High-Energy Gamma Rays from the Proton Bombardment of Fluorine

Abstract

BABULAL SARAFsuggests allowed beta transitions to the 535-and 650kev levels as observed. However, with the invocation of conventional selection rules, it is not possible to explain the large value of log ft of the transition to the 57-minute metastable level (A/=l, no, allowed).Recently, De-Shalit and Goldhaber 15 have discussed the problem of anomalous values of log ft for allowed and first forbidden beta transitions. They have emphasized the possible influence of the nuclear core. Their explanation can be applied if the ground state of Ru 103 is assumed to have orbital g 7 /2. In that event K one or more pairs of neutrons of orbital d 5 / 2 will be present in the ground state configuration of Ru 103 . The most probable configuration would be g 7 /2 7 d 5/2 2 . On the other hand, the effect of the g 9 /2 protons of Rh 103 on the isomeric and 95-kev levels would be such as to make the neutron configuration of those levels g7/2 8 d 5/ 2 0 . According to De-Shalit and Goldhaber, 15 the beta transitions would be further slowed by the change of orbitals (^5/2-^7/2) experienced by one pair of neutrons. From these considerations, it can be said 15 A. De-Shalit and M. Goldhaber, Phys. Rev. 92, 1211 (1953).Resonances for emission of gamma rays of energy greater than 8 Mev in the reaction F 19 (;£,y)Ne 20 have been measured for proton energies from 550 to 1450 kev using a thin target. Resonances were seen at 669, 874, 935, 980, 1090, 1280, 1320, 1355, 1380, and 1430 kev. The effect of false high-energy gamma-ray counts resulting from the nearly simultaneous detection of two 6-7 Mev gamma rays in the reaction F 19 (£,ay)0 16 was noted and a method for correcting for this effect was devised. The intensities of gamma rays for the two reactions were compared at each resonance. Also, the angular distribution of the 12-Mev gamma rays emitted at the 669-kev (p,y) resonance was measured and found to be isotropic to within two percent probable error.

Detectors and Cultural Heritage: The INFN-CHNet Experience

“…Examples of the complementary use of the PIXE and PIGE techniques are quite common; see, for example, [161,162]. However, production cross sections for gamma rays are much smaller than those for X-rays, which makes the sensitivity of PIGE generally worse than that of PIXE [163][164][165][166][167].…”