[ RadSafe ] Any experience in detection of polonium onlargescalecontamination ?

Mon Dec 11 09:34:34 CST 2006

The media has touted a few times that whoever poisoned Lithinwhoozit had
to have had access to a "nuclear reactor" in order to get the PO-210.

Hhhmmmm ... Po-210 is used in some industrial applications such as
static eliminators, which are devices designed to eliminate static
electricity in processes such as rolling paper, manufacturing sheet
plastics, and spinning synthetic fibers. It is also used as a power
supply in small satellites, and in the oil industry. 

Why must the media make the whole thing sound so 'cloak and dagger'?
Murder just isn't news-worthy enough these days I guess. Now NUCLEAR
MURDER ... There's something likely to get the ratings up a bit! Reminds
me of a silly little movie they put out a while back ....Atomic Twister?

Floyd W. Flanigan B.S.Nuc.H.P.

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of John R Johnson
Sent: Monday, December 11, 2006 8:35 AM
To: Kai Kaletsch; parthasarathy k s; radsafe at radlab.nl
Subject: RE: [ RadSafe ] Any experience in detection of polonium
onlargescalecontamination ?

Thanks Kai

I'm glad to see somebody else reminding Radsafers that Po-210 is "all
around
us".

John
 _________________
John R Johnson, Ph.D.
*****
President, IDIAS, Inc
4535 West 9-Th Ave
Vancouver B. C.
V6R 2E2
(604) 222-9840
idias at interchange.ubc.ca
*****

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl]On
Behalf Of Kai Kaletsch
Sent: December 11, 2006 6:09 AM
To: parthasarathy k s; radsafe at radlab.nl
Subject: Re: [ RadSafe ] Any experience in detection of polonium on
largescalecontamination ?

You get some Po-210 on ventilation ducting used in uranium mills. (30
years
of Rn-222 decay and Pb-210 buildup.) The issue for those working on the
ducting, is inhalation and spreading the contamination around.

Airborne long-lived alpha is collected on a filter (Pall 61630 or
similar)
with a 6 - 10 hour sample pump (SKC-224 or similar) running at 2 - 3
l/min
and then allowed to decay for days to get rid of the short lived Rn-222
and
Rn-220 progeny. (If you were looking for a lot of activity, you could
get by
with a shorter sample and no decay time.)

Removable contamination is collected on a swipe (DefensAP WSD-8523 or
similar), no decay period needed. Samples (filters or swipes) are
counted in
a portable alpha counter (TM372 made by my company, or similar). An
alpha
spectrum (sorry, I don't recall a brand name. Most mines send these
samples
to an off-site lab.) is taken on a few of the samples to confirm that
you
have Po-210.

If you want to detect fixed contamination,  you probably would still use
a
probe covered in aluminized Mylar. And, yes, the average life of those
windows is approximately equal to the 1/2 life of Po-210.

Could you send me more detail on your method of depositing ZnS(Ag) with
silicone oil? Do you remember a brand name of the silicone oil...? We
have
tried a few methods for depositing ZnS(Ag) and are not 100% happy with
any
of them.

Thanks,
Kai Kaletsch
Environmental Instruments Canada Inc.

----- Original Message -----
From: "parthasarathy k s" <ksparth at yahoo.co.uk>
To: "RadSafeInst" <RadSafeInst at cableone.net>; "John R Johnson"
<idias at interchange.ubc.ca>; "David Schauer" <dschauer at usuhs.mil>;
<radsafe at radlab.nl>
Sent: Sunday, December 10, 2006 10:54 PM
Subject: [ RadSafe ] Any experience in detection of polonium on large
scalecontamination ?

Detection of polonium contamination by area monitoring has certain
difficulties. Since the range of alpha particle from Po-210 is only a
few cm
in air and the gamma emision accompanying Po decay is very feeble, how
do
you carry out large scale area monitoring?

If you are using large area alpha scintillation counters, based on Zn
S(Ag),
one of the problems is to maintain the background counting rate at a low
value.The thin (0.1 mg/square cm)aluminium covered window develops
pinholes
leading to light leaks. This results in stray counting.  We had
difficulty
in less trying circumstances. we had to replace the thin  alunmnium foil
very frequently

This story is decades old! Now there may be better instruments availble
commercially.I am an old hand and used to make large area scintillation
counters by making alpha detector foils by sprayng fine ZnS(Ag) powder
on
transparent plastic sheets coated with silicone oil. Can any one in the
list
throw some light on newer methods if any? I was told that large area air
proportional counters are available commercially. During the seventies
we
tried to develop  spark counters with limited  success.

Urine sampling etc is well developed and relatively easy though time
consuming and is not applicable in area monitoring!The UK Health
Protection
Agency must be combing large areas
Not much is known about the methods used by them.

The infamous polonium poisoning incident is worrying for those who have
to
carry out area minitoring in case some rogue elements try to spray it in
busy malls, shoping centres etc.

Regards

K.S.Parthasarathy

___________________________________________________________
Try the all-new Yahoo! Mail. "The New Version is radically easier to
use" -
The Wall Street Journal
http://uk.docs.yahoo.com/nowyoucan.html
_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood
the
RadSafe rules. These can be found at:
http://radlab.nl/radsafe/radsaferules.html

For information on how to subscribe or unsubscribe and other settings
visit:
http://radlab.nl/radsafe/

_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood
the
RadSafe rules. These can be found at:
http://radlab.nl/radsafe/radsaferules.html

For information on how to subscribe or unsubscribe and other settings
visit:
http://radlab.nl/radsafe/

_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood
the RadSafe rules. These can be found at:
http://radlab.nl/radsafe/radsaferules.html

For information on how to subscribe or unsubscribe and other settings
visit: http://radlab.nl/radsafe/