1.) Simulation:
3.) Readout:
5.) Test Apparatus
Student Jeremy Dobbins has return from CERN after working with
Fabio Sauli. While at CERN he built a second Qweak detector
proto-type. This proto-type has 3 GEM premplifier stages and a
trigger output line from the last GEM foil.
Second Qweak Prototype.
The gain as a function of
GEM foil potential difference has been
measured using 8 keV X-ray and 2 different gas mixtures. The 75%
Ar and 25 CO2 mixture is a standard mixture while the 70/30
mixture is a more expensive special order. At
present it is $25 for the 75/25 and $150 for the 70/30 mixture.
The detector's
response in a typical 2 cm x 2cm region was measured. The
detector output fluctuates by up to 10% for the 8 keV collimated
X-ray dose. Summing 16 readout lines and amplifying by a factor
of 5 results in a 450-500 mV output (so one unamplified line would
be around 5 mV into the Helix board)
