Flow rate
Fe55 with premixed 50/50 Ar/CO2, New preamp and new HVB, ADC half-range, for a range of HV and (later) gas flow rate
From New HVB:
Mixed 50/50 at 80 sccm total, less HV
Mixed 50/50 at 40 sccm total - note the change in x-axis scale. The 2050V run was wrong initially, corrected 1340 Oct 27.
Various gas flow rates at 1850V (left) and 2050V (right)
Events at 80 sccm total, 1850V (left) and 2050V (right)
Events at 40 sccm total, 1850V (left) and 2050V (right)
As above, zoomed in on pedestal... 80 sccm total, 1850V (left) and 2050V (right)
40 sccm total, 1850V (left) and 2050V (right) The little blip at ~ch 250 in the RH plot is an afterpulse, this is not noticeable at 2000V.
Premixed gas at different flow rates, cylinder -> small flowmeter -> CDC prototype.
I used the small flowmeter and the bubble count to very approximately match the flow rates to those from the mixer...
80sccm from the mixer ~ off the top of the small flowmeter ~ 1.9 bubbles/s (+/- 0.2)
40sccm from the mixer ~ small flowmeter measures 57 ~ 1.1 bubbles/s
estimated c. 20sccm from the mixer ~ small flowmeter measures 27 ~ 0.25 bubbles/s (+/- 0.02) - the prototype used to bubble at this rate months ago
estimated c. 10sccm from the mixer ~ small flowmeter measures 15 ~ 0.04 bubbles/s (+/- 0.02)
The non-linear correspondence between flowmeter and bubble rate implies that the prototype is leaking at or below 40sccm.
1850V, amplitude (left) and energy (right)
1950V, amplitude (left) and energy (right)
2050V, amplitude (left) and energy (right)