UoM activitiesThe Usual (and More) Suspects

New Arrival Time Fit FunctionAAT0002 gas performance

Initial tests with Br doped gases

New Arrival Time Fit Function

6/24/14 UoM activities 2

AAT0001HV=1150V

AAT0002 Voltage Scan (Zoe)

6/24/14 UoM activities 3

Arrival Time AAT0002 at 1000V

6/24/14 UoM activities 4

6/24/14 UoM activities 5

Arrival Time AAT0002 at 1020V

UoM activities 6

Future Microcavity Experiments

• Repeat voltage scan for the same pixel (for reproducibility) while extending the HV range

• Arrival time at higher HV• Try as AAT0003 Ne + 0.4% Ar + 1% SF6 :

replacing CF4 with SF6 in AAT0002 to see if it works at higher HV and so shrinking the arrival time distribution.

6/24/14

UoM activities 7

New Gas Mixing Station

6/24/14

MixingVolumeValve

Panel Valve Shutoff

Gauge

Bypass

Vacuum

Gas AGas B

Needle

UoM activities 8

Initial Tests with Br-gases on VPIAr + 0.5% Br (bottle) at 747 Torr1. No pulses observed up to HV=1000V (mV threshold)2. At around 500 V, not null current:

a) onset of current is sharp and repeatable at 495-500 V.b) The current is at the level of a microamps, but increasing

nonlinearly with increasing voltage. At 600 V a ~15% increase in HV leads to about 1.7-1.8 increase in current.

3. HV polarity reversal attempt: briefly bipolar pulses, unrelated to source.

Pure Argon at 741 Torr4. Large amplitude pulses (>30V) at ~740 V and above.

Some lines are much more active than others, but not visible response to the source. Easily in regeneration.

6/24/14

UoM activities 9

Initial Tests with Br-gases on VPI (2)Ar + 0.05% Br at 734 Torr• Seen a few pulses (~6V amplitude) for a minute or so

around -460V, then nothing.• After polarity reversal again a few pulses and then

nothing.• Interestingly with HV=+1kV bipolar signal visible.• Also a unipolar signal 5-8 ns wide is observable, although

unclear if it was in response to the source.Ar + 0.01% Br at 730 Torr• Still to be tested (filled yesterday)If it does not work, we will move to 3 components gas starting with Ar + 0.5% Br + 0.5% Xe.6/24/14