Gamow Teller Beta Decay in Drip Line Nuclei
(1997) Abstract
 Before radioactive ion beams became available, the GamowTeller (GT) giant resonance was studied using chargeexchange reactions such as (p,n) and (He,t). In betastable nuclei, which can be used as targets, the GT giant resonance lies above the ground state of the mother nucleus. In this thesis the GT strength distribution is studied for deformed proton drip line nuclei with 28 < Z < 72. For these nuclei a large part of the GT strength can be reached through beta decay and one does not have the problem of subtracting the background, which is always present in chargeexchange reactions. Protonrich nuclei play an important role in the rapidproton capture process (rpprocess). To understand the rpprocess one would like to know... (More)
 Before radioactive ion beams became available, the GamowTeller (GT) giant resonance was studied using chargeexchange reactions such as (p,n) and (He,t). In betastable nuclei, which can be used as targets, the GT giant resonance lies above the ground state of the mother nucleus. In this thesis the GT strength distribution is studied for deformed proton drip line nuclei with 28 < Z < 72. For these nuclei a large part of the GT strength can be reached through beta decay and one does not have the problem of subtracting the background, which is always present in chargeexchange reactions. Protonrich nuclei play an important role in the rapidproton capture process (rpprocess). To understand the rpprocess one would like to know several decay and capture rates, e.g. beta decay rates and proton capture rates, of protonrich nuclei and nuclei at the proton drip line.
The distribution of the GT beta strength is estimated for the oblate and the prolate HartreeFock (HF) local minima of eveneven nuclei, using the quasiparticle TammDancoff approximation (TDA) based on a deformed HF+BCS calculation with Skyrme interaction. The Skyrme interactions SIII and SG2 are used in the HF ground state calculation. The eigenstates are expanded in a harmonic oscillator basis. Pairing correlation is treated in the BCS approximation with a given pairing gap parameter (1 MeV).
In the region of 28 < Z < 44 the distribution often depends sensitively on the nuclear shape (namely, oblate or prolate). In this region the possibility of observing betadelayed proton emission depends sensitively on the excess of Z over Z=N. The prolate local minima and the oblate local minima lie energetically close for these nuclei. In the region of 54 < Z < 72 almost all the GT strength lies below the ground state of the mother nuclei. The GT strength distribution is not sensitive to deformation. For the isotones N=74 and N=76 close to the proton drip line, the total GT strength is always larger for the prolate shape compared to the oblate shape. Approaching the proton drip line the total GT strength increases. The observation of the total GT strength by betadelayed chargedparticle(s) emission will be of essential importance. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/28969
 author
 Frisk, Fredrik ^{LU}
 opponent

 Dr Liotta, Roberto, Physics at Frescati, KTH, 104 05 Stockholm
 organization
 publishing date
 1997
 type
 Thesis
 publication status
 published
 subject
 keywords
 gravitation, relativity, proton drip line, GamowTeller giant resonance, beta decay, HartreeFock calculation, prolate, oblate, deformed nuclei, TammDancoff approximation, Mathematical and general theoretical physics, quantum mechanics, classical mechanics, statistical physics, thermodynamics, Matematisk och allmän teoretisk fysik, klassisk mekanik, kvantmekanik, relativitet, statistisk fysik, termodynamik, Fysicumarkivet A:1997:Frisk
 pages
 62 pages
 defense location
 Föreläsningssal B på fysiska institutionen
 defense date
 19970221 10:30
 external identifiers

 Other:ISRN: LUNDMPh97/01
 ISBN
 9162823329
 language
 English
 LU publication?
 yes
 id
 6ef827653ac04c2c8b3f1213d61c9d84 (old id 28969)
 date added to LUP
 20070614 09:58:46
 date last changed
 20160919 08:45:18
@phdthesis{6ef827653ac04c2c8b3f1213d61c9d84, abstract = {Before radioactive ion beams became available, the GamowTeller (GT) giant resonance was studied using chargeexchange reactions such as (p,n) and (He,t). In betastable nuclei, which can be used as targets, the GT giant resonance lies above the ground state of the mother nucleus. In this thesis the GT strength distribution is studied for deformed proton drip line nuclei with 28 < Z < 72. For these nuclei a large part of the GT strength can be reached through beta decay and one does not have the problem of subtracting the background, which is always present in chargeexchange reactions. Protonrich nuclei play an important role in the rapidproton capture process (rpprocess). To understand the rpprocess one would like to know several decay and capture rates, e.g. beta decay rates and proton capture rates, of protonrich nuclei and nuclei at the proton drip line.<br/><br> <br/><br> The distribution of the GT beta strength is estimated for the oblate and the prolate HartreeFock (HF) local minima of eveneven nuclei, using the quasiparticle TammDancoff approximation (TDA) based on a deformed HF+BCS calculation with Skyrme interaction. The Skyrme interactions SIII and SG2 are used in the HF ground state calculation. The eigenstates are expanded in a harmonic oscillator basis. Pairing correlation is treated in the BCS approximation with a given pairing gap parameter (1 MeV).<br/><br> <br/><br> In the region of 28 < Z < 44 the distribution often depends sensitively on the nuclear shape (namely, oblate or prolate). In this region the possibility of observing betadelayed proton emission depends sensitively on the excess of Z over Z=N. The prolate local minima and the oblate local minima lie energetically close for these nuclei. In the region of 54 < Z < 72 almost all the GT strength lies below the ground state of the mother nuclei. The GT strength distribution is not sensitive to deformation. For the isotones N=74 and N=76 close to the proton drip line, the total GT strength is always larger for the prolate shape compared to the oblate shape. Approaching the proton drip line the total GT strength increases. The observation of the total GT strength by betadelayed chargedparticle(s) emission will be of essential importance.}, author = {Frisk, Fredrik}, isbn = {9162823329}, keyword = {gravitation,relativity,proton drip line,GamowTeller giant resonance,beta decay,HartreeFock calculation,prolate,oblate,deformed nuclei,TammDancoff approximation,Mathematical and general theoretical physics,quantum mechanics,classical mechanics,statistical physics,thermodynamics,Matematisk och allmän teoretisk fysik,klassisk mekanik,kvantmekanik,relativitet,statistisk fysik,termodynamik,Fysicumarkivet A:1997:Frisk}, language = {eng}, pages = {62}, school = {Lund University}, title = {Gamow Teller Beta Decay in Drip Line Nuclei}, year = {1997}, }