next up previous contents
Next: Conclusion Up: SILICON DETECTORS Previous: Readout frequency

Radiation damage

Running at full proton intensity, the radiation damage induced on the silicon counters is certainly a serious issue.

Assuming 100 effective days of run time, with 5000 spills per day at a beam intensity of 5 tex2html_wrap_inline2708 10 tex2html_wrap_inline2648 ptc/sec, one can roughly expect 5 tex2html_wrap_inline2708 10 tex2html_wrap_inline3208 -10 tex2html_wrap_inline3210 ptc/cm tex2html_wrap_inline2256 as a maximum upper limit.

With such a high particle flux, it will be tex2html_wrap_inline3214 to replace the detectors after every full year of run. In the meanwhile the counters will have to be operated at very low temperature ( tex2html_wrap_inline2848 0 tex2html_wrap_inline3218 C) because of the very high leakage current which will be developed (general informations about radiation damage on single sided silicon microstrip detectors can be found in reference [30]).

In view of the frequent change of the counters, we plan to mount them in such a way that only the silicon will be replaced while the electronics can be re-used. For example a silicon piece with metal lines and several bonding pads per line can be used as a bridge between the readout chips and the changeable silicon planes.

As already mentioned in the proposal, the possibility of diamond detectors is also taken into account. They would have the clear advantage of much better radiation resistance, lower load capacitance, low leakage currents. On the other side still more developments are needed to make these detectors a safe technology.

We are in contact with the RD42 Collaboration to follow the developments in progress and acquire some basic experience with this kind of detectors.

Lars Schmitt
Wed May 22 16:44:09 METDST 1996