From: Peter R Hobson [Peter.Hobson@brunel.ac.uk]
Sent: 02 May 2001 10:41
To: Bruce Kennedy; Robert Brown; Cockerill David
Subject: RIE irradiated tube data

Hello Bob, Bruce, Dave

I am not sure that I can conclude all that much from the tube irradiation
tests, other than I see no obvious effects that I can correlate with dose.
I have some qualitative feeling that the anode current fluctuations (i.e.
variation in DMM reading over a period of  a few seconds) was greater in
the second irradiation that in the first (for both tubes). The measured
cathode currents were, however very stable.

Probably we should try to measure the noise spectrum during "realistic"
dose-rate tests, though I am a little skeptical about what I will conclude
given the very long cable runs from the cell to the nearest ADC.

Basically I think that AS FAR AS AVERAGE performance data is concerned we
don't see any problem up to about 10 kGy. I am sending the tubes back
today for Bruce to evaluate in the RAL 1.7T system.

Peter
 ********************************************************

Dr Peter R Hobson
Reader, Department of Electronic and Computer Engineering
Brunel University,  Uxbridge UB8 3PH   G.B.

Telephone: (0)1895 203203      FAX: (0)1895 272391