Subject: RE: Raith: please don't use 15-20.9KV or 23-30KV
From: "Ji-Won Son" <>
Date: Wed, 21 Apr 2004 21:18:18 -0700

 Wed, 21 Apr 2004 21:18:18 -0700
Hi Mark,

Thank you for the message. But one thing which is not clear to me is that
why the range between 20.1-20.9 is included in the dangerous range. As far
as I know, the most dangerous range is 15 to 20 kV, and 23kV and higher
(where the actual acc. voltage is higher than 23 kV). Does anyone experience
problem in the range of 20.1 to 20.9kV? 

I would appreciate your help. Thank you.
Ji-Won Son
Office: (650) 723-4940
Fax: (650) 725-3459

-----Original Message-----
From: Mark Topinka [] 
Sent: Wednesday, April 21, 2004 8:01 PM
Subject: Raith: please don't use 15-20.9KV or 23-30KV

(in other words, 0-15KV is ok and 21-23KV are probably ok, but DO NOT set 
it to 15-20.9KV or 23-30KV : these ranges cause intermittent EHT trips, 
which can occasionally turn into the more serious and dreading "arc", which 
can ultimately seriously damage the instrument)   Sylvia had problems with 
repeated EHT trips (even after a LONG pumpdown) today and we do not want a 
repeat of what happened earlier this year (right!?) until we sort out what 
exactly is going on.  -Mark