Logbooks Lab Maintenance Evaporator_1 Evaporator_2 Laser cutter Target Production Test-Stand RH-ISAC RH-Cyclotron RH-Meson Hall RH-Beamlines RH-ARIEL
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Message ID: 1017     Entry time: Tuesday, August 06, 2024, 15:50
Author: Aaron Schmidt 
Target/No.#:  
Source:  
Station:  
Module:  
Target Oven W.O#:  
Heat Shield W.O#:  
Status: Problems/Solutions 
Subject: TS Troubleshooting - Leak/HV spark issues 

Due to HV sparking & possible water leaks on the previous TiC & Ta targets, checks are to be performed.

Chamber is empty. U-Line installed. All waterlines purged. FS#2, 3, 4, & 5 are closed.

Vacuum Group LD #2 - Connected to TP1B backing line

Tuesday, August 06, 2024, 15:50: Vacuum @ 3.38e-06T.

Tuesday, August 06, 2024, 15:52: No He connected. 7.0 E-09 atm-cc. LD TP pressure 1.0e-03T.

Tuesday, August 06, 2024, 16:20: No He connected. 1.1 E-08 atm-cc. LD TP pressure 1.0e-03T.

Tuesday, August 06, 2024, 16:23: Open to chamber. 1.6 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.97e-06T.

Tuesday, August 06, 2024, 16:26: 20 PSI. 1.6 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.97e-06T.

Tuesday, August 06, 2024, 16:32: FS#5 Charged with 20 PSI He. 1.6 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.75e-06T.

Tuesday, August 06, 2024, 16:34: Close FS#5

Tuesday, August 06, 2024, 16:35: FS#4 Charged with 20 PSI He. Increase to 2.5 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.75e-06T.

Tuesday, August 06, 2024, 16:42: While purging FS#4 with HPA, an increase of 8.3 E-08 atm-cc was observed. Vacuum @ 2.75e-06T.

Tuesday, August 06, 2024, 16:50: Re-connected He. FS#3 Charged with 20 PSI He. Increase to from 3.6 to 9.0 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.59e-06T.

Tuesday, August 06, 2024, 16:52: 5.1 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.57e-06T. Line still @ 20 PSI.

Tuesday, August 06, 2024, 16:53: Release pressure on FS#3. 5.1 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.57e-06T. Line still @ 20 PSI.

Tuesday, August 06, 2024, 16:55: FS#2 Charged with 20 PSI He. Steady @ 5.1 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.59e-06T.

Observed increases on FS#3 & FS4.

Tuesday, August 06, 2024, 17:02: All lines purged with HPA. Allow vacuum to continue down.

Tuesday, August 06, 2024, 17:03: Close off LD to TP1B valve. Dropped to 1.7 E-08 atm-cc. LD TP pressure 1.0e-03T. Vacuum @ 2.48e-06T. Safe to vent LD.

Tuesday, August 06, 2024, 17:06: LD vented & disconnected.


Wednesday, August 07, 2024, 09:15: Vacuum @ 6.43e-07T. Gradually refill the waterlines. 

Wednesday, August 07, 2024, 09:20: FS#5 open. Vacuum remains steady.

Wednesday, August 07, 2024, 09:28: FS#2 open. Vacuum @ 6.38e-07T.

Wednesday, August 07, 2024, 09:30: FS#4 open. Vacuum @ 6.38e-07T. Wait 5 min.

Wednesday, August 07, 2024, 09:35: Vacuum steady @ 6.36e-07T. Occasional dip to 6.27e-07T.

Wednesday, August 07, 2024, 09:36: FS#3 open. Vacuum steady. Wait 5 min.

Wednesday, August 07, 2024, 09:41: No change to vacuum.

While the helium did get through on yesterdays tests as a minor molecular leak, the water does not appear to have an affect. Moving to an empty HV test.

Wednesday, August 07, 2024, 09:53: Vacuum 6.20e-07T.

Wednesday, August 07, 2024, 10:43: Vacuum 6.20e-07T. IG1 & TP off.   -   venting test stand for target installation

 

Wednesday, August 07, 2024, end of day.  mass marker target installed in test stand with side foil removed so the target is visible through the view port. vacuum roughed, then turbo pumps turned on at end of day for overnight pumping

Thursday, August 08, 2024, 09:19 - vacuum at 6.27e-7T. water cooling was switched on. no effect on vacuum. TGHT and TBHT began ramping at 1A/30s. will test high voltage at low heat and at high heat.

 Thursday, August 08, 2024, 10:04   HV at 35kV. No sparks.  TGHT TBHT at <80A throughout HV ramp and plateau

Thursday, August 08, 2024, 10:14    BIAS down.  TGHT TBHT at 100A. increasing ramp rate to 1.7A/10s. heating up to 480/230

 Thursday, August 08, 2024, 13:59  BIAS has slowly been brought to 28kV . no sparks at all, despite being over 24kV for ~50min. 

Thursday, August 08, 2024, 14:00 increasing TGHT to 580A to attempt to induce sparks. 

Thursday, August 08, 2024, 14:42   at TGHT TBHT 580 230, HV bias at 28kV (with EZL and EE at 0 and 0), no sparks at all over the ramp and over 10 minutes at this condition. 

Thursday, August 08, 2024, 14:43 ramping HV to 30kV

Thursday, August 08, 2024, 15:01  - -  no sparks at 30kV.   bringing up EZL to 13kV  (EE=0)

Thursday, August 08, 2024, 15:11   -  no sparks with EZL at 13kV.  bringing up EE to -2500V

Thursday, August 08, 2024, 15:13  - no sparks with EE at -2500kV

 Thursday, August 08, 2024, 15:22   turned on beam optics to observe beam out, but no beam currently detected on FC0, nor on the wire scanners, nor on FC6. This target commonly has a normal beam output of primarily Na and K

Thursday, August 08, 2024, 15:50  have not been able to deduce reason for lack of beam. increasing BIAS to 50kV.

Thursday, August 08, 2024, 15:51  during ramp up, at 38kV, many optics elements tripped and switched off. however, no spark was registered at the strip tool. not sure of the cause for this.

Thursday, August 08, 2024, 15:54  at 38.8kV, a small spark, only registered on BIAS:RDCUR  (no voltage drop), tripped off beam elements prior to FC0 again.

Thursday, August 08, 2024, 16:00 BIAS at 40kV. no sparks apart from those mentioned immediately above. still have not registered any beam on FC0.

 Thursday, August 08, 2024, 16:02 Vacuum pressure has raised from 6.5e-7 to 1.3e-6 T.

Thursday, August 08, 2024, 16:03  just now, there was a spike drop in pressure and optics elements have shut down again. nothing registered on BIAS, EZL, or EE.

 

 

Thursday, August 08, 2024, 16:11   a spark occurred at 43.3 kV

 

 Thursday, August 08, 2024, 16:23  this spark was audible at the test stand --- ie, not inside

 

 

 Thursday, August 08, 2024, 16:51  Saw no indication overall of the same HV sparking issues that we saw with the previous two targets. However, we were unable to generate beam  register any beam output on FC0, FC6, or wire scanners.  And we don't mean 'low signal'. Actually nothing at all.

 

Thursday, August 08, 2024, 16:54   Ramping down TGHT TBHT now

Friday, August 09, 2024, 08:05   turbo pumps off and spinning down in preparation to vent. will remove the inner foil from the target to observe if a change in shine from the target induces sparking as before. 

Friday, August 09, 2024, 08:58   turbo pumps no longer spinning. venting now.

Friday, August 09, 2024, 10:26    foil stripped off the target. there was a hole in the source for gas (febiad/mass marker). This hole is now plugged. reinstalled, roughing.

Friday, August 09, 2024, 11:59   vacuum at 1.2e-5T.  turning on water cooling lines.  no effect on vacuum.

Friday, August 09, 2024, 12:50 heating TGHT TBHT at 1A/30s

Friday, August 09, 2024, 13:47 increasing heating rate to 1.7A/10s, up to 580/230A

Friday, August 09, 2024, 14:42  TGHT TBHT at 550 230,  increasing BIAS to 30kV 

Friday, August 09, 2024, 15:03   BIAS at 30kV.  no sparks other than a single small one at 25kV. No beam detected at FC0, FC6, or wire scanners.

 Friday, August 09, 2024, 15:18 increased BIAS again. there was one spark at 35kV, then it was stable for 8 minutes with no sparks. still no signal on FC0.  This lack of signal is highly irregular, and should not be the case despite being an empty target. Will have to compare to the next target in the test stand. To attempt to correct, we have:

- manually adjusted gain

- reset bias

- flipped polarity back and forth

- confirmed FC in position

- confirmed no flagged power supply issue

- confirmed clear beam line to FC0

- confirmed upsteam optics are tuned appropriately

 

Friday, August 09, 2024, 15:23  cooling target and ramping down HV

 Friday, August 09, 2024, 16:06 TGHT TBHT at 0. turbo pumps off and spinning down.

 

 

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