Handmade Air Geiger Counter

Natural radiation

Let's measure radiation. A sample that acquisition is easy and safe is low-salt used for the dietary therapy for high blood pressures.
Weight distribution: Sodium chloride 50%(NaCl) and potassium chloride 50%(KCl). You can get it in a supermarket.
0.0117% of the potassium in a nature is 40K of radioisotope. 40K emits a beta ray.
Calculating from an atomic weight, 3mg per 100g of this low-salt 40K is included.
The salt (NaCl 99%) which does not contain potassium chloride for comparison is also prepared.

Preparation
  1. Put the gas of a lighter into an air Geiger Mueller counter. Butane gas is heavier than air.(Air:Butone=1.00:2.08). It takes 10 seconds. Butane gas is flammable gas. Be careful not to ignite.
  2. Measure a background. A relative dose of radiation is measured on the basis of this.
  3. Wrap a sample to use easily. A beta ray passes a wrap.

Tips on measurement Measurement result
SampleFirst[cpm]Second[cpm]Average[cpm]
Background11910
Low salt(NaCl+KCl)252123
Salt(NaCl)91311
glow tube starter(Fluorescent Starter)211121732142

Consideration All the food containing potassium emits radiation.
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