AW: [ RadSafe ] surface emission rate,surface DPM from 27 pCi Tc-99

Franz Schönhofer franz.schoenhofer at
Fri Dec 14 12:42:39 CST 2007


Is there anybody out there who knows this person, who wants to proof that
all those excellent experts on RADSAFE are idiots?????

There is no confusion, there is no problem in translation (I think and have
been assured by many hundreds of English native speakers that my English is
excellent). The relation between the outdated, but in a few states in this
world (e.g. USA) still used "pCi" to the disintegrations per minute or
rather disintegration per second (Bq) is internationally fixed.  

There is a really terrible confusion by Mr KOFF (Finnish beer brand - short
for Synebrychoff). He seems not to know that DPM means "disintegration per
minute), which refers to the radioactive substance and is independent of any
"front working surface" (whatever this might be), any self absorption. It is
not related to any beta efficiency, not of any probe. 

Furthermore I would have hoped that Mr. KOFF knows the difference between
dpm (disintegrations per minute) and cpm (counts per minute). Obviously he
does not.  

Having worked more than thirty years on the determination of radionuclides I
can assure everybody, that there is no interest in "how many particles are
leaving the test disc", but the most important analytical question is, what
the efficiency (both chemical and counting) is in order to translate cpm
into dpm. Am I missing something? This is the task of radionuclide
determination since probably 100 years!!!! 

I would not be surprised if you would still not understand how silly your
question was and even more that you insist on your less than amateurish
opinion. I do not expect that you will refrain from those silly postings. I
do not hopte that you will bother RADSAFE in the future. 

Best regards,


Franz Schoenhofer, PhD
MinRat i.R.
Habicherg. 31/7
A-1160 Wien/Vienna

-----Ursprüngliche Nachricht-----
Von: radsafe-bounces at [mailto:radsafe-bounces at] Im Auftrag
von Geo>K0FF
Gesendet: Freitag, 14. Dezember 2007 16:39
An: Geo>K0FF; radsafe at
Betreff: [ RadSafe ] surface emission rate,surface DPM from 27 pCi Tc-99

In case there is some confusion or a problem in translation, the information

requested is the 2 pi beta emission rate from the source delineated below.

Another way of stating it is: the total number of beta particles coming from

the front working surface of the disc.

Forget about self absorption, counting error, confidence level, and 
systematic error.

This is not a trick question. To determine the beta efficiency of a probe, 
one needs to know how many particles are leaving the test disc.

Reply if you care to, to

George Dowell at

GEOelectronics at

The calculations will be posted here after a short time.

George Dowell
New London Nucleonics Lab

----- Original Message ----- 
From: "Geo>K0FF" <GEOelectronics at>
To: <radsafe at>
Sent: Tuesday, December 11, 2007 7:45 PM
Subject: [ RadSafe ] DPM from 27 pCi Tc-99

> What is the surface DPM of a 27 pCi Tc-99 electroplated disc source? The 
> substrate is stainless steel. (by calculation only please)
> George Dowell
> New London Nucleonics Lab

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