Direct Observation of Two Proton Radioactivity Using Digital Photography

Journal Article · Mon Jan 01 00:00:00 EST 2007 · Nature

OSTI ID:931406

Rykaczewski, Krzysztof Piotr ^[1]; Pfutzner, M ^[2]; Dominik, Wojciech ^[3]; Janas, Z ^[2]; Miernik, K ^[4]; Bingham, C R ^[5]; Czyrkowski, Henryk ^[3]; Cwiok, Mikolaj ^[3]; Darby, Iain ^[5]; Dabrowski, Ryszard ^[3]; Ginter, T N ^[6]; Grzywacz, Robert Kazimierz ^[1]; Karny, M ^[2]; Korgul, A ^[2]; Kusmierz, Waldemar ^[3]; Liddick, Sean ^[5]; Rajabali, Mustafa ^[5]; Stolz, A ^[6]

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1. ORNL
2. IEP, Warsaw University
3. Warsaw University
4. IEP, University of Warsaw
5. University of Tennessee, Knoxville (UTK)
6. NSCL Michigan State University

Recently the observation of a new type of spontaneous radioactive decay has been claimed in which two protons are simultaneously ejected by an atomic nucleus from the ground state1,2,3. Experimental data obtained for the extremely neutron-deficient nuclei 45Fe and 54Zn, were interpreted as the first evidence of such a decay mode which has been sought since 1960.4 However, the technique applied in those studies allowed only measurements of the decay time and the total energy released. Particles emitted in the decay were not identified and the conclusions had to be supported by theoretical arguments. Here we show for the first time, directly and unambiguously, that 45Fe indeed disintegrates by two-proton decay. Furthermore, we demonstrate that the decay branch of this isotope leads to various particle emission channels including two-proton and three-proton emission. To achieve this result we have developed a new type of detector V the Optical Time Projection Chamber (OTPC) in which digital photography is applied to nuclear physics for the first time. The detector records images of tracks from charged particles, allowing for their unambiguous identification and the reconstruction of decay events in three dimensions. This new and simple technique provides a powerful method to identify exotic decay channels involving emission of charged particles. It is expected that further studies with the OTPC device will yield important information on nuclei located at and beyond the proton drip-line, thus providing new material for testing and improving models of very unstable atomic nuclei.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Holifield Radioactive Ion Beam Facility (HRIBF)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 931406
• Journal Information: Nature, Journal Name: Nature
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CHARGED PARTICLES
DECAY
DIMENSIONS
NUCLEAR PHYSICS
NUCLEI
PHOTOGRAPHY
PROTONS
RADIOACTIVITY
TESTING
TIME PROJECTION CHAMBERS