[ RadSafe ] Automobile Air Filter Spectrum (was hot particles)

Busby, Chris C.Busby at ulster.ac.uk
Tue Jun 28 12:43:16 CDT 2011

Yes. I also would be cautious about Am241, that peak could be in the lead shielding Xray region. However, I now have the other filters up and running and so I can play about with them, autoradiography, alpha spectroscopy, CR39 etc. They all show the stuff on this spectrum you are analysing. NaI spectra can be non linear as Im sure you know. Ill add some Am241 from a smoke detectro and see where it comes. Whats that at 110 though. Any guesses?

-----Original Message-----
From: radsafe-bounces at agni.phys.iit.edu on behalf of Thompson, Dewey L
Sent: Tue 28/06/2011 14:13
To: The International Radiation Protection (Health Physics) Mailing	List
Subject: Re: [ RadSafe ] Automobile Air Filter Spectrum (was hot particles)
I for one would have serious reservations about calling Am-241 in this spectrum.  I would need to see the energy calibration and look at the offset for the region around 60 Kev.  There are a lot of KLM X-Rays flashing about, which would really muddy the spectrum down there, and you would need to subtract the confounders prior to estimating any activity of Am-241, which just might leave.....Nothing.

If we assume the cursor is on the Cs-137 line, it appears that the offset for Cs-137 is in the neighborhood of 8 Kev, meaning the energy calibration is wildly imprecise.   To be sure, the energy offset will reduce with the photon energy, however I wonder if 3 Kev offset is reasonable given the apparent offset for the 662 Kev line. 

IF we accept the cursor is on the 662 Kev energy (Cs-137), then Cs-134 is a good bet, the 605 and 796 appear to be indicated, although I believe Cs-134 does have some stuff in the 570 Kev range and I'm thinking I would expect to see higher background in that area. 

Since the energy calibration offsets are not specified, it is not clear on those peaks questioned at 120 and 240 Kev what the energy estimate really is.  It would be pointless to speculate.

Both baby peak (120 Kev) and the thing in the middle (240 Kev) have poor resolution, neither is likely from a single photon.  


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-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Jeff Terry
Sent: Saturday, June 25, 2011 11:19 PM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Hot particles on automobile air filters

Hi All, 

Please remember that the list only accepts pdf files. If you want to have your files sent through to the list, then you must convert them to pdf before submission. If you do not, then they get bounced to me and I just don't have time to convert them all to pdfs for everyone. 

I won't get in the habit of converting these and posting them. I have to look through and find the bounced file, convert it, and repost it. Consider this a one time effort on my part. Buy a Mac and just save everything as a pdf while in print mode, easy. 



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