-- MarkWard - 18 Jul 2017

13/07/2017 - Anode installed in the lab, in air test after first cleaning

Note - The electrical is set up to pass through the vacuum feedthroughs as though installed on the vessel.

CREMAT bias supplies - AC coupled amp box can be used without the chip, due to its being AC decoupled at the input. There is approximately 210MOhm resistance in the filter and bias chain. meausring the voltage drop necomes difficult unless a high impedance multi-meter. using a hand held device we appaear to have a large current draw. This behavour is due to roughly 10MOhm impedence being used to measurem the voltage. Note, 50V across the anode will be measured as 2.00V with a hand held. Used a bench multi-meter which has a high impedence >10GOhm at under 10 V. On this setting we measure the same voltage all the way through the circuit to the anode.

Temp = 24.9C Humidity = 37.7%

TR - 2.5kV @19:37

TL - 2.3kV @19:50

BR - 2.54kV @19:24 - started to see leakage current from approx 2.2kV

BL - 2.5kV @


Installed Anode onto the rails within DMTPC, performed two more cleaning passes

TR - 2.55kV leakage present from 2.4kV Humidity = 37.3, 3muA

TL - 2.6kV leakage present from 2.25kV Humidity = 37.7

BR - 2.55kV Humidity = 37.2 - 6muA

BL - 2.6kV Humidity = 37.1 - 4.53muA

Summary in terms of changes in stable voltage -

TR +50V

TL +300V

BR +10V

BL +100V

Note that one of the ground pre-amps appears to be not operating as expected, this channel has been grounded to the common grounding box directly (bottom left channel)

Source - Alpha - Middle of left half, pointing down

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Topic revision: r1 - 18 Jul 2017 - MarkWard

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