Realisation of a β spectrometer solenoidal and a double β spectrometer at coincidence

The two spectrometers have been achieved to tackle numerous problems of nuclear spectrometry. They possess different fields of application that complete themselves. The solenoidal spectrometer permits the determination of the energy limits of β spectra and of their shape; it also permits the determination of the coefficients of internal conversion and reports αK / αL and it is especially efficient for the accurate energy levels of the γ rays by photoelectric effect. The double coincidence spectrometer has been conceived to get a good efficiency in coincidence: indeed, the sum of the solid angles used for the β and γ emission is rather little lower to 4π steradians. To get this efficiency, one should have sacrificed a little the resolution that is lower to the one obtained with the solenoidal spectrometer for a same brightness. Each of the elements of the double spectrometer can also be adapted to the study of angular correlations βγ and e-γ. In this use, it is superior to the thin magnetic lens used up to here. The double spectrometer also permits the survey of the coincidences e-e-, e-β of a equivalent way to a double lens; it can also be consider some adaptation for the survey of the angular correlations e-e-, e-β. Finally, we applied the methods by simple spectrometry and by coincidence spectrometry, to the study of the radiances of the following radioelements: 76As (26 h), 122Sb (2,8 j), 124Sb (60 j), 125Sb (2,7 years). (M.B.)