Re: Be-7 detections in ambient air samples

[Franz Schoenhofer <schoenho@via.at>]

At 10:10 05.03.1999 -0600, you wrote:
>During routine gamma analyis of high volume particulate air samples
(originally looking for Co-60 and Cs-134), our laboratory has detected
somewhat elevated readings for Be-7.
>
>The only natural source we've been able to fing would be from upper
atmosphere interactions with N and O.  Does anyone have any information
regarding the presence of Be-7 in ambient air samples, such as possible
sources, "normal concentrations", etc.?
...................................................

Yes, you are right, it comes from the upper atmosphere where it is
generated by cosmic rays. Be-7 is present in any aerosol sample, otherwise
your analysis would be wrong. A "normal concentration" cannot be given,
because there is a very pronounced seasonal variation, depending also on
the latitude and on the solar activity. If you are interested I could on
Monday look up the concentrations and the range we usually find in Austria.

Franz


Franz Schoenhofer
Habicherg. 31/7
A-1160 Vienna
Austria
Tel.: +43-1-495 53 08
Fax.: same number
mobile phone: +43-664-338 0 333
e-mail: schoenho@via.at

Office:
Hofrat Dr. Franz Schönhofer
Federal Institute for Food Control and Research
Department of Radiochemistry
Kinderspitalg. 15
A-1095 Vienna
Austria
Tel.: +43-1-40 490 27820
e-mail: schoenhofer@baluf.via.at
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