Proton spectroscopy ofNi48,Fe46, andCr

Abstract

Results of decay spectroscopy on nuclei in vicinity of the doubly magic 48 Ni are presented. The measurements were performed with a Time Projection Chamber with optical readout which records tracks of ions and protons in the gaseous volume. Six decays of 48 Ni, including four events of twoproton ground-state radioactivity were recorded. An advanced reconstruction procedure yielded the 2p decay energy for 48 Ni of Q2p = 1.29(4) MeV. In addition, the energy spectra of β-delayed protons emitted in the decays of 44 Cr and 46 Fe, as well as half-lives and branching ratios were determined. The results were found to be consistent with the previous measurements made with Si detectors. A new proton line in the decay of 44 Cr corresponding to the decay energy of 760 keV is reported. The first evidence for the β2p decay of 46 Fe, based on one clear event, is shown.

Puzzling Two-Proton Decay of Kr67

“…Results.-We first investigate the spherical 2p emitter 48 Ni, which has been the subject of numerous theoretical studies [12,19,21,[51][52][53][54]. By assuming the experimental value of Q 2p = 1.310 MeV we obtain T 1/2 = 14 ms, which agrees reasonably well with experiment, T [14]. Moreover, we found that calculations with different sets of WS parameters result in fairly similar decay widths, which is in accord with the conclusion of Ref.…”

“…was observed for the first time in 45 Fe [9, 10], and, later on, in 19 Mg [11],, and 54 Zn [15,16]. Interest in this exotic phenomenon has been envigorated by measurements of proton-proton correlations in the decay of 45 Fe [17], 19 Mg [18], and 48 Ni [14], which have demonstrated the unique threebody features of the process and -when it comes to theory -the sensitivity of predictions to the angular momentum decomposition of the 2p wave function. The highquality 2p decay data have called for the development of comprehensive theoretical approaches, capable of simultaneous description of structural and reaction aspects of the problem [4,5].…”

Gaseous and dual-phase time projection chambers for imaging rare processes

“…Therefore, and contrary to TPCs at colliders, operation under magnetic field will be seldom found throughout this text. But even in rcases where the event topology is dull and a handful of fairly straight tracks must be detected, the ionization profiles may need to be reconstructed in modern TPCs with a very fine pixelization (mm and sub-mm scale), in order to identify the reaction products [15][16][17], the direction and sense of their momentum vector [11,12] or the polarization of an incoming particle [18,19]. Despite recent progress (e.g.…”

Beyond the proton drip line: Bayesian analysis of proton-emitting nuclei

“…Of particular interest is the phenomenon of ground state two-proton (2p) radioactivity found in a few very proton-rich even-Z isotopes, in which single proton decay is energetically forbidden or suppressed due to proton pairing and the resulting odd-even binding energy effect [8]. Currently, 2p radioactivity has been detected in a handful of nuclei: 19 Mg [9], 45 Fe [10,11], 48 Ni [12][13][14][15], 54 Zn [16,17], and 67 Kr [18]. In addition, several broad resonances associated with 2p decay were reported in, e.g., 6 Be [19] and 11,12 O [20,21].…”