Re: MODEL 44-116 light leak

["Paul R. Steinmeyer" <prstein@gyral.com>]

Hello Andrew,

We also use the Ludlum Model 44-116 beta scintillator, and I can offer a few
suggestions.  I confess that some of these enter very near to the realm of
superstition but they have worked for us.

1.  We always place the "Mylar only" side of the window against the detector
(so the side with the black frame is against the grill).

2.  We have coated the interior of the aluminum component that holds the grill
on with a black marker to reduce or eliminate possibility of reflected light
entering the detector area.

3.  We always put a layer of opaque tape around the metal-to-metal seam when it
is fully re-assembled.

4.  Keep in mind that you will need to wait at least a couple of hours after
making the window change before the detector "settles down" enough to see how
the fix worked (I believe Ludlum recommends "overnight.")

5.  It's always best to test the integrity of the Mylar yourself before
installing a new window; I have found that Ludlum takes great pains to ensure
their replacement windows are leak free, but shipping (and worse yet) storage
may take their toll.  Take it into a (very) dark room and shine a flashlight
from the back (right up against the window).  Any pinpricks will show up
clearly as a dot of light.

6.  Is there any possibility that either the high voltage is too high or the
input sensitivity is too low (admittedly doubtful)?

I hope this helps.  Feel free to contact me directly by phone of email if I can
be of any further assistance.

Paul R. Steinmeyer
Radiation Safety Associates, Inc.
860/228-0487
prstein@radpro.com

Andrew Astleford wrote:

> Hello,
>
> I am having trouble with our 44-116 beta scintillator probe.  I have had to
> replace the aluminized mylar window due to a tear; however, I can not get a
> good seal now.  If any of you have some experience with this I really could
> use some advice.
>
> thank you
>
> andy
>
> ___________________________________
> Andrew Astleford
> Environmental Health & Safety
> Radiation Protection Division
> University of Minnesota
> (612) 626-6940
> FAX: (612) 625-1608
> astle001@maroon.tc.umn.edu
> "Standard Disclaimer"
>
> ************************************************************************
> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html

************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html