I am measuring radiation from 6 tritium glow keychains. Usual gamma detector does not detect anything (this is expected), but on beta detector with thin window I am getting about 5 counts per second.
Count rate drops by mere 10% when using 1mm plastic shield.
My understanding is that I am not actually detecting betas, but rather weak secondary X-Ray radiation generated when electrons travel through keychain's plastic. Is that correct?
Answer
I would agree with the general conclusions regarding soft x-rays. I have measured the attenuation of x-rays in every day materials at energies below 20 Kev and to a first approximation can be described by :- E½ = K t^1/3.25 where t is the thickness in cm. E½ the energy at which the intensity is reduction to ½ . K is the coefficient of the material. For example a sheet of solid styrene K = 17.77 and E½ = 8.7 Kev for 1 mm thick sample. While the exact K value will depend some what on your particular specimen it might be interesting to compare the attenuation using other materials.
Cling film 13.3, Black card 18.4, Writing paper 23.5, Black polythene 14.7, Clear polythene 13.3, Mica 51, PCB Fibre glass 40, Beryllium 11.23 , Aluminium 46.6,
No comments:
Post a Comment