# Why you never dismatle an ionization fire alarm !

Discussion in 'General Science & Technology' started by Hideki Matsumoto, Oct 19, 2004.

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1. ### Hideki Matsumotoñ{ìñÇÃóùâ?ÇÕêSÇÃíÜÇ©ÇÁóàÇ ÈÅBRegistered Senior Member

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Unfortunatly I am no good at reading danger signs !! well I will give an example of what happend to me yesterday when I took an ionization firealarm apart and stripped the 1.0uCi of Am241 out of it so I could use it as a test source. apon measureing the ionization source on Gamma detection I ended up with a very small reading of around 145.2CPM which is almost 10x backround. Apon measureing with the beta and gamma setting about 645CPM was observed. Still a radioactive source would not have a danger sign if this was the activity... Well I soon discovered why it was so dangerous. When I set my counter to broad spectrum count a+b+y the count soared to around 18,500 CPM / 185 uSv/hr !!THIS IS REALLY DANGEROUS !!! and like plutonium Am241 is a very heavy alpha emitter. Alpha radiation is the most dangerous! Legally a person needs a licence to posess anything over 5000CPM 50uSv/hr!!

3. ### NasorValued Senior Member

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I'm pretty sure that Alpha particles are the least dangerous. They don't even penetrate human skin.

5. ### catoless hate, more scienceRegistered Senior Member

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what did you do with it when you found that out?

7. ### Hideki Matsumotoñ{ìñÇÃóùâ?ÇÕêSÇÃíÜÇ©ÇÁóàÇ ÈÅBRegistered Senior Member

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I still have the source as a tester. It is now in a alpha sheilded container. Glass works just fine. Alpha particles according to the nuclear regulatory commission are the most dangerous since these are the most ionizing of all the types of ionizing radiation even thought they have the smallest emisson range. If alpha particles are inhaled or taken internally they cause 3x damage to cells than beta or Gamma radiation.

I am planning on selling the source along with an older model geiger counter for a test source. I hope the C.N.R.C. dosen't come a knocking!

I am still in shock as to the measurement of of this 1uCi source!! 18,500 - 20,000 CPM is fucking crazy !

10. ### vslayerRegistered Senior Member

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seems strange that there would be $70 or am241 in a$20 smoke alarm

11. ### geodesic"The truth shall make ye fret"Registered Senior Member

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Alpha emitters are only more dangerous if you actually ingest them, or you go around holding it. The worst radiation in general terms are neutrons, as they are very hard to shield against, but are comparatively very ionizing. High energy protons are also very nasty, but only if you leave the magnetosphere.

12. ### Boris2Valued Senior Member

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http://www.ansto.gov.au/edu/nuclear_age/nuclear_age_biol.htm

Some types of nuclear radiation are more damaging than others. Alpha radiation is the most damaging to human tissues because its particles are 'large' and strongly ionising. Luckily, alpha radiation is easily blocked (eg by skin), but if an alpha-emitting substance enters the body, the results can be serious....

Last edited: Oct 20, 2004
13. ### curioucityUnbelievable and oddRegistered Senior Member

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What a contradiction.... the easiest to block is the most deadly.... but it may make sense anyway...... ionized Helium atoms running rampant......

14. ### Hideki Matsumotoñ{ìñÇÃóùâ?ÇÕêSÇÃíÜÇ©ÇÁóàÇ ÈÅBRegistered Senior Member

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My feeling is that this Am241 source is from an OLD industrial firealarm! Am241 is NOT cheap. I have a hunch that the source I got is 5-10uCi not 1.0 uCi. Again I have two sources. 1 is defently 1.0uCi and is worth about $15.00 -$20.00 and puts out just shy of 76uSv 760CPM on a+b+y setting. This HOT sample I speak of is at least 6x the size and is outputting 365uSv/hr 36,500CPM which way too hot for home use. The nuclear controll agency just about freaked when I told them how hot it was.
Am241 is also highly toxic just as Plutonium is. By the way Am241 is Plutonium 238 bombarded with x-rays, this then transmutates into Am241.

15. ### guthrieparadox generatorRegistered Senior Member

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That reminds me of the lab I used to work in. It had an Americium source that gave off a great deal of neutrons, for the analysis of the amount of Boron in a sample, Boron being the best stuff for stopping neutrons. Once all the world wide terrorist stuff blew up, the management found they had to beef up security, to stop some terrorist walking in and stealing the americium source to make a dirty bomb with. As if. The resulting extra door and couple of locks would have stopped only a five year old child.

Hmmm, a quick google on Americium 241 says it doenst emit neutrons, but thats what the machine said its source was.
However, it does say that:
as a solid under normal conditions. Americium is
produced when plutonium absorbs neutrons in nuclear
reactors and nuclear weapons tests."

from:

16. ### Hideki Matsumotoñ{ìñÇÃóùâ?ÇÕêSÇÃíÜÇ©ÇÁóàÇ ÈÅBRegistered Senior Member

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Duh guthie. That is what I said. TRY READING! Am241 emmits very low gamma radiation and ultra high alpha radiation. do you know what transmutation is ?

17. ### GiftedWorld WandererRegistered Senior Member

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I'd think that even for industrial uses, a smoke detector would not have enough Am241 to be illegal without a license. After all, think about how difficult it is to get a permit like that. I'm sure it's too hard for every company that gets a smoke detector to get a permit just for the smoke detectors.

I'm thinking the alpha rays, while most damaging, would be the least dangerous, because of what you'd have to do to get them where it'll hurt. Like you said, a glass bottle is an acceptable container, it would take carelessness, sheer idiocy, or ignorance to put it where it can cause problems(in a pocket/swallowed).

You said you took it out of the fire alarm. What did it say about how old it was?

18. ### ElectricFetusSanity going, going, goneValued Senior Member

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Alpha is the least penetrating, even though it is also the most damaging radiation per energy, these means that if you did not ingest the Am241 your fine, if you did well

19. ### Hideki Matsumotoñ{ìñÇÃóùâ?ÇÕêSÇÃíÜÇ©ÇÁóàÇ ÈÅBRegistered Senior Member

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Well try telling that to the CNRA/CNRC. The reason you can have an ionization alarm in the house is simply because it has a sheild around the ion chamber source. As soon as the source is exposed it is illegal to posses because it emits over 50uSv/hr. Alpha radiation is as you say not penitrating, I am really not worried about it althought it gave me a scare when the radiation levels climbed to the 376.3uSv/hr mark, I have never seen such an active source other than fuel rods at a nuclear power station in Ontario.
The law however is very restrictive on high level sources. My guess is the active source is from an early 1970's model industrial variety.

20. ### Hideki Matsumotoñ{ìñÇÃóùâ?ÇÕêSÇÃíÜÇ©ÇÁóàÇ ÈÅBRegistered Senior Member

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By the way Am241 does emmit weak gamma rays/nutrons at about 140CPM for this particular sample. Another sample I have that is 1.0uCi emits around 89CPM of Gamma.
Beta emissions are around 300-410CPM

21. ### invert_nexusZe do caixaoValued Senior Member

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Your talk of smoke alarms reminded me of a story that was linked in a thread I read quite a while back. I finally remembered what to search for and found the the link.

22. ### vslayerRegistered Senior Member

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off to the junkyard with me then