For the present, work surfaces for three different applications were
investigated:
- Conversion surfaces for NICE style sensors
- Start surfaces for NPD style sensors
- Stop surfaces for NPD style sensors
Start surfaces should exhibit a high secondary electron yield, low
angular scattering, and a low UV sensitivity (e.g. low photo electron
yield, low UV photon reflection). Stop surfaces on the other hand
should exhibit a very high secondary electron yield with no requirements
regarding angular scattering. The most challenging surface type is
the conversion surface: high ionization yields, low UV sensitivity,
low angular scattering, predictable energy loss upon scattering, low
energy spreading, and low sputtering are the main requirements.
Ideally a surface would not change its key properties over time, would
not require routine reconditioning or special cleaning, and would
be easy to handle.
March 2001 - Martin Wieser, Physikalisches Institut, University of Berne, Switzerland
