Re: Commercial Uses of Pm-147

[Schoenhofer <schoenho@via.at>]

At 11:19 1996-07-10 -0500, you wrote:
>     Fellow Radsafers,
>     
>     We recently have had a spill in a cold lab where the isotope was 
>     identified as pure Pm-147 (microcurie quantities).  This isotope is 
>     not part of our normal inventory, except as a minor constituent in 
>     fission products.  Does anyone know of commercial products that use 
>     this particular isotope?
>     
>     Lawrence Burke
>     Health Physicist
>     Argonne National Lab - West
>     (208)-533-7078
>     (208)-533-7344 Fax
>     lawrence.burke@anl.gov
>
>=======================================================================0

Like so many other radsafers I think that the commercial application of
Pm-147 was mostly in the watch industry. From William Kolbs book "Living
with radiation - the first hundred years" (itīs a very good book for
everybody interested in the history of use of radionuclides!) I read the
information that after World War II for a short time Sr-90 was used in
timepieces, but quickly replaced by Pm-147 and tritium. Pm-147 has the
drawback of relatively short half live and higher energy than tritium.
Tritium has the draw back of easy diffusion from luminous paint and
incorporation into the body, especially when plastic cases are used. We
found in a volunteer 3000 Bq tritum per liter urine after equilibrium had
been established. This gives a neglectable dose, but still it is not
necessary to accumulate it. The glass capillaries filled with tritium gas
and a phosphor may break. In William Kolbs book it is also mentioned that
Pm-147 has been used in some applications as a ionizing source. 

Let me tell you a non-scientific story - but related to radiation protection:

One of my children came many, many years ago home from kindergarten and he
was proud that they had done a very interesting work during the day - they
had disassembled a large alarmclock. By chance he had been allowed to take
the piece with the luminous dials home. I checked it - it was radioactive,
but it was neither tritium nor radium - the spectrum on our germanium
detectors was that of a beta emitter. I took the liberty to attribute it to
Pm-147 because of plausibility reasons. - For small children it might not be
advisable to let them play with such old alarm clocks.

What I wonder finally, is, whether you could find any small pieces of
luminous paint and how you identified it to be Pm-147.

Would not our life be boring if he had not now and then some unexpected
phenomena?

Franz Schoenhofer
Federal Institute for Food Control and Researcj
Kinderspitalg. 15
A-1095 Vienna
AUSTRIA
Schoenhofer
Habichergasse 31/7
A-1160 Wien
Tel./Fax:	+43-1-4955308
Tel.:		+43-664-3380333
e-mail:		schoenho@via.at