CAPTURE RADIATION AND NEUTRONS FROM THE BOMBARDMENT OF C14 WITH PROTONS

1955 ◽  
Vol 33 (8) ◽  
pp. 441-456 ◽  
Author(s):  
G. A. Bartholomew ◽  
F. Brown ◽  
H. E. Gove ◽  
A. E. Litherland ◽  
E. B. Paul
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Total Yield ◽  
Isotopic Spin ◽  
Proton Bombardment ◽  
Neighboring State ◽  
Γ Rays ◽  
Γ Ray

The yield and angular distribution of ground state γ-rays and of neutrons resulting from the proton bombardment of C14 have been studied for proton energies from 0.2 to 2.5 Mev. Assignments of spin and parity are made to most of the resonances observed in this range. A single particle proton state which may have isotopic spin 3/2 has been observed. The interference of this state, which has spin 1/2+, with a neighboring state of the same spin and parity is observed in the total yield of the ground state γ-ray. Three states below the neutron threshold which have been observed previously in the N14(d, p)N15 reaction are also observed in the C14(p, γ)N15 reaction. The N14(n, p)C14 cross section at thermal energies can be accounted for by a resonance observed in this experiment, but another resonance below the neutron threshold must be assumed to account for the thermal (n, n) and (n, γ) cross sections.

Angular distribution of the 3H(p,γ)4He reaction at proton energies below 1 MeV

1980 ◽  
Vol 58 (10) ◽  
pp. 1496-1499 ◽  
Author(s):  
W. Del Bianco ◽  
G. Kajrys
Keyword(s):  
Angular Distribution ◽  
Differential Cross Section ◽  
Cross Section ◽  
Differential Cross ◽  
Angular Range ◽  
Γ Rays ◽  
Γ Ray ◽  
Energy Dependent

The differential cross section of the 3H(p,γ)4He reaction has been measured at the proton energies Ep = 0.46, 0.50, 0.62, 0.77, and 0.93 MeV. A thin 3H–Ti target has been used and the γ-rays have been detected by a 12.7 cm diameter × 15.2 cm long NaI(Tl) crystal rotating over the angular range θL = 0 to 135°. The 3H(p,γ)4He reaction is found to proceed through E1, M1, and E2 transitions, E1 transitions being predominant. The ratio of the γ-ray flux at θL = 0 and 90° is energy dependent and decreases from 0.017 ± 0.003 at Ep = 0.46 MeV to 0.0078 ± 0.006 at Ep = 0.93 MeV.

Ground-state and isomeric-state cross-sections for 92Mo(n,α)89Zr and 95Mo(n,p)95Nb reactions in the 13–15 MeV energy region

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Junhua Luo ◽  
Li Jiang
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Nuclear Decay ◽  
Excitation Functions ◽  
Total Cross Sections ◽  
Γ Ray ◽  
Simulation Results ◽  
The Cross ◽  
Isomeric Ratios

Abstract The (n,α) and (n,p) cross-sections and their isomeric ratios (σ m /σ g ) were measured at 13–15 MeV for 92Mo and 95Mo by activation and off-line γ-ray spectrometry. The activated Mo samples combined with Al foils were used to obtain the cross-section values and the neutron flux, generated using the 3H(d,n)4He reaction. The cross-sections of the ground states were obtained using the metastable state absolute cross-sections and the residual nuclear decay rule. The excitation functions, total cross-sections, and isomeric ratios for the 92Mo(n,α)89m,gZr and 95Mo(n,p)95m,gNb reactions were calculated using the TALYS-1.95 software. 92Mo(n,α)89m + gZr and 95Mo(n,p)95m + gNb reaction excitation functions were obtained using the EMPIRE-3.2.3 package. These simulation results were compared with the corresponding experimental data and with the evaluated data from the ENDF/B-VIII.0, JEFF-3.3, CENDL-3, and ROSFOND libraries. Only partial agreements were observed.

scholarly journals Non-central interactions between neutron and proton

1949 ◽  
Vol 196 (1045) ◽  
pp. 135-159 ◽  
Keyword(s):  
Binding Energy ◽  
Cross Section ◽  
Magnetic Moment ◽  
Ground State ◽  
High Energy ◽  
Isotopic Spin ◽  
Shape Functions ◽  
Low Velocity ◽  
Exchange Operator ◽  
Γ Rays

Calculations are carried out concerning the magnetic moment of the deuteron, the scattering of neutrons with energies up to 20 MeV by protons and the photodisintegration of deuterons by high energy (17 to 20 MeV) γ-rays assuming various non-central interactions between neutron and proton of the form V = -½ -⅓τ.τ 2 (1 1 +τ 1 .τ 2 ) {- h 2 / M a / r 0 2 [ 1+½ g (σ 1 . σ 2 -1)+γ(3σ 1 rσ 2 .r/ r 2 -σ 1 .σ 2 )]} V ( r / r 0 ), where σ 1 , σ 2 , τ 1 , τ 2 are the spin and isotopic spin operators of the particles, r the distance between them. For three ̔shape’ functions V (spherical well, exponential and Yukawa forms) the constants a , g , γ are determined for different values of the range r 0 , so as to give correctly the binding energy of the ground state, and the quadrupole moment, of the deuteron and the low velocity neutron-proton cross-section. Calculations are then carried out for chosen values of r 0 and the three forms of the exchange operator for each shape. A comparison is made of the ranges derived from different data for each of the shapes considered.

scholarly journals Photoionisation Cross Sections of Chlorine Atoms and Molecules at 584 Å

1986 ◽  
Vol 39 (5) ◽  
pp. 779 ◽  
Author(s):  
WJ van der Meer ◽  
RJ Butselaar ◽  
CA de Lange
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Modulation Method ◽  
Absolute Cross Section ◽  
Molecular Chlorine ◽  
Chlorine Atoms ◽  
Atoms And Molecules ◽  
Ionic States ◽  
State Ionic

A recently developed modulation method is used to obtain cross sections for the photoionisation of ground state neutral to ground state ionic, atomic and molecular chlorine relative to that of the HCl + (X2n 1IZ,3IZ) +-- HCl(XI ~ +) transition at the He Ia wavelength. With the known absolute cross section of the latter process, determined by (e,2e) coincidence spectroscopy, the present ell,periments provide absolute photoionisation cross sections of the CI + epz,l,o) +-- Clep) and Cli (XZ n g, 1IZ,3 IZ) +-- Clz (X I ~ t) transitions. Relative cross sections, previously determined for the transitions to the additional Cl and Clz ionic states accessible with He Ia radiation, are used to obtain absolute cross sections for the Cl+(IDz, ISO) +-- Clep) and Cli(AZnu,1IZ,3IZ, BZ~t) +-- Clz(XI~t) ionisation processes.

scholarly journals Spatial Non-uniformity in Discharges in Low Pressure Helium and Neon

1987 ◽  
Vol 40 (3) ◽  
pp. 383 ◽  
Author(s):  
J Fletcher ◽  
PH Purdie
Keyword(s):  
Monte Carlo Simulation ◽  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Low Pressure ◽  
Photon Flux ◽  
Cross Section Data ◽  
Section Data ◽  
Neon Gas ◽  
Wavelength Distribution

Low current, low pressure, steady state Townsend discharges in helium and neon gas have been investigated using the photon flux technique. Such discharges have been found to exhibit spatial non-uniformity resulting in luminous layers throughout the discharge. The separation and structure of these layers has been investigated experimentally in both gases along with the wavelength distribution of the photon flux. A Monte Carlo simulation of the discharge in neon has been used to gain information on the cross sections necessary to describe these discharges. It is found that direct excitaton of ground state atoms to the resonance level of each gas is less than indicated by some published cross section data.

Cross section for the excitation of helium by protons

1979 ◽  
Vol 57 (8) ◽  
pp. 1174-1177
Author(s):  
S. P. Ojha ◽  
P. Tiwari
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Proton Impact ◽  
Experimental Findings

Cross sections for the singlet excitation of helium by proton impact have been computed using the Vainshtein, Presnyakov, and Sobelman (VPS) method with peaking approximation. Transitions from the ground state to the n1P(n = 2, 3, and 4) states have been taken into account. The results are compared with other theoretical and experimental findings.

ENERGIES AND HALF-LIVES OF ISOMERIC LEVELS IN THE NUCLEI 139Ce, 141Nd, 161Ho, AND 163Ho

1967 ◽  
Vol 45 (7) ◽  
pp. 2281-2293 ◽  
Author(s):  
J. S. Geiger ◽  
R. L. Graham
Keyword(s):  
Internal Conversion ◽  
Rotational Transition ◽  
Proton Bombardment ◽  
Conversion Electrons ◽  
Transition Energies ◽  
Γ Rays ◽  
Γ Ray ◽  
Internal Conversion Electrons

A search has been made for delayed γ rays with 1 second [Formula: see text] minutes following 10.5-MeV proton bombardment of 18 natural metallic targets. The five activities observed are: (1) 139Ce, Eγ = 754.5 ± 1.3 keV, [Formula: see text] second; (2) 141Nd, Eγ = 756.8 ± 1.3 keV, [Formula: see text] second; (3) 161Ho, Eγ = 211 ± 2 keV, [Formula: see text] second; (4) 163Ho, Eγ = 299 ± 2 keV, [Formula: see text] second; and (5) a γ ray of 122 ± 2 keV, [Formula: see text] second which is tentatively assigned to 179Ta. All transitions have been measured using a Ge(Li) γ-ray detector. The internal conversion electrons of the transitions in 139Ce and 141Nd were also studied using an orange β-ray spectrometer. Rotational transition energies in 158Dy, 164Er, 168Yb, and 174Hf were measured in conjunction with the internal conversion studies and are reported in an Appendix.

GAMMA RADIATION FROM THE PROTON BOMBARDMENT OF BORON TEN

1956 ◽  
Vol 34 (4) ◽  
pp. 381-388 ◽  
Author(s):  
G. B. Chadwick ◽  
T. K. Alexander ◽  
J. B. Warren
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Gamma Rays ◽  
Lower Energy ◽  
Sodium Iodide ◽  
Scintillation Counter ◽  
Proton Bombardment ◽  
Broad Resonance ◽  
Energy Formula ◽  
Cascade Transitions

The gamma rays resulting from the bombardment of B10 with protons of energies from 0.5 to 2.0 Mev. have been observed with a sodium iodide scintillation counter. Capture radiation, of energy[Formula: see text]showed a broad resonance at Ep = 1135 ± 15 kev. At this energy, the radiation had an angular distribution of the form 1 + (0.50 ± 0.05)cos2θ and a total cross section (3.5 ± 1.0)10−30 cm.2 Several lower energy radiations were also observed and assigned tentatively to cascade transitions in C11.The cross section for the 430 kev. radiation from the reaction B10(p, αγ)Be7 was found to be 0.21 ± 0.05 barn at Ep = 1.52 Mev. This radiation was found to be isotropic.

scholarly journals Radiocarbon Production by the Gamma-Ray Component of Supernova Explosions

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 599-604 ◽  
Author(s):  
Paul E. Damon ◽  
Dai Kaimei ◽  
Grant E. Kocharov ◽  
Irina B. Mikheeva ◽  
Alexei N. Peristykh
Keyword(s):  
Cross Section ◽  
Tree Rings ◽  
Confidence Level ◽  
Gamma Ray ◽  
Visual Observation ◽  
Total Production ◽  
Average Increase ◽  
Supernova Explosions ◽  
Γ Rays ◽  
Γ Ray

We selected SN1006, the brightest and closest to Earth of all supernovas historically observed, for a study of 14C production by e−,e+-bremsstrahlung cascades initiated by hard γ rays (>10 MeV) from that event. During the cascade, bremsstrahlung energies eventually fall within a giant (n,γ), (n,2γ) cross-section, peaking at 23 MeV and approaching effectively zero below 10 MeV and above 40 MeV. The neutrons are absorbed primarily in the reaction 14N(n,p)14C. Cellulose from single-year tree rings from ad 1003 to ad 1020 was measured to determine ∆14C. Three years after the first visual observation of SN1006, ∆14C rose and remained above pre-ad 1009 values until ad 1018. Comparison of the 7 years before ad 1009 with the 9 years following show an average increase of 6.1 ± 1.6 (s.d.)‰ (significant at the 99.6% confidence level). Such a pulse of 14C requires a total production of neutrons of 17.1 × 107n cm−2e, implying an input of 11.3 × 104 ergs cm−2e γ-ray energy. This requires the total supernova γ-ray energy (>10 MeV) to have been 1 × 1050 ergs.

QUASI-CLASSICAL TRAJECTORY STUDY OF THE REACTION PROBABILITY AND CROSS SECTION OF THE REACTION LiH + H

2013 ◽  
Vol 12 (01) ◽  
pp. 1250093 ◽  
Author(s):  
YULIANG WANG ◽  
JINCHUN ZHANG ◽  
BAOGUO TIAN ◽  
KUN WANG ◽  
XIAORUI LIANG ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Collision Energy ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Reaction Cross ◽  
Reaction Probability ◽  
Title Reaction ◽  
Reaction Cross Sections

Based on the new accurate potential energy surface of the ground state of LiH2 system. Quasi-classical trajectory (QCT) calculations were carried out for the reaction LiH + H . The reaction probability of the title reaction for J = 0 has been calculated. The reaction cross sections were calculated as functions of the collision energy in the range 0.1–2.5 eV. The results were found to be well consistent with the previous real wave packet (RWP) and QCT results.

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