[ RadSafe ] Fwd: Radon Progeny affinity for Iron Oxide (rust)qqueous
parthasarathy k s
ksparth at yahoo.co.uk
Fri Sep 13 02:08:33 CDT 2013
Dear Dr Alston,
During the early 70s, I have demonstrated the accumulation of radon progeny on surfaces of decorative plastic used to line walls and on surfaces of polythene used to fabricate "phantom". I could also demonstrate that the presence of static charge on the surface aids deposition; deposition is less when the surfaces of the polythene phantom used for calibration of whole-body radioactivity monitors are covered with an aluminium foil. Foils used in wrapping food is good enough.
Rusted surface may have more surface area. I am not sure whether iron oxide is a good conductor.In all cases electrostatic charges do play an important role.Atoms of Po-218, the first decay product of radon-222 do carry a positive charge.Also most of the aerosols to which the atoms of the decay products stick are also charged. Aqueous aerosols are positively charged and carbonaceous aerosols are negatively charged. I do not have any ready references for these observations. I had some correspondence with Prof P J Lawther,the then Director,Air Pollution Unit, UK Medical Research Council on the topic
From: Chris Alston <achris1999 at gmail.com>
To: The International Radiation Protection (Health Physics) Mailing List <radsafe at health.phys.iit.edu>
Sent: Thursday, 12 September 2013, 22:33
Subject: [ RadSafe ] Fwd: Radon Progeny affinity for Iron Oxide (rust)
I cannot cite you a study or report, right off, but I can tell you,
from experience, that this is so. What's more, the metal does not
have to be rusty. With the right atmospheric conditions, painted
objects, such as trucks and automobiles, will also give spurious alpha
counts due to the accumulation of radon daughters. Actually, plastics
and neoprene can too.
The saving grace is that radon (Rn-222) progeny are gone in a few
hours; the same is not true of thoron (Rn-220) daughters, where you
get actual ingrowth of longer half-lived progeny.
---------- Forwarded message ----------
From: dcoble tds.net <dcoble at tds.net>
Date: Thu, Sep 12, 2013 at 11:58 AM
Subject: [ RadSafe ] Radon Progeny affinity for Iron Oxide (rust)
To: "The International Radiation Protection (Health Physics) Mailing
List" <radsafe at health.phys.iit.edu>
I am inquiring if there has been a study or report that supports the theory
that Radon Progeny has an affinity for certain types of metal e.g., (rusty
steel, galvanized steel, etc.)? If so, can someone point me in the right
direction or provide me a copy of the study or report?
Most field Technicians in the environmental remediation arena are familiar
with or have experienced at some point increased low level alpha counts
with hand held instrumentation when trying to release metal objects for
unrestricted use. I personally have experienced it when surveying steel.
Painted portions would be at or below background while rusty sections of
the same piece of steel would produce alpha counts from 2 to 10 times
background. Considering free air background ranged from 0 to 2 cpm.
Historical assessment of the area the steel came from revealed no known
reason for the metal to be contaminated. Surveys of the metal were
required due to decommissioning plans or site specific procedures and were
established to be conservative. Additionally, resurveys or the same area 2
or 3 days later would not indicate the presence of alpha emitters. This
leads me to believe that the culprit is Radon Progeny.
Thanks in advance for any help that you may provide.
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