Hello John,JMZ421 wrote: ↑Tue Mar 29, 2022 10:01 amFor every inch you move that device away from the gauges the CPM's go down substantially. I do not want to sound too stupid but based on your calculation how long would someone have to be seated in front of the gauges(your right knee, specifically) for there to be any danger to your body? I would think that is the basic question to be answered. The concern should be opening up those gauges to repair which has been discussed often. Really appreciate your input as this is very interesting.
Thanks, John
Yes, it's normal to measure less radiations when you move away from the source. Thanks god we are living far away from Tchernobyl or Fukushima.
The Sievert is the unit used to measure the dose that a human body receives with regards to what is exposed to the radiations
The CPM (count rate per minute) is a measure made by detecting the particles.
Sivert is more appropriate to evaluate the effects on human body.
My detector in the video was showing the radiation in real time in µSv/h while at the bottom of the screen there was an accumulation of the dose calculated as long as the detector was active. This can give you the yearly dose in µSv/year
Here are the dose limits :
You would have to spend a year near a source of 0.114 µSv/h to reach the limit for the public or 1 mSv/yr (one milli Sievert per year)
When you reach 10mSv/y you have to ask the public to protect himself for example by staying at home.
When you reach 50mSv/y you have to evacuate the public to non contaminated areas.
Strong doses are considered when speaking about 100 mSv per year. Again it is 100 milli Sievert/year...not 2 micro Siervert/hour like with the speedometer.
In Europe the limit for workers in nuclear power plants is 20 mSv/year. (milli Sievert per year)
That is roughly the limit that you would reach if you decide to put the fuel gauge in your pocket or have your knee in your jeep near the gauges during one full year, 7/24.
Example in my jeep: 2.5 µSv/h (micro Sievert) measured with my dosimeter on my jeep dashboard means an accumulated dose of 22 Millisievert per year [mSv/y] which is just above the limit for workers in the nuclear industry.
As you do not put your fuel gauge in your pocket or you do not work/repair/restore all along the year speedometers with Ra-226, you have not to be worry.
Your integrated dose on a full year is way below the safety limit.
I have measured the Stewart Warner speedometer found in the ground of battlefield of the Bulge that I restored a few years ago and it is completely inert. The radium was "cleaned up" by water during the 65 years spent in the ground.
My other post war CJ-2a KS Speedos, or Studebaker SW speedometers are also completely inert.
Yves