Re: Cutie-pie ion chamber

[Chris Alston <alstonc@odrge.odr.georgetown.edu>]

Is there any special reason you need the QTPi geometry specifically? I
assume that you're implying that you want a removable buildup cap so that
you can measure beta doses, and, without having to apply correction factors,
low-E photonic fields. Anyway, firstly, don't buy any such instrument unless
it has an integrative mode. Then, I think that someone recommended the
Keithley 36105, or whatever the numerical designation is, these days. It's
certainly a wonderful instrument; it's extremely fast, has a
(trigger-controlled) backlit digital display, and only three ranges
(0-200mR, 0-2R, 0-20R). It's especially good for xray work and patient
surveys. But it's at least US$2500 (last I knew) and it's not delicate, but
not super-rugged, either. If you do get it, make sure that it's the one with
(I reiterate) an integrating mode, and also the folding legs, so that it can
stand by itsself. You should consider the Victoreen 450B, though. The
chamber is internal to the meter's case, rather than extending from it, so
it is not a QTPi. There's a sliding panel to remove the  buildup layer and
expose the primary window (aluminized Mylar). It's all digital,
auto-ranging, etc., with ranges to 0-50R. Even the lighting function is
automatic, now. It's about as rugged as such an instrument can be, and costs
about half that of the Keithley.

Good luck
chris alston

At 08:15  07/23/98 -0500, you wrote:
>Does anyone have a recommendation for a currently available "cutie-pie"
>style ion chamber?  I need to replace some aging Eberline RO-3s and have
>been told by an Eberline representative that they are not eager to make
>any RO-3, RO-3C units.
>
>Manufacturers may contact me directly.  I am really interested in any
>operational experience that users may care to share.
>
>Mike Lewandowski
>3M Company
>(651) 737-4452
>mailto:MALewandowski@MMM.com
>
>
>
Chris Alston
alstonc@odrge.odr.georgetown.edu
I am not here a representative of my employer.