[ RadSafe ] rad monitor calibration

Dennis Quinn dqdx at aol.com
Mon Jun 2 10:26:39 CDT 2014

The beta factor should be determined for the spectrum you are interested in.
In general, a source is used that provides a known dose rate (generally
defined under 7 mg/cm2) at a specific distance.  You then place the ion
chamber at that distance (generally center of chamber), and you then have a
beta correction factor for that source in free air. So uranium may be good,
or not, depending on what energies of beta you are expecting.  The
complication is that often the source in the field is rapidly changing with
distance and the free in air beta factor may or may not apply.  A good
example is for a small source with a near contact reading with the ion
chamber.. it will result in a high correction factor because the dose on
contact with the source is much higher than that at the center of the
chamber (or average across the chamber).
Dennis Quinn

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Brent Rogers
Sent: Sunday, June 01, 2014 8:04 AM
To: ROY HERREN; The International Radiation Protection (Health Physics)
Mailing List
Subject: Re: [ RadSafe ] rad monitor calibration

On a similar vein, does anyone know for certain how the beta-factor on ion
chambers is determined?  I'm speaking of obtaining beta dose rates using
(open window - closed window) * beta factor.

Brent Rogers
Sydney Australia

Sent from my iPad

> On 1 Jun 2014, at 3:55 pm, ROY HERREN <royherren2005 at yahoo.com> wrote:
> The calibration procedures will vary depending on which specific
instrument your calibrating.  Unless you have the in-house expertise, I
highly suggest that you leave the instrument calibration to the instrument
vendor.  In any case, your instrument vendor should have provided you with
an instrument manual when you purchased each of the instruments.  Look
through the instrument manual to see if it lists any information about
instrument calibration.  Do you own an instrument calibration source?  If
so, also look up what the literature from calibration source
manufacturer/vendor provides regarding instrument calibration. 
> Roy Herren
> On , ROY HERREN <royherren2005 at yahoo.com> wrote:
> Are you specifically referring to the Rad MonitorTM instruments
manufactured by Lab Logic, see Rad-Monitors
>   Rad-Monitors  
> View on www.lablogic.com Preview by Yahoo  
> Roy Herren
> On Friday, May 30, 2014 1:18 PM, "JOHN.RICH at sargentlundy.com"
<JOHN.RICH at sargentlundy.com> wrote:
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