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truthrevealer
New Zealand
2 Posts |
 Posted - 06/20/2014 : 01:02:05
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Testing my new counter for consistency.Used 5min counting
Orientation:
upright on table 19.0cpm /inverted 16.2cpm
Repeated this and confirmed that cpm depends upon orientation.
Temperature of Object:2L milk container
empty 18 celcius 18.8cpm
water 15 celcius 16.5cpm
milk 11 cecius 15.6cpm
cpm lowers with temp
The reason I did this was that I wanted to test the milk;I then realised that the temperature was affecting the results.
As in any experiment,there are only 2 variables.Everything else should be constant.So with this counter,consistency is required,otherwise invalid conclusions may be drawn.
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Alchemy2
Canada
89 Posts |
Posted - 06/22/2014 : 02:23:17
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How did you do this experiment? First off, unless the unit was immersed in the fluid, even in a bag, the temp reading is really only valid for the unit's temp, not the fluid under check, because the temp measured internally using some form of resistive temperature device.
Also, the orientation may change the CPM if the tube is further from the object under test. Did you try taking background measurements around your environment and flip the unit? does this result still show? |
The more I learn, the more I realize I do not know! |
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| Reply #2
Alchemy2
Canada
89 Posts |
Posted - 06/22/2014 : 02:28:15
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The reason I ask these questions is unless you understand HOW these units work, any results you get are subject to invalid conclusions. For example: Under natural background determinations, I get the same CPM regardless of orientation using my 320+. Secondly, ANY CPM measurements need to have the background subtracted to yield counts due to the object being investigated. Thirdly, the distance of the tube from the radioactive source, esp. a very weak one, will have a HUGE affect on the counts.
I would not worry about the temperature values, because I believe this is more of an indicator to ensure that the unit itself (internal temp) is within the recommended specs for normal operation of the unit. |
The more I learn, the more I realize I do not know! |
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| Reply #3
Alchemy2
Canada
89 Posts |
Posted - 06/22/2014 : 03:38:21
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| Try resetting your unit and repeat this experiment. It would be interesting to see the results. There may be a temperature to sensitivity or response effect, but one needs to ensure that the temp of the unit is stable and in equilibrium with the sample to ensure the observations are fully valid enough to correlate any conculsion sbased on the data. |
The more I learn, the more I realize I do not know! |
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320+ background-orientation/temperature
