Photoneutron Reactions in 18O

1975 ◽  
Vol 53 (8) ◽  
pp. 786-794 ◽  
Author(s):  
J. D. Allan ◽  
J. W. Jury ◽  
R. G. Johnson ◽  
K. G. McNeill ◽  
J. G. Woodworth ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Ground State ◽  
Energy Spectra ◽  
Continuum State ◽  
Average Value ◽  
First Excited State ◽  
Time Of Flight Spectroscopy

Photoneutron energy spectra from 18O have been measured by time-of-flight spectroscopy at bremsstrahlung endpoint energies from 11 to 18 MeV in 1 MeV steps to obtain the (γ, n0) and (γ, n1) differential cross sections. The ground state photoneutron cross section contains at least 8 major resonances in the region from 10 to 17 MeV and has an average value of 100 μb/sr. The cross section to the first excited state of 17O contains only two major resonances, at 11.4 and 14.4 MeV, and the average cross section in the region from 11 to 16 MeV is about 40 μb/sr. Of particular interest is a resonance at 14.4 MeV which appears to reflect a simple excitation of one of the valence neutrons to the 2p3/2 state. Analysis of the (γ, n0) and (γ, n1) cross sections for this continuum state leads to estimates of the configuration amplitudes of the 2s1/2 and 1d5/2 components of this state to be 0.62 ± 0.06 and 0.78 ± 0.08 respectively and the ratio of the (2s1/2)2 to (1d5/2)2 amplitudes in the ground state of 18O to be 0.39 ± 0.02.

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.

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.

scholarly journals Copper and sulphur depth profile in patina layers using NRA and RBS

2019 ◽  
Vol 11 ◽  
Author(s):  
G. Kalliabakos ◽  
S. Kossionides ◽  
P. Misailides ◽  
C. T. Papadopoulos ◽  
R. Vlastou
Keyword(s):  
Excited State ◽  
Cross Sections ◽  
Ground State ◽  
Depth Distribution ◽  
Nuclear Reaction Analysis ◽  
Beam Direction ◽  
The Third ◽  
First Excited State ◽  
Γ Ray

A combination of nuclear reaction analysis (NRA) and Rutherford backscattering spectroscopy (RBS) were utilized in order to obtain information on the depth distribution of sulphur and copper in artificially produced and natural patina layers. The copper profiling was performed by using the reaction 63Cu(p,p'y)6 3Cu and detecting the 1327 keV γ-ray deexciting the third excited state to the ground state of 6 3Cu produced. For the determination of sulfur the 2230 keV γ-ray was used, deexciting the first excited state to the ground state of 32S formed through the reaction 3 2S(p,p'y)3 2S, which exhibits three sharp resonances at projectile energies 3.094, 3.195 and 3.379 MeV. The relevant cross-sections were measured in the energy range between 3.0 and 3.7 MeV in steps of 20 keV at 125° to the incident proton beam direction. Supporting information on the depth distribution of oxygen and the other elements of the patina samples was obtained by p-RBS (Ep = 1.5 MeV; θ = 160°).

scholarly journals Determination of Sulfur and Copper Profile with nuclear reactions

2019 ◽  
Vol 10 ◽  
pp. 1
Author(s):  
S. Kossionides ◽  
G. Kaliambakos ◽  
R. Vlastou ◽  
C. T. Papadopoulos
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Ground State ◽  
Nuclear Reactions ◽  
Nuclear Reaction Analysis ◽  
The Third ◽  
First Excited State ◽  
Γ Ray ◽  
Resonant Reaction

The concentration and depth profile of Cu and S in patinna samples have been determined by using Nuclear Reaction Analysis (NRA) and Rutherford Backscattering Spectroscopy (RBS). For the NRA the differential cross section was mesaured for the 1327 keV 7-ray deexciting the third excited state to the ground state of 6 3Cu through the reaction 63Cu(p,p'7), as well as, for the 2230 keV γ-ray deexciting the first excited state to the ground state through the resonant reaction 32S(p,p'7). The mesaurements of both excitation functions were performed in the energy range 3.0 - 3.7 MeV in 20 keV steps and at an angle of 125°.

The high-order optical nonlinearity of 2,11,20,29-tetrabromo-2,3-naphthalocyanine iron

2018 ◽  
Vol 22 (09n10) ◽  
pp. 863-867
Author(s):  
Wang Zhang ◽  
Chunying He ◽  
Lining Zhang ◽  
Li Jiang ◽  
Yijun Yuan ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Sections ◽  
Ground State ◽  
Nonlinear Refraction ◽  
Optical Nonlinearity ◽  
High Order ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Triplet Excited State ◽  
First Excited State

A novel naphthalocyanine 2,11,20,29-tetrabromo-2,3-naphthalocyanine iron was synthetized. Its optical nonlinearity was investigated using the Z-scan technique. Reverse saturable absorption and high-order optical nonlinear refraction were detected. The absorption cross sections of the ground state, the singlet first excited state and the triplet first excited state were fitted to be 3.2 × 10[Formula: see text] cm[Formula: see text], 6.2 × 10[Formula: see text] cm[Formula: see text] and 4.6 × 10[Formula: see text] cm[Formula: see text], respectively. Fits also gave 1.17 × 10[Formula: see text] cm[Formula: see text] for the refractive volume of the ground state, 0.6 for the ratio of the refractive volume of the singlet first excited state to the ground state and 2.7 for the ratio of refractive volume of the first triplet excited state to the ground state.

Investigation of Fine Structure in the Photoneutron Cross Sections of 16O and 208Pb

1975 ◽  
Vol 53 (15) ◽  
pp. 1434-1442 ◽  
Author(s):  
R. G. Johnson ◽  
J. D. Irish ◽  
K. G. McNeill
Keyword(s):  
Fine Structure ◽  
High Resolution ◽  
Differential Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Center Of Mass ◽  
Energy Spectra ◽  
Neutron Time ◽  
Good Agreement

The structure in the photoneutron cross sections of 16O and 208Pb has been studied by the measurement of high resolution photoneutron energy spectra using the neutron time-of-flight technique and bremsstrahlung irradiations. For 16O, the ground state differential cross section at 98° has been deduced between 17.3 and 28.5 MeV and is in good agreement with most previous studies. Fine structure is seen throughout the cross section. Eight neutron energy spectra for 208Pb from bremsstrahlung endpoint energies in the range 11.0 to 15.5 MeV were obtained. Strong peaks are seen at center of mass neutron energies of 1.67, 1.85, 2.06, 2.19, 2.68, 3.15, 3.27, 3.50, 3.77, and 4.03 MeV with weaker peaks elsewhere. The energies of these peaks are in good agreement with previous measurements in this laboratory. The energies of peaks in the spectra are compared with recent cross section measurements.

scholarly journals PRODUCTION AND SEARCHES FOR CASCADE BARYONS WITH CLAS

2010 ◽  
Vol 19 (12) ◽  
pp. 2410-2417
Author(s):  
◽  
Elton S. Smith
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Invariant Mass Spectrum ◽  
Photon Beam ◽  
Production Mechanism ◽  
Total Cross Sections ◽  
Deuterium Target ◽  
Upper Limits ◽  
First Excited State

We present the results of photoproduction cross sections of the ground state cascade Ξ- and the first excited state Ξ*-(1530) measured with the CLAS detector. The photoproduction of the cascade resonances has been investigated in the reactions γp → K+K+(X) and γp → K+K+π-(X). The differential and total cross sections of the Ξ- were determined for photon beam energies from 2.75 to 4.75 GeV and are consistent with a production mechanism of Y* → K+Ξ- through a t-channel process. The cross-section of the Ξ*-(1530) has been determined for photon beam energies from 3.35 to 4.75 GeV. The reaction γp → K+K+π-(Ξ0) has also been investigated in the search for excited cascade resonances decaying to π-Ξ0. No significant signal of excited cascade states other than the well-known Ξ*-(1530) is observed. We also present the latest results of a search for the Φ--(1862) exotic pentaquark state in a photoproduction experiment on a deuterium target. A high-statistics sample of π-Ξ- events have been collected and analyzed. A preliminary invariant mass spectrum of the π-Ξ- system is presented, which is used to set upper limits on the photoproduction of the Φ-- pentaquark state.

Energy values for some proton and deuteron reactions with 6 Li, 7 Li, 9 Be, 11 B and 15 N

1953 ◽  
Vol 216 (1125) ◽  
pp. 242-246 ◽  
Keyword(s):  
Excited State ◽  
Nuclear Reaction ◽  
Ground State ◽  
Excited Level ◽  
Average Value ◽  
First Excited State ◽  
Reaction Energies ◽  
The Difference

The following values of nuclear reaction energies have been obtained: 6 Li (p,α) 3 He, Q = 4.023 MeV; 8 Li (d ,p) 7 Li, Q = 5.028 MeV; 6 Li (d, p ) 7* Li, Q= 4.553 MeV; 6 Li( d,α ) α, Q = 22.396 MeV; 7 Li (p , α ) α , Q = 17.352 MeV; 9 Be (p, α ) 6 Li, Q = 2.126 MeV; 9 Be (p, d ) 8 Be, Q = 0.560 MeV; 9 B e (d, α ) 7 Li, Q = 7.153 MeV; 9 Be (d, α ) 7* Li, Q = 6.675 MeV; n B (p , α ) 8 Be, Q = 8.589 MeV; 15 N (p, α ) 12 C, Q = 4.962 MeV. The average value of th e first excited level in 7 Li has been found to be 0.477 ± 0.003 MeV from the difference between the ground state and first excited state groups of the 6 Li (d, p) 7 Li and 9 Be (d, α) 7 Li experiments. A comparison is made between the above results and recent figures quoted by other workers in this field, and it is found that no systematic discrepancies are conspicuous, except that our energies are on the average higher than those found at M.I.T. and C.I.T., probably due to the differences between the momentum and energy standards used by these groups of workers and those measured by us.

Measurement of the reorientation effect in 24Mg

1970 ◽  
Vol 48 (1) ◽  
pp. 35-45 ◽  
Author(s):  
O. Häusser ◽  
B. W. Hooton ◽  
D. Pelte ◽  
T. K. Alexander ◽  
H. C. Evans
Keyword(s):  
Excited State ◽  
Matrix Element ◽  
Quadrupole Moment ◽  
Cross Sections ◽  
Ground State ◽  
Coulomb Excitation ◽  
Rotational Model ◽  
First Excited State ◽  
Scattering Cross Sections ◽  
Static Quadrupole

The reorientation effect in Coulomb excitation with 62 MeV 35Cl projectiles was used to measure the static quadrupole moment of the first excited state in 24Mg. From a comparison of the inelastic scattering cross sections at CM scattering angles of 123.1° and 72.8°, a static quadrupole moment of Q = −0.243 ± 0.035 b was deduced. The E2 matrix element connecting the ground state and first excited state was also measured and corresponds to 20.3 ± 1.4 W.u. for the 2+ → 0+ transition. The results are compared with predictions of the rotational model.

ISOSPIN DECOMPOSITION OF pp → NNππ CROSS SECTIONS — DO WE SEE A SIGN OF Δ(1600) EXCITATION IN THE nnπ+π+ CHANNEL?

2009 ◽  
Vol 24 (02n03) ◽  
pp. 450-453
Author(s):  
◽  
T. SKORODKO ◽  
M. BASHKANOV ◽  
D. BOGOSLOWSKY ◽  
H. CALÉN ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Pion Production ◽  
Significant Contribution ◽  
Differential Cross Sections ◽  
Pp Collisions ◽  
Theoretical Predictions ◽  
Order Of Magnitude ◽  
The Cross

The two-pion production in pp-collisions has been investigated in exclusive measurements from threshold up to Tp = 1.36 GeV . Total and differential cross sections have been obtained for the channels pnπ+π0, ppπ+π-, ppπ0π0 and also nnπ+π+. For intermediate incident energies Tp > 1 GeV , i.e. in the region, which is beyond the Roper excitation but at the onset of ΔΔ excitation the total ppπ0π0 cross section falls behind theoretical predictions by as much as an order of magnitude near 1.2 GeV, whereas the nnπ+π+ cross section is a factor of five larger than predicted. A model-unconstrained isospin decompostion of the cross section points to a significant contribution of an isospin 3/2 resonance other than the Δ(1232). As a possible candidate the Δ(1600) is discussed.

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