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RE: Floor monitors and a wish list
You've only solved half of the wish list - the commercially available floor
trolley. As indicated, I had one custom made for my LB-122 system almost a
decade ago.
The other (more important) part of the wish list was for a medium to large
detector (like the NE GP13A Caesium Iodide) with a much higher intrinsic
detection efficiency for gamma emitters than any gas-filled detector. The
detectors you mentioned are all gas-filled. I trust the calculated results
much more when they are based on 2-digit detection efficiencies (i.e. 20%
vs. 0.2%) for the radionuclides my people are using.
So what can you do for the other half of my list?
Karin Gordon
Radiation Safety Officer
Health Sciences Centre
GC-214, 820 Sherbrook Street
Winnipeg,
Manitoba
Canada R3A 1R9
phone: (204) 787-2903
fax: (204) 787-1313
e-mail: KGordon@hsc.mb.ca
> ----------
> From: Bly, Richard[SMTP:Richard_Bly@egginc.com]
> Sent: Friday, September 10, 1999 12:50 PM
> To: Multiple recipients of list
> Subject: RE: Floor monitors and a wish list
>
> Your wish is our command!!!
> Berthold has developed an LB 165 - for beta/gamma with sealed Xenon
> detector
> and a LB 166 for alpha/beta with an on-board P-10 gas cylinder. Both have
> active areas of 2000 square cm. The electronic module is the LB 123. It
> is
> mounted to a three wheel trolley which is height adjustable from 6mm to
> 18mm.
> Call 1-800-251-9750 US
> 49-7081-177-0 Germany
> or email: INFO_BERTHOLD@egginc.com
>
> -----Original Message-----
> From: Karin Gordon [mailto:KGordon@exchange.hsc.mb.ca]
> Sent: Friday, September 10, 1999 1:28 PM
> To: Multiple recipients of list
> Subject: RE: Floor monitors and a wish list
>
>
> About 8 years ago, my hospital radiation safey office purchased a Berthold
> LB-122 contamination monitoring instrument which employs a 12 x 18 cm
> xenon-filled proportional detector (very good intrinsic detection
> efficiency
> for betas, much less so for gammas). The detector is connected to
> electonics featuring a microprocessor with a menu of 20 different
> radionuclides. The microprocessor instantly converts raw count data -
> factoring in automatic background subtract and correction for specific
> radionuclide detection efficiency - and displays contamination levels in
> Bq/cm.
>
> (We Canadians have been using SI units for about 20 years, so I've been
> bemused by all the fuss on the recent - hopefully dead, thread).
>
> . The instrument works very well for workplace contamination surveys -
> but
> I (like many others) find that careful and thorough direct monitoring for
> floor contamination is certainly a physical challenge to back and thigh
> muscles - a sustained deep squat is ergonomically difficult. I believe the
> end result is that because of the discomfort factor, most people tend to
> do
> a much more thorough monitoring of countertops than floors, so a lot of
> trackable contamination is missed.
>
> So I requested that Labserco (the since disbanded Canadian vendor) provide
> me with a floor-sweeper assembly which would hold two of the Berthold
> detectors (combined detector surface 24 x 18 cm) connected to a single
> set
> of instrument electronics. They collaborated with me on the design and
> built quite a spiffy custom unit featuring some Pb shielding of the top
> and
> sides of the detector cradle (electronics are mounted on closed top
> surface
> of the cradle) and a telescoping handle. Monitoring of floor
> contamination
> is now a breeze.
>
> My workload includes radiopharmacy, nuclear medicine and biomedical
> research
> laboratories, so I am dealing with a full spectrum of beta emitters - from
> 150 KeV to over 2 MeV. The gamma energies we are dealing with mostly
> fall
> between 25 and 400 KeV. Any proportional counter (because it is
> gas-filled
> ) has a relatively lousy intrinsic detection efficiency for gamma rays -
> usually less than 1%. I would like to see a contamination monitoring
> instrument that combined the same sort of microprocessor / electronics /
> display features as the Berthold system with a similar large size detector
> which has a much higher intrinsic detection efficiency for gammas in that
> energy range, without losing detection efficiency for betas. One detector
> comes to mind - the GP13A caesium iodide manufactured by Nuclear
> Enterprises (recently taken over by Bicron) which has quite decent
> detection efficiencies for betas and gammas in the energy ranges mentioned
> above.
>
> I should mention that in my experience the inspectors from the Canadian
> AECB
> regulatory authority insist that licencee staff must be able to instantly
> correlate instrument readout (CPS or CPM) to actual contamination level
> (Bq/cm).
>
> Any instrument manufacturer who can offer a combination of the slick
> electronics (Berthold is just one, I know there are others) linked to a
> detector sensitive to betas AND gammas in the medical environment will
> certainly get a lot of business. And being able to put the hand-held
> instrument into an optional floor sweeper assembly would make the product
> even more appealing.
>
> The Berthold LB122 has since been replaced by the LB-123 - more bells
> and
> whistles in the electronics, and with more possibility of exchanging
> detectors - I'm not sure if the LB-123 elecrtronics could be made to work
> with the Nuclear Enterprises CsI detector, or whether one can enter into
> the
> Berthold instrument microprocessor memory the detector efficiencies
> specific
> to the radionuclides in use (crucial to calculation of surface
> contamination
> level).
>
> Are any of the vendors or manufacturers out there listening??
>
>
> Karin Gordon
> Radiation Safety Officer
> Health Sciences Centre
> GC-214, 820 Sherbrook Street
> Winnipeg,
> Manitoba
> Canada R3A 1R9
>
> phone: (204) 787-2903
> fax: (204) 787-1313
> e-mail: KGordon@hsc.mb.ca
>
>
>
> > ----------
> > From: GUILLEMOT Jean-Paul[SMTP:jpg@mgpi.com]
> > Sent: Friday, September 10, 1999 8:03 AM
> > To: Multiple recipients of list
> > Subject: Floor monitors
> >
> > I am looking for some kind of floor monitor able to detect beta &
> gammas.
> > I would like to have something mounted on wheels and if possible
> motorized
> > (think about a lawnmower with detectors instead of the blade).
> >
> > Does any one out there know about a possible vendor.
> >
> >
> > Thanks to anyone who can help.
> >
> >
> > Jean Paul GUILLEMOT
> > Customers Service Manager
> > MGP Instruments
> >
> > tel: 33 (04) 90 59 60 41
> > fax: 33 (04) 90 59 55 18
> > e-mail:jpg@mgpi.com
> >
> >
> >
> > I possibly on wheels
> >
> >
> > ************************************************************************
> > The RADSAFE Frequently Asked Questions list, archives and subscription
> > information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
> >
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> The RADSAFE Frequently Asked Questions list, archives and subscription
> information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
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information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html