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Message ID: 2668     Entry time: Tuesday, August 20, 2024, 11:53
Author: Carla Babcock 
Category: South Hot-Cell 
Type: Standard Operation 
Module:  
Target/Number: Nb#10 
Subject: Nb#10 PIE 

Nb#10 never worked online - repeller had no effect on the beam and one of the RF wires was touching HVC. Max 60pA was seen on the source cup. See notes here ITW-TM2-Nb#10/#11-LP-IGLIS  (Web view)

Target was handled roughly after use - kicked around in NHC for a long time, then loaded into a pail (multipin had to be dettached for this) then moved to SHC, unloaded from pail, then plates covering the RF electrodes had to be pried off. Lots of knocking and shaking.

Theory was that the repeller wire was disconnected. But found it not obviously broken, had good continuity from the ring tongue to the end of the wire pulled out of the multipin, even after all the abuse. Same for the RF (from the end of the electrode to the end of the wire pulled out of the multipin). Did find some of the multipin wires were flaky - if moved around they showed intermittent shorts to HVC. But not clear if this is from the rough handling afterwards or not. The problem was not in the module since NB#11 ran immediately afterwards with no issues. Most likely culprit seems to be the insulation beads on the wires. Should look for more robust insulation solutions. On the other hand, the connections of the wires to the electrodes seems very good.

Still not sure why no effect of the repeller was seen. Could be a intermittent break/short, though this seems unlikely. Maybe the connection in the multipin was not good? I did not get a chance to inspect that.

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