Quizlet for you

Share your spectra and discuss their features here
User avatar
Milos
Posts: 14
Joined: 28 Jul 2019, 19:17

Quizlet for you

Post by Milos » 20 Sep 2026, 04:24

Hi guys,

Today I have a Quizlet for you, see the spectrum below, please. What we are looking at is pretty obvious, I think; however, the question is: what material is it?

A) Calibration source
B) Old vacuum tube
C) Vintage surge protector
D) Mushroom
E) Lichen
F) Burnout nuclear fuel speck from Chernobyl (size 0.2 mm)

So, what do you think? :-) ...

Image

User avatar
Svilen
Posts: 190
Joined: 23 Sep 2016, 04:25

Re: Quizlet for you

Post by Svilen » 20 Sep 2026, 04:39

Since it is a clean 137Cs spectrum with a prominent barium x-ray peak and no clearly visible additional fission-product lines, I would guess that it is a calibration source. However, the sample cannot be clearly determined from the spectrum alone :)

User avatar
Milos
Posts: 14
Joined: 28 Jul 2019, 19:17

Re: Quizlet for you

Post by Milos » 21 Sep 2026, 06:31

Good suggestion Svilen :-), then F) can be ruled out. Anyone else?

Rob Tayloe
Posts: 179
Joined: 10 Nov 2020, 12:00

Re: Quizlet for you

Post by Rob Tayloe » 24 Sep 2026, 23:20

The spectrum shown above looks pretty clean. My guess would be a calibration source also. In the link below are some spectra from some actual fuel "specks" collected outside the Chernobyl facility and some discussion about detection of Eu-154 and Am-241.

https://fusor.net/board/viewtopic.php?t=6272

Below is a link to a YouTube video of a gamma spectra from NaI of a "speck" of Chernobyl fuel found outside the facility.

https://www.youtube.com/watch?v=LRMDc6zeVWQ

User avatar
Milos
Posts: 14
Joined: 28 Jul 2019, 19:17

Re: Quizlet for you

Post by Milos » 05 Oct 2026, 09:27

OK, I will tell you the correct answer to the Quizlet, and you won't believe it. It is a single boletus mushroom with a dry weight of 37 g from Gävle, Sweden.

During our trip to the far north, we were driving back to our country near Gävle. I found out that this area was one of the most contaminated in Sweden by the Chernobyl disaster, so I decided to make a stop there and collect some soil and mushroom samples. The spectrum below compares this sample with mushrooms collected in the forest where I live in the Czech Republic. The dry weight of the mushrooms from our forest used for the measurement was actually twice as high (72 g), but still, the signal is order of magnitude weaker.

The conclusion is that consuming mushrooms from such heavily affected areas could pose a significant health risk, I think.

Image

Daniel
Posts: 8
Joined: 26 Aug 2026, 10:28

Re: Quizlet for you

Post by Daniel » 05 Oct 2026, 12:01

Would there also be a radium peak at 186Kev?

User avatar
Svilen
Posts: 190
Joined: 23 Sep 2016, 04:25

Re: Quizlet for you

Post by Svilen » 05 Oct 2026, 18:15

Impressive mushroom contamination, Milos. Nice find!
Daniel, if I don't get you wrong and you mean the peak visible on the yellow graph - this is from backscatter.