[ RadSafe ] "war stories" re: SEM radiation issues?

[Ted de Castro]

On 10/28/2016 11:19 AM, KARAM, PHILIP wrote:
> Well - they ARE radiation-generating devices.

But NOT external to a contiguous vacuum - ESSENTIALLY no more of a 
radiation generating device than an old CRT  black and white TV set!  
CERTAINLY less than the old COLOR CRT TV's.


Thanks for the experience feedback - matches with my own experience.

Actually I've only ever seen leakage on ANY EM!  Both TEM:  One a very 
old (1948 I recall) unit with about 100 mR/hr leakage at the top of the 
column (I saw this in the early 70's), The other a 100/100 TEM with a 
special modification to the bottom of the chamber to allow it to flip 
out of the way to attached an accessory device --- which of course was 
NOT attached (seen in the early 80's).

>   Some states look at the strict definition and decide to regulate them; some states look at the dose rates and decide not to. I have never seen any dose rates that are regulatorily significant - I'm sure there might be some older units where you can get a reading, but I've never seen one. What I worried about was the x-ray diffractometers - SEMs (and TEMs) were far down on my list of priorities.
>
> Andy
>
> P. Andrew Karam, PhD, CHP
> NYPD Counterterrorism Division
> (718) 615-7055 (desk)
> (646) 879-5268 (mobile)
>
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Ted de Castro
> Sent: Friday, October 28, 2016 2:07 PM
> To: The International Radiation Protection (Health Physics) Mailing List
> Subject: [ RadSafe ] "war stories" re: SEM radiation issues?
>
> Does anyone have or is able to point to ANY radiation incidents involving SEMs??
>
> Considering the SEMs I've had experience with - I can't imagine such.  I mean low kV and low beam current less than that of the largest old CRT Black and White TV set!!  Also in the units I've seen the sample area was in vacuum contiguous with the x-ray source - thus when access is possible there is no vacuum and no vacuum - no x-ray - the best interlock possible.
>
> So - has anyone experienced anything different??  There MUST be SOME reason that they require a State License.
>
> Thanks
>
> Ted de Castro
>
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