RE: Ion Chamber

[James.P.Revels@ucm.com]

With the new generation ion chambers, RSO-50E and RO-20, which incorporate
digital circuitry there are no more moving magnet arms, or cams that can
fail.  They are also constructed with chamber densities at 1000 mg/cm2,
which meets the 1994 revision to Reg Guide 8.34 for DEDE.  The reason for
the range problems on the earlier Bicron's was due to the slipping of the
cam on the switch shaft.  Eberline's design utilized a flat side to the
switch shaft to prevent the complete rotation of the shaft without moving
the magnet.  Eberline did modify the RO-2 by drilling into the shaft and
placing the set screw at that point to prevent any slipping.  Bicron
corrected their problem, but I do not recall how they did it.

> -----Original Message-----
> From:	Glen.Vickers@ucm.com [SMTP:Glen.Vickers@ucm.com]
> Sent:	Thursday, March 04, 1999 6:59 AM
> To:	Multiple recipients of list
> Subject:	RE: Ion Chamber
> 
> As far as the technical bulletin, I believe I there was an NRC IE notice
> ~90-44.  I have not read the bulletin myself but have read a synopsis from
> our corrective actions program.  I believe the problem had to do with a
> magnetic switch arm and a reed switch.  The result would be a significant
> under-response of the instrument.  This was associated with the rotary
> range
> switch.  I believe some of the models mentioned were the RO-2, RO-20,
> RSO-5,
> and RSO-50.
> 
> We have used used the RO-2 for many years and are now starting to go to
> RSO-50E models.  The RO-2 models have paid for themselves many times over.
> Instruments often get treated a little rough in a power plant environment,
> but they seem to have held up well.  I don't have enough data to determine
> the durability of the RSO-50E, but it does seem like it should hold up
> quite
> well also.
> 
> Sincerely,
> Glen Vickers
> glen.vickers@ucm.com
> 
> 	-----Original Message-----
> 	From:	Steve Frantz [SMTP:sfrantz@aone.com]
> 	Sent:	Wednesday, March 03, 1999 5:45 PM
> 	To:	Multiple recipients of list
> 	Subject:	Ion Chamber
> 
> 	We're using Eberline RO-2's and have very few problems as long as we
> 	remember to turn the knob slowly (see technical bulletin) and bake
> them
> 	periodically. The RO-20's may not have the same switch problem.
> 
> 	We use a lot of Ludlum GM tubes and love them, but I haven't tried
> one
> 	of their ion chambers. Our Model 19 works like a charm.
> 
> 	We can't keep the Victoreen 450s working. They are mostly in storage
> 	now.
> 
> 	My opinion only.
> 
> 	Stephen Frantz
> 	Reed College Reactor
> 	3203 SE Woodstock Blvd.
> 	Portland, Oregon 97202
> 	503 777-7222
> 	fax: 503 777-7274
> 	mailto: sfrantz@reed.edu
> 
> 
> 
> 	
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