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Re: Fukushima Soil

Posted: 21 May 2019, 20:56
by miree
Go-Figure wrote:
21 May 2019, 07:26
luuk wrote:
21 May 2019, 03:18
So the simple conclusion is: that it will not be possible without the use of a special high resolution crystal to really separate these two peaks, so just a small bump on the edge is all you can detect.
Luuk
Yeah, after a 18 hours measurement + roughly as much for background I know by now that that peak is beyond my reach and Peter's result is a further confirmation of it.
Today was very busy but I will post some other data from this test shortly.
Hello, I just want to add to the discussion that it is very easy to separate 137Cs and 134Cs when using 2 Detectors and measure a coincidence matrix. (See here https://www.gammaspectacular.com/phpBB3 ... =397#p2044 )
137Cs emits only a single gamma ray, while 134Cs emits gamma ray cascades. Consequently 137Cs will not show up in the conincidence matrix at all.

Michael

Re: Fukushima Soil

Posted: 14 Jun 2019, 22:41
by MartinM
Guys, there's just one problematic assumption you make. You take the date of 3/11/2011 as the date when those isotopes were created.
But this is not true - the material existed in the reactor for quite some time (could even be a few years). It was just expelled from the reactor in March 2011 (actually a few days after the earthquake/tsunami depending on which reactor it was).
The exact 'creation date' is impossible (Steven note the "impossible" ;-) to determine. Depends on refueling cycles and it's for sure a mixture of isotopes created at different times. The only thing that can be assumed is that it's not younger than 3/11/2011.

Re: Fukushima Soil

Posted: 16 Jun 2019, 03:25
by Go-Figure
MartinM wrote:
14 Jun 2019, 22:41
Guys, there's just one problematic assumption you make. You take the date of 3/11/2011 as the date when those isotopes were created.
But this is not true - the material existed in the reactor for quite some time (could even be a few years). It was just expelled from the reactor in March 2011 (actually a few days after the earthquake/tsunami depending on which reactor it was).
The exact 'creation date' is impossible (Steven note the "impossible" ;-) to determine. Depends on refueling cycles and it's for sure a mixture of isotopes created at different times. The only thing that can be assumed is that it's not younger than 3/11/2011.
Hi Martin,
yeah, of course nobody can tell exactly when the material was created by fission inside the reactor.
What we tried to do at the beginning of this thread was to go back in time since March 11 in terms of relative ratio between Cs137 and Cs134, and I think when Steven talked about "initial state" he meant the relative ratio of the two isotopes at the time they were released into the atmosphere, which we assumed to be March 11, but it could be a few days later since the release of radionuclides from the power station didn't just happen on March 11, but over several days and according to this book I am reading it peaked on March 15.

https://books.google.it/books/about/Rad ... &q&f=false