Krakow gas gainmeasurements

Bartosz Mindur

Faculty of Physics and Applied Computer ScienceAGH University of Science and Technology

RD51 mini-week, WG4 session, 05-12-2012

Bartosz Mindur Krakow gas gain measurements

Measurement test bench

Gas distribution system

Pumping station (below notseen)

Valve for external gasbottles connection (rightside)

Two housings for chambers(left side - partially seen)

HV power supply (i.e.CAEN)

Keithley 6485 Picoammeter(10 fA resolution)

Bartosz Mindur Krakow gas gain measurements

Chambers

Two chambers insideseparate housings

Made out of copperBeryllium windowExternal φ=28 mmInternal φ=25 mmLength about 250 mmAnode wire – gold platedtungsten

φ=100 µmφ=48 µm

Independent HV, currentreadout and gas supply

Bartosz Mindur Krakow gas gain measurements

Minimization of dark current

Problems with dark currentin previous setup

Solution guarding rings

Eliminates current flow fromcathode to anode troughinsulators

Slightly more complicatedsolution – see picture

Bartosz Mindur Krakow gas gain measurements

Conclusions

New setup (almost) ready

Vacuum tight

Chambers ready (not yet connected to HV)Soon measurements will start

First with Ar/CO2CO2 concentrations <5% and >30%Pressure (absolute) for the moment <2.5 Bar

Other gas mixture measurements we can define later (whenwe see results from Ar/CO2)

Bartosz Mindur Krakow gas gain measurements

Thank you for your attention!

Bartosz Mindur Krakow gas gain measurements