Preamp 4: Quick look at cosmic data with reduced fADC range

• The cosmic data below were obtained with the input range of the fADCs reduced.

• The fADCs now accept signals from 50mV to 600 mV (approximately) - this is half of the previous range. We adjusted the shaper output correspondingly, to put the lowest baseline voltage at around 80 mV (it varies from straw to straw).

• Each run was for around 20 hours or less.

• The following show untracked data (hits in multiple straws are not required) so that they can be compared to the earlier spectra (remembering that the fADC range is now half of that used previously):

1750V (19.5h) amplitude (left) and energy (right)

new preamp, new fadc range (=1/2 old one), amplitudes, 50/50 Ar/CO2, 1750V

new preamp, new fadc range (=1/2 old one) , energy, 50/50 Ar/CO2, 1750V

1850V (24h) amplitude (left) and energy (right)

new preamp, new fadc range (=1/2 old one), amplitudes, 50/50 Ar/CO2, 1850V

new preamp, new fadc range (=1/2 old one) , energy, 50/50 Ar/CO2, 1850V

1950V (18h?) amplitude (left) and energy (right)

new preamp, new fadc range (=1/2 old one), amplitudes, 50/50 Ar/CO2, 1950V

new preamp, new fadc range (=1/2 old one) , energy, 50/50 Ar/CO2, 1950V

And with the original preamp and ADC range for comparison: 1950V - amplitude (left) and energy (right)

old preamp, old fADC range, amplitudes, 50/50 Ar/CO2, 1950V

old preamp, old fADC range, energy, 50/50 Ar/CO2, 1950V

• Finally, a low statistics efficiency plot obtained with these new data (new preamp, new fADC range) for channel 7, which had the largest number of tracks going through it:

new preamp, new fadc range (=1/2 old one), Efficiency plot or HV curve, 50/50 Ar/CO2

This looks very promising but it would be nice to do it with more statistics and data points...