CCD
Features of CCD
- Extremely low noise :
~40e-(less than10e-with slow scan)
- Thin active region :
Less probability of X-ray conversion.
Similar output both for normal and inclined incident particles.
Less hit occupancy for inclined particles.
- Most of active layer is NOT depleted :
Excelent spatial resolution can be achieved for normal incident particles
owing to charge sharing by difusion.
- Thin wafer : limited by mechanical strength.
Less multiple scattering.
- Simple structure :
Small pixel size and large chip size can be made.
- Slow readout : Not a serious problem for JLC.
- Radiation damage :
Because collected charge is transferred by few cm, the effect of
charge trapping becomes a serious problem after radiation.