Differential spectra of the internal bremsstrahlung from the first-forbidden beta decay of 143Pr and 204Tl

Studies on inner bremsstrahlung from a few beta-emitting isotopes

“…The experimental investigations on the IB emission from forbidden β transitions have shown marked deviations from theoretical predictions (Narasimhamurthy and Jnanananda 1967, Hakeem and Goodrich 1962, Persson 1965, 1964, Kreische et al 1968, Beatie and Byrne 1971, Narayana et al 1977, Prasad Babu et al 1976, Ricci 1958, Berenyi et al 1969. Common to all these studies is the fact that the later half of the IB intensity spectrum deviated positively from the theories.…”

Internal bremsstrahlung from Pr-143

“…The second measurement of Starfelt and Cederlund indicated that the measured bremsstrahlung yield exceeds considerably the KUB theory as well as modified KUB theory due to Nilsson (Coulomb corrected theory -KUBN) [5]. On the other hand, the differential measurements of Berenyi et al [16] showed a close correspondance between the (Coulomb corrected theory-KUBN) [5]. On the other throughout the energy region studied from 50 to 550 keV.…”

“…Even then the observed discrepancy between theory and experiment could not be totally eliminated. Recently, attempts are being made to explain the observed experimental excess over theory in the case of IB from the forbidden beta decaying isotopes in terms of the so called detour transitions [10][11][12][13][14][15][16] which are expected to be significant in the case of forbidden beta decaying isotopes. In the case of 143pr, there have been only two single counter measurements [17,18] and one differential measurement [-16] available in the literature so far.…”