29 Jul 2008 Paul Dauncey 1

Some sensor noise measurements

Paul Dauncey

29 Jul 2008 Paul Dauncey 2

Dependence on settings• With (solid) and without (dashed) strong desk lamp

• Higher noise unlikely to be due to light leaks

29 Jul 2008 Paul Dauncey 3

PCB jumpers• Set J23 (top) and J24 (bottom) to alternate position (left) or remove (right)

29 Jul 2008 Paul Dauncey 4

Relook at i12CompBias2 • Previously saw a significant change to S/N; noise from comparator?

• Recheck with a different pixel

• Use laser to give fixed signal size; vary i12CompBias2

• Different colours are different groups of runs• Blue was steps of 4TU, pink and yellow 1TU

RMS below 1TU

29 Jul 2008 Paul Dauncey 5

Signal/Noise ratio• Take ratio to get signal/noise

• Seems like a factor ~3 improvement in S/N…

• ...but could not see a Fe55 signal with a brief run