1,721,008 research outputs found
Feasibility of Nuclear Plasma Interaction studies with the Activation Technique
No full text>Magister Scientiae - MScElectron-mediated nuclear plasma interactions (NPIs), such as Nuclear Excitation
by Electron Capture (NEEC) or Transition (NEET), can have a signi cant impact
on nuclear cross sections in High Energy Density Plasmas (HEDPs). HEDP
environments are found in nuclear weapons tests, National Ignition Facility (NIF)
shots and in the cosmos where nucleosynthesis takes place. This thesis explores
the impact of NPIs on highly excited nuclei. This impact is understood to be more
intense in highly-excited nuclei states in the quasi-contiuum which is populated
by nuclear reactions prior to their decay by spontaneous
-ray emission. Attempts
thus far have failed in measuring the NEEC process [1, 2], while NEET process
has been observed experimentally [3, 4]. Direct observation of NPIs is hindered
by the lack of a clear signature of their effect in HEDP environments. Hence this
should test a new signature [5] for NPIs for highly-excited nuclei by investigating
isomeric to ground state feeding from the isomeric state. An experiment was performed
using the reactions 197Au(13C, 12C)198Au and 197Au(13C, 12C2n)196Au at
Lawrence Berkeley National Laboratory in inverse kinematics with an 197Au beam
of 8.5 MeV/u energy. Several measurements were performed with different target
configurations. The activated foils were counted at the low-background counting
facility of Lawrence Livermore National Laboratory. From these data, the double
isomeric to ground state ratio (DIGS) were extracted with the assistance of the
decay equations that were included in the experiment. As the NPIs effects are
rather small the lines for analysis had to be chosen carefully so that the extracted
ratios would not contain significant errors. The measured DIGS ratios were then
compared with the result of the theoretical DIGS ratios. The results showed that
the calculated DIGS ratios deviated substantially from unity although this was
with large uncertainties. Because of the large errors obtained, the DIGS ratios
were found to be inconclusive as a signature for detecting the effects of NPIs such
as angular momentum distribution changes in HEDP environme
Feasibility of Nuclear Plasma Interaction studies with the Activation Technique
No full text>Magister Scientiae - MScElectron-mediated nuclear plasma interactions (NPIs), such as Nuclear Excitation
by Electron Capture (NEEC) or Transition (NEET), can have a signi cant impact
on nuclear cross sections in High Energy Density Plasmas (HEDPs). HEDP
environments are found in nuclear weapons tests, National Ignition Facility (NIF)
shots and in the cosmos where nucleosynthesis takes place. This thesis explores
the impact of NPIs on highly excited nuclei. This impact is understood to be more
intense in highly-excited nuclei states in the quasi-contiuum which is populated
by nuclear reactions prior to their decay by spontaneous
-ray emission. Attempts
thus far have failed in measuring the NEEC process [1, 2], while NEET process
has been observed experimentally [3, 4]. Direct observation of NPIs is hindered
by the lack of a clear signature of their effect in HEDP environments. Hence this
should test a new signature [5] for NPIs for highly-excited nuclei by investigating
isomeric to ground state feeding from the isomeric state. An experiment was performed
using the reactions 197Au(13C, 12C)198Au and 197Au(13C, 12C2n)196Au at
Lawrence Berkeley National Laboratory in inverse kinematics with an 197Au beam
of 8.5 MeV/u energy. Several measurements were performed with different target
configurations. The activated foils were counted at the low-background counting
facility of Lawrence Livermore National Laboratory. From these data, the double
isomeric to ground state ratio (DIGS) were extracted with the assistance of the
decay equations that were included in the experiment. As the NPIs effects are
rather small the lines for analysis had to be chosen carefully so that the extracted
ratios would not contain significant errors. The measured DIGS ratios were then
compared with the result of the theoretical DIGS ratios. The results showed that
the calculated DIGS ratios deviated substantially from unity although this was
with large uncertainties. Because of the large errors obtained, the DIGS ratios
were found to be inconclusive as a signature for detecting the effects of NPIs such
as angular momentum distribution changes in HEDP environme
Investigating the Gamma-ray Strength Function in 74Ge using the Ratio Method
Get PDF>Magister Scientiae - MScAn increasing number of measurements reveal the presence of a low-energy enhancement
in the gamma-ray strength function (GSF). The GSF, which is the
ability of nuclei to absorb or emit
rays, provides insight into the statistical properties
of atomic nuclei. For this project the GSF was studied for 74Ge which was
populated in the reaction 74Ge(p,p')74Ge* at a beam energy of 18 MeV. The data
were collected with the STARS-LIBERACE array at Lawrence Berkeley National
Laboratory. Silicon detector telescopes were used for particle identi cation and
rays in coincidence were detected with 5 clover-type high-purity germanium detectors.
Through the analysis particle-
-
coincidence events were constructed.
These events, together with well-known energy levels, were used to identify primary
rays from the quasicontinuum. Primary
rays from a broad excitation
energy region, which decay to six 2+ states could be identi ed. These states and
the associated primary
rays are used to measure the GSF for 74Ge with the
Ratio Method [1], which entails taking ratios of e ciency-corrected primary
-ray
intensities from the quasicontinuum. Results from the analysis of the data and
focus on the existence of the low-energy enhancement in 74Ge will be discussed.
The results are further discussed in the context of other work done on 74Ge using
the (
,
') [2], (3He,3He') [3] and ( , ') [4] reactions
Feasibility of Nuclear Plasma Interaction studies with the Activation Technique
No full textMagister Scientiae - MSc (Physics)Electron-mediated nuclear plasma interactions (NPIs), such as Nuclear Excitation
by Electron Capture (NEEC) or Transition (NEET), can have a signi cant impact
on nuclear cross sections in High Energy Density Plasmas (HEDPs). HEDP
environments are found in nuclear weapons tests, National Ignition Facility (NIF)
shots and in the cosmos where nucleosynthesis takes place. This thesis explores
the impact of NPIs on highly excited nuclei. This impact is understood to be more
intense in highly-excited nuclei states in the quasi-contiuum which is populated
by nuclear reactions prior to their decay by spontaneous
-ray emission
Investigating the Gamma-ray Strength Function in 74Ge using the Ratio Method
No full text>Magister Scientiae - MScAn increasing number of measurements reveal the presence of a low-energy enhancement
in the gamma-ray strength function (GSF). The GSF, which is the
ability of nuclei to absorb or emit
rays, provides insight into the statistical properties
of atomic nuclei. For this project the GSF was studied for 74Ge which was
populated in the reaction 74Ge(p,p')74Ge* at a beam energy of 18 MeV. The data
were collected with the STARS-LIBERACE array at Lawrence Berkeley National
Laboratory. Silicon detector telescopes were used for particle identi cation and
rays in coincidence were detected with 5 clover-type high-purity germanium detectors.
Through the analysis particle-
-
coincidence events were constructed.
These events, together with well-known energy levels, were used to identify primary
rays from the quasicontinuum. Primary
rays from a broad excitation
energy region, which decay to six 2+ states could be identi ed. These states and
the associated primary
rays are used to measure the GSF for 74Ge with the
Ratio Method [1], which entails taking ratios of e ciency-corrected primary
-ray
intensities from the quasicontinuum. Results from the analysis of the data and
focus on the existence of the low-energy enhancement in 74Ge will be discussed.
The results are further discussed in the context of other work done on 74Ge using
the (
,
') [2], (3He,3He') [3] and ( , ') [4] reactions
Feasibility of Nuclear Plasma Interaction studies with the Activation Technique
Get PDFMagister Scientiae - MSc (Physics)Electron-mediated nuclear plasma interactions (NPIs), such as Nuclear Excitation
by Electron Capture (NEEC) or Transition (NEET), can have a signi cant impact
on nuclear cross sections in High Energy Density Plasmas (HEDPs). HEDP
environments are found in nuclear weapons tests, National Ignition Facility (NIF)
shots and in the cosmos where nucleosynthesis takes place. This thesis explores
the impact of NPIs on highly excited nuclei. This impact is understood to be more
intense in highly-excited nuclei states in the quasi-contiuum which is populated
by nuclear reactions prior to their decay by spontaneous
-ray emission
Feasibility of nuclear plasma interaction studies with the activation technique
No full text>Magister Scientiae - MScElectron-mediated nuclear plasma interactions (NPIs), such as Nuclear Excitation
by Electron Capture (NEEC) or Transition (NEET), can have a signi cant impact
on nuclear cross sections in High Energy Density Plasmas (HEDPs). HEDP
environments are found in nuclear weapons tests, National Ignition Facility (NIF)
shots and in the cosmos where nucleosynthesis takes place. This thesis explores
the impact of NPIs on highly excited nuclei. This impact is understood to be more
intense in highly-excited nuclei states in the quasi-contiuum which is populated
by nuclear reactions prior to their decay by spontaneous
-ray emission. Attempts
thus far have failed in measuring the NEEC process, while NEET process
has been observed experimentally. Direct observation of NPIs is hindered
by the lack of a clear signature of their e ect in HEDP environments. Hence this
should test a new signature for NPIs for highly-excited nuclei by investigating
isomeric to ground state feeding from the isomeric state. An experiment was performed
using the reactions 197Au(13C, 12C)198Au and 197Au(13C, 12C2n)196Au at
Lawrence Berkeley National Laboratory in inverse kinematics with an 197Au beam
of 8.5 MeV/u energy. Several measurements were performed with di erent target
con gurations. The activated foils were counted at the low-background counting
facility of Lawrence Livermore National Laboratory. From these data, the double
isomeric to ground state ratio (DIGS) were extracted with the assistance of the
decay equations that were included in the experiment. As the NPIs e ects are
rather small the lines for analysis had to be chosen carefully so that the extracted
ratios would not contain signi cant errors. The measured DIGS ratios were then
compared with the result of the theoretical DIGS ratios. The results showed that
the calculated DIGS ratios deviated substantially from unity although this was
with large uncertainties. Because of the large errors obtained, the DIGS ratios
were found to be inconclusive as a signature for detecting the e ects of NPIs such
as angular momentum distribution changes in HEDP environments
Investigating the Gamma-ray Strength Function in 74Ge using the Ratio Method
No full text>Magister Scientiae - MScAn increasing number of measurements reveal the presence of a low-energy enhancement
in the gamma-ray strength function (GSF). The GSF, which is the
ability of nuclei to absorb or emit
rays, provides insight into the statistical properties
of atomic nuclei. For this project the GSF was studied for 74Ge which was
populated in the reaction 74Ge(p,p')74Ge* at a beam energy of 18 MeV. The data
were collected with the STARS-LIBERACE array at Lawrence Berkeley National
Laboratory. Silicon detector telescopes were used for particle identi cation and
rays in coincidence were detected with 5 clover-type high-purity germanium detectors.
Through the analysis particle-
-
coincidence events were constructed.
These events, together with well-known energy levels, were used to identify primary
rays from the quasicontinuum. Primary
rays from a broad excitation
energy region, which decay to six 2+ states could be identi ed. These states and
the associated primary
rays are used to measure the GSF for 74Ge with the
Ratio Method [1], which entails taking ratios of e ciency-corrected primary
-ray
intensities from the quasicontinuum. Results from the analysis of the data and
focus on the existence of the low-energy enhancement in 74Ge will be discussed.
The results are further discussed in the context of other work done on 74Ge using
the (
,
') [2], (3He,3He') [3] and ( , ') [4] reactions
Investigating the Gamma-ray Strength Function in 74Ge using the Ratio Method
No full text>Magister Scientiae - MScAn increasing number of measurements reveal the presence of a low-energy enhancement
in the gamma-ray strength function (GSF). The GSF, which is the
ability of nuclei to absorb or emit
rays, provides insight into the statistical properties
of atomic nuclei. For this project the GSF was studied for 74Ge which was
populated in the reaction 74Ge(p,p')74Ge* at a beam energy of 18 MeV. The data
were collected with the STARS-LIBERACE array at Lawrence Berkeley National
Laboratory. Silicon detector telescopes were used for particle identi cation and
rays in coincidence were detected with 5 clover-type high-purity germanium detectors.
Through the analysis particle-
-
coincidence events were constructed.
These events, together with well-known energy levels, were used to identify primary
rays from the quasicontinuum. Primary
rays from a broad excitation
energy region, which decay to six 2+ states could be identi ed. These states and
the associated primary
rays are used to measure the GSF for 74Ge with the
Ratio Method [1], which entails taking ratios of e ciency-corrected primary
-ray
intensities from the quasicontinuum. Results from the analysis of the data and
focus on the existence of the low-energy enhancement in 74Ge will be discussed.
The results are further discussed in the context of other work done on 74Ge using
the (
,
') [2], (3He,3He') [3] and ( , ') [4] reactions
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