PHOTONEUTRON THRESHOLD AND CROSS SECTION FOR 71Lu175

1958 ◽  
Vol 36 (4) ◽  
pp. 415-418 ◽  
Author(s):  
H. J. King ◽  
L. Katz
Keyword(s):  
Cross Section ◽  
Neutron Yield ◽  
Giant Resonance ◽  
Threshold Energy ◽  
Half Width ◽  
Bremsstrahlung Energy ◽  
Resonance Cross Section ◽  
Integrated Cross Section ◽  
Peak Value

The neutron yield resulting from photoneutron reactions in Lu175 has been measured as a function of peak bremsstrahlung energy up to 23 Mev. The threshold energy for this reaction was found to be 7.77 ± 0.05 Mev. The giant resonance cross section has a peak value of 225 millibarns at 16 Mev., a half-width of 8.4 Mev., and an integrated cross section to 23 Mev. of 1.9 Mev-barns.

PHOTONEUTRON CROSS SECTIONS IN SILICON AND CALCIUM

1953 ◽  
Vol 31 (1) ◽  
pp. 70-77 ◽  
Author(s):  
R. G. Summers-Gill ◽  
R. N. H. Haslam ◽  
L. Katz
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Neutron Yield ◽  
Threshold Energy ◽  
Threshold Effect ◽  
Monitoring Method ◽  
Dose Monitoring ◽  
Γ Rays ◽  
Integrated Cross Section ◽  
Peak Value

Using the dropping apparatus and dose monitoring method previously reported, the cross sections for the reactions Si28(γ, n)Si27 and Ca40(γ, n)Ca39 have been measured by detecting positron activities in the residual nuclei. The Si28(γ, n)Si27 cross section has a peak value of 21 mbarns at 20.9 Mev. and an integrated cross section to 24 Mev. of 0.070 Mev-barns. The threshold energy is 16.9 ± 0.1 Mev. The Ca40(γ, n)Ca39 cross section has a peak value of 15 mbarns at 19.3 Mev. and an integrated cross section to 24 Mev. of 0.065 Mev-barns. The threshold is 15.8 ± 0.1 Mev.A comparison of our results with the neutron yield measurement of Price and Kerst at 18 and 22 Mev. gives good agreement. A further comparison with the neutron yield work of Baldwin and Elder is made.The sharp discontinuity in (γ, n) yields using lithium γ rays observed by Wäffler and Hirzel is explained as a threshold effect. Integrated cross sections increase more or less smoothly with Z.In addition, improved values for the half-lives of the residual nuclei Si27 and Ca39 have been measured. These are 4.45 ± 0.05 and 1.00 ± 0.03 sec. respectively.

THE MEASUREMENT OF PHOTONUCLEAR CROSS SECTIONS IN ISOTOPES LEADING TO SHORT-LIVED DECAY PRODUCTS

1952 ◽  
Vol 30 (3) ◽  
pp. 257-269 ◽  
Author(s):  
R. N. H. Haslam ◽  
R. G. Summers-Gill ◽  
E. H. Crosby
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Half Life ◽  
Half Width ◽  
Reaction Threshold ◽  
Parent Materials ◽  
Dosage Rate ◽  
Decay Products ◽  
Integrated Cross Section ◽  
Peak Value

A dropping apparatus, including a new means of dosage rate monitoring, has been designed to allow the observation of short-lived activities produced by betatron irradiation of various parent materials. The photonuclear cross section for the reaction S32(γ, n)S31 has been measured by this means. The cross section has a peak value of 24.6 millibarns at 20.1 ± 0.5 Mev., a half width of 4.5 Mev., and an integrated cross section of 0.12 Mev-barns. The reaction threshold was found to be 15.0 ± 0.1 Mev. The experiment has also yielded a new half life for S31 − 2.66 ± 0.03 sec.

CROSS SECTION FOR THE REACTION Be9(γ, p)Li8

1953 ◽  
Vol 31 (2) ◽  
pp. 210-217 ◽  
Author(s):  
R. N. H. Haslam ◽  
L. Katz ◽  
E. H. Crosby ◽  
R. G. Summers-Gill ◽  
A. G. W. Cameron
Keyword(s):  
Cross Section ◽  
Half Width ◽  
X Ray ◽  
Intermittent Operation ◽  
Integrated Cross Section ◽  
The Cross ◽  
Peak Value

The reaction Be9(γ, p)Li8has been investigated by detecting the 0.88 sec. Li8 β-activity, by the use of a cycling apparatus which allows intermittent operation of the betatron, counting taking place during the periods of no X-ray yield. The cross section for the reaction has a peak value of 2.72 mbarns at 22.2 Mev., a half-width of 4.7 Mev., and the integrated cross section to 26 Mev. is 0.013 Mev-barns.

Photoneutron Cross Sections in 14N

1972 ◽  
Vol 50 (15) ◽  
pp. 1689-1696 ◽  
Author(s):  
R. W. Gellie ◽  
K. H. Lokan ◽  
N. K. Sherman ◽  
R. G. Johnson ◽  
J. I. Lodge
Keyword(s):  
Excited States ◽  
Cross Section ◽  
Cross Sections ◽  
Neutron Emission ◽  
Giant Resonance ◽  
Sequential Decay ◽  
Dipole Resonance ◽  
Intermediate States ◽  
Integrated Cross Section ◽  
High Degree

Photoneutron distributions from 14N have been obtained by time-of-flight methods, for bremsstrahlung end-point energies increasing in 2 MeV steps from 15.5 to 29.5 MeV. A large part of the neutron yield is associated with the sequential decay of 14N to 12C, through well-defined intermediate states of 13C, at 7.55, 8.86, and 11.80 MeV, which are unstable against neutron emission. The (γ,n0) cross section for neutron emission to the ground state of 13N is found to agree very closely with the corresponding (γ,p0) cross section, implying a high degree of isospin purity for the giant dipole resonance of 14N. It is observed that the decay of the giant resonance proceeds freely through those odd-parity excited states of the A = 13 nuclei which are single hole states formed by the removal of a p-shell nucleon from the parent 14N.The integrated cross section for all neutron-producing interactions is found to be 88 ± 5 MeV mb.

THE GAMMA-NEUTRON CROSS SECTION FOR N14

1960 ◽  
Vol 38 (2) ◽  
pp. 231-239 ◽  
Author(s):  
J. D. King ◽  
R. N. H. Haslam ◽  
R. W. Parsons
Keyword(s):  
Theoretical Prediction ◽  
Cross Section ◽  
Sodium Iodide ◽  
Giant Resonance ◽  
Residual Activity ◽  
Neutron Cross Section ◽  
Resonance Region ◽  
X Ray ◽  
Integrated Cross Section ◽  
Iodide Crystal

The reaction N14(γ,n)N13 has been studied by irradiating dicyandiamide in the X-ray beam of a 25-Mev betatron and measuring the residual activity with a sodium iodide crystal system. The photoneutron cross section shows maxima at 11.7, 13.2, 15.2, 19.5, and 22.8 Mev, the last two being in the giant resonance region. The integrated cross section from threshold to the beginning of the giant resonance region is 1.8 Mev-mb, and this is compared with a recent theoretical prediction. During the course of the experiment, accurate measurements were made of the half-life of N13 and it was found to be 9.93 ± 0.05 minutes.

THE (γ, n) AND (γ, p) CROSS SECTIONS OF ARGON40

1954 ◽  
Vol 32 (9) ◽  
pp. 593-598 ◽  
Author(s):  
D. McPherson ◽  
E. Pederson ◽  
L. Katz
Keyword(s):  
Cross Section ◽  
Photon Energy ◽  
Cross Sections ◽  
Integrated Cross Section ◽  
Peak Value

The (γ, n) and (γ, p) cross sections in A40 have been measured as a function of photon energy from threshold to 24 Mev. The (γ, n) cross section was found to have a peak value of 38 mbarns at 20 Mev. and an integrated cross section of 0.35 Mev-barn. These values for the (γ, p) cross section were found to be 120 mbarns at > 25 Mev. and 0.54 Mev-barn respectively. In spite of the higher (γ, p) threshold, it was found that the two cross sections were equal at 19.5 Mev. and above this energy the (γ, p) cross section became larger. This interesting result is discussed.

scholarly journals Qualification of Operational Amplifier used in Satellite Subsystem using Picosecond Pulsed Laser System

2020 ◽  
Vol 9 (2) ◽  
pp. 523-527
Keyword(s):  
Cross Section ◽  
Operational Amplifier ◽  
Second Harmonic ◽  
Laser System ◽  
Threshold Energy ◽  
Pulsed Laser ◽  
Spot Size ◽  
Single Event ◽  
532 Nm ◽  
Pulsed Laser Irradiation

Picosecond Pulsed Laser System (PPLS) was used to simulate the single event effects (SEE) on satellite electronic components. Single event transients effect induced in an operational amplifier (LM324) to determine how transient amplitude and charge collection varied with pulsed laser energies. The wavelength and the focused spot size are the primary factors generating the resultant charge density profile. The degradation performance of LM324 induced by pulsed laser irradiation with two wavelength (1064nm, 532nm) is determined as a function of laser cross section. The transient voltage changed due to pulsed laser hitting specific transistors. This research shows the sensitivity mapping of LM324 under the effect of fundamental and second harmonic wavelengths. Determine the threshold energy of the SET in both wavelength, and compare the laser cross section of 1064 nm beam and 532 nm beam.

A source of experimental underestimation of aerosol bolus deposition

1999 ◽  
Vol 86 (3) ◽  
pp. 1067-1074 ◽  
Author(s):  
S. Verbanck ◽  
C. Darquenne ◽  
G. K. Prisk ◽  
W. Vincken ◽  
M. Paiva
Keyword(s):  
Measurement Error ◽  
Cross Section ◽  
Delivery System ◽  
Delivery Systems ◽  
Half Width ◽  
Aerosol Concentration ◽  
Particle Counter ◽  
Incomplete Mixing

We examined the measurement error in inhaled and exhaled aerosol concentration resulting from the bolus delivery system when small volumes of monodisperse aerosols are inspired to different lung depths. A laser photometer that illuminated ∼75% of the breathing path cross section recorded low inhaled bolus half-widths (42 ml) and negative deposition values for shallow bolus inhalation when the inhalation path of a 60-ml aerosol was straight and unobstructed. We attributed these results to incomplete mixing of the inhaled aerosol bolus over the breathing path cross section, on the basis of simultaneous recordings of the photometer with a particle-counter sampling from either the center or the edge of the breathing path. Inserting a 90° bend into the inhaled bolus path increased the photometer measurement of inhaled bolus half-width to 57 ml and yielded positive deposition values. Dispersion, which is predominantly affected by exhaled bolus half-width, was not significantly altered by the 90° bend. We conclude that aerosol bolus-delivery systems should ensure adequate mixing of the inhaled bolus to avoid error in measurement of bolus deposition.

Sign in / Sign up

Export Citation Format

Share Document