</p> <p> - nnaida11 now marginally worse @ ~70ch width</p> <p> - nnaida14 sees no obvious change</p> <p>Connected PSU chasis to NIM crate - no change.</p> <p>Added two more ribbon + HL/RH couplers to system. Now:</p> <p> - nnaida11 = LH + ribbon</p> <p> - nnaida12 = LH + ribbon + RH</p> <p> - nnaida13 = LH + ribbon + RH</p> <p> - nnaida14 = LH + ribon</p> <p>Clipped drain wire to LEMO connectors on PCB instead of pulser BNC cable.</p> <p>See marked improvement in performance. All nnaida now have single Gaussian peaks with widths now: (attachments 4-6)</p> <p> - nnaiada11 at ~35ch</p> <p> - nnaida12 at ~70ch</p> <p> - nnaida13 at ~80-120ch</p> <p> - nnaida14 at ~45-55ch (3 at ~80-150ch)</p> <p>Added RH coupler to nnaida11/14, with thin braid taped over joint in shielding to reduced resistance</p> <p> - nnaida11 widths increase slightly to ~40-60ch</p> <p> - nnaida14 widths increase slightly to ~60-80ch, few round ~100-120</p> <p>This is consistent with the RH coupler increasing widths by ~25ch, as seen in previous tests.</p> <p>See occasional ripple through waveforms in nnaida11/14 (attachments 7-11).</p> <p> - expanded view shows period of 34 samples ==> 680ns ==> frequency ~1.5MHz</p> <p>Variation with shaping time (avg peak width over a several channels):</p> <table width="200" border="1" cellpadding="1" cellspacing="1"> <tbody> <tr> <td>t_shaping (us)</td> <td>nnaida11</td> <td>nnaida12</td> <td>nnaida13</td> <td>nnaida14</td> </tr> <tr> <td>0.5</td> <td>35</td> <td>48</td> <td>60</td> <td>55</td> </tr> <tr> <td>1.0</td> <td>46</td> <td>60</td> <td>80</td> <td>65*</td> </tr> <tr> <td>2.0</td> <td>50</td> <td>70</td> <td>100</td> <td>70</td> </tr> <tr> <td>4.0</td> <td>60</td> <td>60</td> <td>85</td> <td>85</td> </tr> <tr> <td>8.0</td> <td>55</td> <td>54</td> <td>60</td> <td>65</td> </tr> </tbody> </table> <p>* = some non-Gaussian peaks</p> <p>Connected detector, biased to +200V (+ve core to nnaida12, -ve braid to nnaida14) with leakage current = 9uA.</p> <p>At 8us shaping time, and with Lk1 fitted on nnaida13/14 RevC adapter, peaks across all nnaida have widths ~70ch and are all single Gaussian peaks. (attachments 12-15)</p> <p> </p> <p> </p></td> </tr> </tbody> </table> </p><p> </p>
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