Fine structure in the photoneutron spectra from praseodymium-141 and lead

1970 ◽  
Vol 48 (8) ◽  
pp. 950-953 ◽  
Author(s):  
K. G. McNeill ◽  
J. W. Jury ◽  
J. S. Hewitt
Keyword(s):  
Fine Structure ◽  
Excited State ◽  
Energy Spectrum ◽  
Cross Section ◽  
Ground State ◽  
Giant Dipole Resonance ◽  
Daughter Nucleus ◽  
State Transitions ◽  
Dipole Resonance ◽  
Section Curve

Careful measurements of the energy spectrum of photoneutrons ejected from praseodymium and from natural lead show that there are peaks on top of the expected smooth spectrum. Comparison with the recent cross-section studies, which indicate structure on the giant dipole resonance for these nuclei, shows agreement between the energies of the peaks found in the present work and the energies En = E−Qi where E corresponds to a peak in the cross-section curve and Qi is the threshold for producing a given state in the daughter nucleus. Only ground state transitions (for Pr) or ground state and the first two excited state transitions (for Pb) need be invoked.

Photoneutron cross sections in 7Li

1977 ◽  
Vol 55 (5) ◽  
pp. 428-433 ◽  
Author(s):  
H. Ferdinande ◽  
N. K. Sherman ◽  
K. H. Lokan ◽  
C. K. Ross
Keyword(s):  
Fine Structure ◽  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Reasonable Agreement ◽  
Branching Ratio ◽  
Energy Spectra ◽  
Average Value ◽  
First Excited State

Photoneutron energy spectra from 7Li have been measured by time-of-flight methods, for bremsstrahlung end-point energies increasing in 2 MeV steps from 13 to 25 MeV. The ground-state and approximate first-excited-state differential cross sections at 90° have been obtained from 8.5 to 23 MeV. No pronounced fine structure has been observed. The measured branching ratio to the first excited state falls from an average value of 0.70 between 10.3 and 14.5 MeV to an average of 0.29 between 14.5 and 18 MeV, and rises again to an average of 0.38 between 18 and 23 MeV. This behaviour can be explained by a crude theoretical model in which 1p → 2s and 1p → 1d single particle transitions dominate below 18 MeV. The calculation predicts a branching ratio of 0.50 near threshold, falling to 0.23 at higher energies, in reasonable agreement with the experiment. The integrated value of the ground-state cross section up to 23 MeV is about (38.7 ± 3.9) MeV mb, while that for the first excited state is about (17.2 ± 3.4) MeV mb. Together they account for 39% of the exchange-augmented dipole sum of 7Li.

Photoneutrons from 20Ne

1975 ◽  
Vol 53 (8) ◽  
pp. 795-801 ◽  
Author(s):  
J. G. Woodworth ◽  
J. W. Jury ◽  
K. H. Lokan ◽  
N. K. Sherman
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Ground State ◽  
Giant Dipole Resonance ◽  
Time Of Flight ◽  
Photon Absorption ◽  
Absolute Cross Section ◽  
Energy Distributions ◽  
Dipole Resonance ◽  
Integrated Cross Section

Photoneutron energy distributions from a target of liquid neon have been measured at 90° by time of flight for bremsstrahlung endpoint energies increasing in 1 MeV steps from 19 to 32 MeV. The differential ground state cross section for the major (91%) isotope 20Ne has been obtained, together with an estimate of the strength of transitions to excited states of 19Ne. Six photoneutron groups are observed, reflecting photon absorption which correlates excellently with existing photoproton data, although the absolute cross section is about 10% smaller.It is noted that the giant dipole resonance, estimated by combining the photoneutron and photoproton data, is centered at approximately 20 MeV, which is anomalously low, and that the integrated cross section up to 28 MeV exhausts only half of the dipole sum.

scholarly journals GDR Contribution to Coulomb Excitation. II. 17O

1982 ◽  
Vol 35 (3) ◽  
pp. 301 ◽  
Author(s):  
FC Barker
Keyword(s):  
Excited State ◽  
Shell Model ◽  
Excited States ◽  
Giant Dipole Resonance ◽  
Coulomb Excitation ◽  
Dipole Resonance ◽  
First Excited State ◽  
Virtual Excitation

The contribution to the Coulomb excitation of the first excited state of 170 due to virtual excitation of the giant dipole resonance (GDR) is calculated, using shell model wavefunctions for the ground and first excited states. A large value is obtained.

The 11B(d,γ0)13C reaction in the region of the giant dipole resonance

1981 ◽  
Vol 59 (6) ◽  
pp. 781-783 ◽  
Author(s):  
G. Kajrys ◽  
W. Del Bianco ◽  
J. Kim ◽  
S. Landsberger ◽  
R. Lecomte ◽  
...  
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Giant Dipole Resonance ◽  
Yield Curve ◽  
Plastic Scintillator ◽  
Resonant Structure ◽  
Crystal Spectrometer ◽  
Dipole Resonance ◽  
Γ Rays

The 90° differential cross section of the 11B(d,γ0)13C reaction has been measured at deuteron energies from 1.95 to 12.0 MeV in steps varying from 100 to 200 keV. The γ-rays have been detected by a 23 cm long × 23 cm diameter NaI(Tl) crystal spectrometer enclosed in a plastic scintillator anticoincidence shield. The yield curve shows a resonant structure at the energies Eexe = 20.4 ± 0.1 and 22.0 ± 0.2 MeV.

scholarly journals Measurements of n?g Coincidences in the Reaction 10B (d, n?)11C

1960 ◽  
Vol 13 (2) ◽  
pp. 99 ◽  
Author(s):  
JA McDonell ◽  
DG Sargood ◽  
JR Moroney ◽  
JR Prescott
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
State Transitions

The energies of some neutron groups leading to low excited states of "C in the reaction lOB(d,ny)"C have been measured. These lead to values of 4�3�0�3 MeV and 6�53 � O' 02 MeV for the energies of the second and fourth excited states respectively. y-Ray spectra have also been studied in coincidence with different neutron groups. Ground state transitions were observed from the second, third, and fourth excited states, together with cascade decays of the fourth excited state through each of the second and third. Deductions from these y-ray spectra considerably reduce the number of spin possibilities which have been found for these levels by other workers.

scholarly journals Constraining the in-medium nucleon-nucleon cross section from the width of nuclear giant dipole resonance

2020 ◽  
Vol 807 ◽  
pp. 135532 ◽  
Author(s):  
Rui Wang ◽  
Zhen Zhang ◽  
Lie-Wen Chen ◽  
Che Ming Ko ◽  
Yu-Gang Ma
Keyword(s):  
Cross Section ◽  
Giant Dipole Resonance ◽  
Nucleon Nucleon ◽  
Dipole Resonance

A generalized empirical formula for half-lives of alpha-decay fine structure

2019 ◽  
Vol 28 (08) ◽  
pp. 1950067
Author(s):  
I. Sreeja ◽  
M. Balasubramaniam
Keyword(s):  
Experimental Data ◽  
Fine Structure ◽  
Ground State ◽  
Empirical Formula ◽  
Daughter Nucleus ◽  
Alpha Decay ◽  
Parent Nucleus ◽  
State Formula ◽  
Model Independent ◽  
Proton Radioactivity

A model-independent and [Formula: see text]-dependent four parameter formula has been recently proposed for the studies of one proton and two proton radioactivity. The same form of the formula with different parameter sets worked well for 1p and 2p emission indicating the fact that the similar phenomenological law is able to successfully reproduce both 1p as well as 2p emission half-lives suggesting the identical descriptions of these phenomena. Retaining the same form of the formula, its applicability is studied in this work for calculating the ground state as well as excited state [Formula: see text] emission. For this study, we consider 22 odd–odd nuclei, 31 odd–even nuclei, 52 even–odd nuclei, 88 even–even nuclei with the parent nucleus charge numbers in the range of [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively. For each of these subsets the emission of [Formula: see text] with different angular momentum values are considered. The general formula with four different parameter sets is proposed and the obtained results are compared with the experimental data. The study reveals that the general form of the proposed empirical formula is suitable for calculating the half-lives of 1p, 2p and [Formula: see text]-emission with different [Formula: see text]-values. With very minimal input like [Formula: see text]-values, and charge number of the daughter nucleus, this formula can be used as a handy tool for a systematic study as well as to plan new experiments.

scholarly journals LBA observations of OH masers in the star-forming region OH 330.953–0.182

2007 ◽  
Vol 3 (S242) ◽  
pp. 162-163
Author(s):  
B. Hutawarakorn Kramer ◽  
J. L. Caswell ◽  
A. Sukom ◽  
J. E. Reynolds
Keyword(s):  
Magnetic Field ◽  
Excited State ◽  
Ground State ◽  
State Transitions ◽  
Star Forming ◽  
Left Hand ◽  
Physical Conditions ◽  
Star Forming Regions ◽  
Long Baseline ◽  
Right And Left Hand

AbstractOH masers are sensitive probes of the kinematics, physical conditions, and magnetic fields in star-forming regions. The maser site OH 330.953-0.182 has been studied using the Long Baseline Array of the Australia Telescope National Facility. Simultaneous observations of the 1665- and 1667-MHz hydroxyl ground-state transitions yield a series of maps at velocity spacing 0.09kms−1, in both right- and left-hand circular polarization, with tenth-arcsec spatial resolution. Several clusters of maser spots have been detected within a five-arcsec region. Eight Zeeman pairs were found, and in one case, at 1665 MHz, there is a nearby 1667-MHz pair indicating a similar value of magnetic field and velocity. Over the whole site, all magnetic field estimates are toward us (negative), and range from -3.7 to -5.8 mG. We also compared the morphology and kinematics of the 1665- and 1667-MHz maser spots with those from the excited state of OH at 6035 MHz and from methanol at 6668 MHz.

Erbium Doped Tellurite Glasses

1991 ◽  
Vol 244 ◽  
Author(s):  
Jau-Sheng Wang ◽  
Elias Snitzer ◽  
George H. Sigel
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Optical Transition ◽  
Emission Cross Section ◽  
Excited State Absorption ◽  
Tellurite Glasses ◽  
Ground State Absorption ◽  
Erbium Doped

ABSTRACTThe results to be presented focus on the optimization of tellurite glass compositions which are suitable both for doping with erbium oxide as well as subsequent for fiber drawing. The laser related properties, such as fluorescence spectrum, lifetime, and optical transition cross sections will be presented. Judd-Ofelt parameters for erbium in the glasses have been exploited to predict fluorescence lifetime, excited state absorption(ESA), ground state absorption(GSA) and ground state fluorescence(GSF). For comparison, the absorption cross section, emission cross section, excited state absorption(ESA)/ground state absorption(GSA)(0.8μm pumping) and fluorescence terminating in the ground state(GSF)/excited state absorption(ESA) ratios are calculated for both Al2O3-SiO2 and tellurite glasses.

Sign in / Sign up

Export Citation Format

Share Document