1. Tera-Pixel APS for CALICE Progress 20 th October 2006 [JC+RT]

2. PreSample Pixel Rst Vrst Preamp PreRst Buffer s.f Cpre Cin Buffer s.f RstSample Cstore Vth+ Vth- 3ns 12ns Preamp Shaper Rst VrefVref-Vth Buffer s.f PreShape Pixel

3. PreampSource Follow er ShaperComparator (in- pixel) Comparator (off- pixel) 1.8v 3uA1.1uA1.7uA0.5uA0.3uA 5.4uW2uW3uW0.9uW0.5uW Pixel Source followe r Charge (Pre)am plifier Output Source Follow er Comparator (in- pixel) Comparator (off- pixel) 1.8v 0.9uA1.3uA1.2uA1uA750nA 1.6uW2.4uW2.2uW1.8uW1.3uW PreSample Pixel 9.3μW 11.8μW

4. PreSample Pixel PreShape Pixel 250 electron hit 55mV typ. ~150ns above threshold 220uV/electron 250 electron hit 75mV typ. requires reset (150-300ns) 300uV/electron

5. PreSample Pixel PreShape Pixel Transient Noise 11mV typ at input to comparator ~ 50 electrons Transient Noise 6.9mV typ at input to comparator *√2 = 9.8mV (*√2 due to sampling) ~ 32 electrons

6. PreSample Pixel PreShape Pixel Signal/Noise optimisation Larger diode capacitance increases noise Signal/Noise optimisation Larger diode capacitance decreases signal

7. PreSample Pixel PreShape Pixel NWELL = 1.3 x 6.3 μm NWELL = 5 x 5 μm

8. PreSample Pixel PreShape Pixel Risks Cpre feedback cap Risks Cpre feedback cap >10 MIP behaviour Saturation causes pulse elongation  double hits >10 MIP behaviour Increased error in reset sample for subsequent hit Advantages Always active (no reset) No overflow (pixel recovers after saturation) Disadvantages Power NWELL S/N Mismatch Disadvantages Requires reset after hit  additional logic  dead time after hit Reset sample can contain error Pixel can saturate (overflow) Advantages Power NWELL S/N