[time-nuts] Variation in Radioactive Decay Rate with Solar Activity
brooke at pacific.net
Wed Aug 3 21:20:20 UTC 2011
The problem I'm having is that just counting the clicks from a source is
a way to get random numbers. If you average the clicks over a large
amount of time and plot that average, it will decrease over time. So to
see the change in decay rate the source needs to have a short half-life.
The article mentions (ordered by half life):
manganese-54 (312.03 days or 26.9E6 sec)
cesium-137 (30.17 years)
silicon-32 (170 years or 5.4E9 sec)
radium-226 (1601 years)
manganese-54 looks like the shortest half life that was mentioned and
it's avaialble from United Nucular:
Here's their table of Disk Sources which has some isotopes that have a
shorter half life:
*Cobalt^57 *270 days
*Zinc^65 *244 days
*Polonium^210 * 138 days (also available as a needle source)
So in the disk sources Polonium-210 has the shortest half life.
ISOTOPE ACTIVITY HALF-LIFE ENERGIES (KeV)
*Barium^133 * 1uCi 10.7 years *Gamma: *81.0, 356.0
*Cadmium^109 * 1uCi 453 days *Gamma: *88.0
*Cesium^137 * *1*uCi 30.1 years *Gamma: *32, 661.6
*Beta: *511.6, 1173.2
*Cesium^137 * *5*uCi 30.1 years *Gamma: *32, 661.6
*Beta: * 511.6, 1173.2
*Cesium^137 * *10*uCi 30.1 years *Gamma: *32, 661.6
*Beta:* 511.6, 1173.2
*Cobalt^57 * 1uCi 270 days *Gamma: *122.1
*Cobalt^60 * 1uCi 5.27 years *Gamma: *1173.2, 1332.5
*Europium^152 * 1uCi 13.5 years *Gamma: *121.8, 344.3, 1408.0
*Manganese^54 * 1uCi 312 days *Gamma: *834.8
*Sodium^22 * 1uCi 2.6 years *Gamma: *511.0, 1274.5
*Strontium^90 * 0.1uCi 28.5 years *Beta: *546.0
*Thallium^204 * 1uCi 3.78 years *Beta: *763.4
* Polonium^210 * 0.1uCi 138 days *Alpha: *5304.5
*Zinc^65 * 1uCi 244 days *Gamma: *511.0, 1115.5
Jim Lux wrote:
> On 8/3/11 12:14 PM, J. Forster wrote:
>> Hi Brooke,
>> Maybe. The photon counting gear is pretty trivial. You'd need:
>> A scintillator
>> A PMT (Photo Multiplier Tube) and HV stable HV PS.
>> A preamp
>> A SCA (Single Channel Analyzer). These can be built.
>> A counter, stable time base, and data recorder
>> The main difficulty, IMO, would be getting a sufficient sized lump of
>> material. Chunks of Cs don't grow on trees, at least not where I live.
> Does it have to be Cs? United Nuclear sells a wide variety of
> calibration sources for <$100. Yes, they have Cs137 (10 microCuries)...
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