RE: Cal Range Question

["Lavera, Ron" <Ron.Lavera@nypa.gov>]

Mr. Muldune

J.L. Shepherd sells a "cal range" that is essentially a lead shielded box
with attenuators.  They provide "certification" with the range.  If this is
the type of range that you have, then you need to be aware that there will
be considerable scatter radiation inside the box, which will have a
different energy spectrum than the primary beam.  The energy difference may
cause erroneous instrument readings,  for different types of instruments.
You may want to look at the HPS Laboratory Accreditation program for
portable instrument calibrations.

...   mine and mine alone ....

Ron LaVera
Lavera.r@nypa.gov

		-----Original Message-----
		From:	Patrick Muldoon [mailto:pmuldoon@mail.arc.nasa.gov]
		Sent:	Wednesday, July 14, 1999 4:46 PM
		To:	Multiple recipients of list
		Subject:	Cal Range Question

		Radsafers:

		I am setting-up a cal range using a Cs-137 source from J.L.
Shepherd.  The
		source is certified to be calibrated using National Bureau
of Standards
		traceable Roentgen meters with an accuracy of +/- 5%.

		My thinking is since the source is certified, all I should
need to do is
		calculate the expected dose rates and convenient distances
(already did
		this) and then check the meters at these distances both with
shielding
		half-way between the source and instrument and without to
account for
		scatter and background (similar to the set-up in Shapiro).  

		I have also heard that you should set-up your range and then
use a
		certified meter to check the dose rates at the different
distances.  Is
		this really necessary if you have a certified source?  I see
how it would
		be nice, but it seems like a bit of overkill.

		Patrick Muldoon, CHP
		pmuldoon@mail.arc.nasa.gov

	
************************************************************************
		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