Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Am241 and beta radiation
vmelkon
National Hazard
****




Posts: 669
Registered: 25-11-2011
Location: Canada
Member Is Offline

Mood: autoerotic asphyxiation

[*] posted on 2-8-2019 at 07:29
Am241 and beta radiation


I am talking about Am241 from smoke detectors.
I have not opened brand new smoke alarms. I have only opened ones that are ~20 y old and not working well. My geiger counter can detect beta + gamma. It is one of those old CDV 700.

If I place the geiger's probe right on the Am241 button, I get about 1250 CPM. If I close the metal probe, the metal blocks the beta particles. It only counts gamma. I think it goes down to 50 CPM (I don't remember).

Does it make sense that an Am241 button emits beta particles (electron or positrons?). Or is it all gamma?

Am241 decays via alpha.
The dp is Np237 which also decays via alpha and has a super long half-life.
So, essentially, there should not be any beta emitters unless there is some impurity in these Am241 buttons.




Signature ==== Is this my youtube page? https://www.youtube.com/watch?v=tA5PYtul5aU
We must attach the electrodes of knowledge to the nipples of ignorance and give a few good jolts.
Yes my evolutionary friends. We are all homos here.
View user's profile View All Posts By User
Ubya
International Hazard
*****




Posts: 1247
Registered: 23-11-2017
Location: Rome-Italy
Member Is Offline

Mood: I'm a maddo scientisto!!!

[*] posted on 2-8-2019 at 11:03


Np-237 has a half life of 2 million years, seems a lot but in reality is not really a huge amount of time.
quote from wikipedia: Americium-241 decays to 237Np emitting alpha particles of 5 different energies, mostly at 5.486 MeV (85.2%) and 5.443 MeV (12.8%). Because many of the resulting states are metastable, they also emit gamma rays with the discrete energies between 26.3 and 158.5 keV.





---------------------------------------------------------------------
feel free to correct my grammar, or any mistakes i make
---------------------------------------------------------------------
View user's profile View All Posts By User
vmelkon
National Hazard
****




Posts: 669
Registered: 25-11-2011
Location: Canada
Member Is Offline

Mood: autoerotic asphyxiation

[*] posted on 2-8-2019 at 12:30


It would mean that Np237 turns into Pa233 which beta- decays to U233.
Is my geiger counter really detecting that much beta- particles? I have doubts.

Or perhaps it is detecting gamma radiation of weak energy, of different energy levels?




Signature ==== Is this my youtube page? https://www.youtube.com/watch?v=tA5PYtul5aU
We must attach the electrodes of knowledge to the nipples of ignorance and give a few good jolts.
Yes my evolutionary friends. We are all homos here.
View user's profile View All Posts By User
Ubya
International Hazard
*****




Posts: 1247
Registered: 23-11-2017
Location: Rome-Italy
Member Is Offline

Mood: I'm a maddo scientisto!!!

[*] posted on 2-8-2019 at 16:31


Quote: Originally posted by vmelkon  
It would mean that Np237 turns into Pa233 which beta- decays to U233.
Is my geiger counter really detecting that much beta- particles? I have doubts.

Or perhaps it is detecting gamma radiation of weak energy, of different energy levels?

as i already said, americium 241 itself emits gamma rays while decaying, alpha decay is not the only way.





---------------------------------------------------------------------
feel free to correct my grammar, or any mistakes i make
---------------------------------------------------------------------
View user's profile View All Posts By User
Spock
Harmless
*




Posts: 22
Registered: 27-3-2014
Member Is Offline

Mood: Slightly Radioactive

[*] posted on 2-8-2019 at 17:15


241Am emits low energy gamma radiation and x-rays in addition to alpha particles. I'd imagine the metal shield of your probe is just attenuating the 60kev gammas. It was designed for much higher energy photons.
View user's profile View All Posts By User
vmelkon
National Hazard
****




Posts: 669
Registered: 25-11-2011
Location: Canada
Member Is Offline

Mood: autoerotic asphyxiation

[*] posted on 2-8-2019 at 17:52


Thanks guys. That explains it.



Signature ==== Is this my youtube page? https://www.youtube.com/watch?v=tA5PYtul5aU
We must attach the electrodes of knowledge to the nipples of ignorance and give a few good jolts.
Yes my evolutionary friends. We are all homos here.
View user's profile View All Posts By User

  Go To Top