摘要:

The effects of isospin-symmetry breaking on proton emission following &bgr;-decay to the isobaric analog state are discussed in detail. Of particular importance is the mixing with a dense background of lower isospin states, whose properties are not well known. The possibility of observingT=4states in even-even,N=Znuclei, which is viable if the decay proceeds via isospin-forbidden particle emission, is also discussed. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1306022

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Well deformed and superdeformed rotational structures in the second well of nuclei near doubly-magic56Niwere recently identified by means of heavy-ion fusion-evaporation reactions. Some of these bands were found to decay by prompt particle emission in competition to the expected decay via &ggr; radiation. Subsequently, dedicated experiments were performed to investigate this exotic decay mode in more detail. First results from these studies are reported. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1306023

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Great progress has been made in the last 20 years in the study of proton emission from unstable nuclei, but the prospects for additional strides in the next several years are bright. The present main limitations on the study of proton radioactivity are related to the inability to produce copious quantities of nuclides beyond the proton drip line, and the difficulty of measuring proton radioactivity of a mass-separated nucleus in the first few microseconds of its existence. At the Holifield Facility we will attack the second of these limitations by using new signal processing CAMAC modules DGF-4C. Digitizing of the preamplifier signals should enable the analysis of a proton decay occurring at times even less than 1 microsecond after an implant in a strip detector. In the same process, the threshold energy at which we can make measurements will be lowered. These two things will hopefully enable the measurement of lower-energy, but faster decays of isotopes in the100Snregion and below. For the latter region, the proton decays crucial for a rp-process scenario are of particular interest (e.g.69Brdecay). Secondly, for very short-lived species, we plan to make measurements (without residue separation) at points much closer to the target, thus reducing the flight time between the target and detector. As more intense radioactive beams become available, eg.56Ni,we will utilize these to produce more neutron-deficient nuclides by use of colder reactions than is possible with stable beams. In some cases where delayed proton emitters are present in the same isobaric chain, the use of the cold reactions with radioactive beams can provide purer samples of the isotope of interest, with a reduction in background from the delayed proton emitters in the same mass chain. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1306024

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

We present the core architecture of XIA’s digital pulse processors and show how digital filtering and pile up inspection are performed in real time. XIA’s pulse processors can simultaneously extract energy and pulse shape information from the detector pulses provided to its inputs. Two applications of this novel technology are discussed in the paper. High resolution for &ggr;-rays was achieved at very short peaking times with digital ballistic deficit correction. Sequences of pulses characteristic of radioactive decay via proton emission can be recognized online with the real-time pileup inspector operated in the reversed logic mode. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1306025

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

Statistical model of &bgr;-delayed proton emission is briefly reviewed. Theory of angular distribution of &bgr;-delayed proton emission from nuclear states oriented at low temperatures is discussed and the design of the first trial experiment using118Csoriented at low temperature at the ISOLDE/NICOLE facility at CERN is described. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1306026

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

The doubly magic nucleus48Nihas been observed for the first time at GANIL. The experiment was performed using a high intensity58Nibeam at 74.5MeV/Aon a nickel target. ThisTZ=−4nucleus is the most proton-rich nucleus ever observed, and is a good candidate for two-proton radioactivity. In this experiment, we also implanted around28042Cr,5043Feand10049Niisotopes, for which no experimental information about the decay is available. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1306027

出版商:AIP    

年代:1900

数据来源: AIP

摘要:

The perspectives for the production of ground-state proton emitters via projectile-fragmentation reactions using beams from the heavy-ion synchrotron SIS at GSI are reviewed. Special focus is placed on the rare-earth isotopes and nuclei in the trans-lead region. In addition, estimates for cross sections and production rates will be given. ©2000 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1306028

出版商:AIP    

年代:1900

数据来源: AIP