Neutron yield from the reaction (α, n) in Be, B, C, O, F, Mg, Al, Si, and granite irradiated with polonium α particles

G. V. Gorshkov; V. A. Zyabkin; O. S. Tsvetkov

doi:10.1007/bf01587334

Study on the Measurement of U-238 Neutron Yield Base on the Fission Chamber

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.366.474 ◽

2011 ◽

Vol 366 ◽

pp. 474-477

Author(s):

Ju Mei Ai ◽

Qiang Wang

Keyword(s):

Neutron Yield ◽

Ionization Chamber ◽

Measurement Method ◽

Fission Neutron ◽

Particle Energy ◽

Measuring System ◽

Fission Chamber ◽

Particle Counts ◽

Yield Monitoring ◽

Α Particles

This paper discusses a variety of fission neutron yield measurement method, a D-T / D-D neutron yield monitoring of U-238 fission ionization chamber measuring system, the application of spontaneous decay of U-238 α-particles for initial debugging of the system. At different voltage on the α-particle energy spectrum and α particle counts were measured, given the U-238 fission chamber curve to determine the U-238 fission chamber measurement system the best operating parameters.

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Calculated neutron spectra from 9Be(α, n) sources

Canadian Journal of Physics ◽

10.1139/p68-478 ◽

1968 ◽

Vol 46 (13) ◽

pp. 1527-1536 ◽

Cited By ~ 26

Author(s):

L. Van der Zwan

Keyword(s):

Simple Model ◽

Neutron Spectrum ◽

Neutron Yield ◽

Cluster Size ◽

Energy Losses ◽

Neutron Spectra ◽

N Sources ◽

Similar Peak ◽

Α Particles

The neutron spectra from 9Be(α, n) sources are calculated for the α emitters 241Am, 210Po,and 239Pu. For a Pu–Be source, peaks are found at neutron energies of 0.75, 1.20, 2.10, 3.15, 4.95, 6.50, 7.75, and 9.65 MeV. Similar peak positions are found for sources made with 241Am and 210Po. The effect of the α-energy losses in the α-emitting material is studied by means of a simple model consisting of clusters of the α-emitting material embedded in a matrix of beryllium. For sources composed of clusters of AmBe13 or PuBe13 in beryllium, the changes in shape of the neutron spectrum are minor as the cluster size is increased from 0.5 to 20 μ. However, for sources consisting of clusters of Pu and Am or Po embedded in beryllium, the spectrum is considerably distorted as the cluster size is varied from 0.5 to 10 μ. The neutron yield per 106 α particles is calculated for sources having Am, Po, or Pu clusters ranging in size from 0 to 20 μ and AmBe13 or PuBe13 clusters ranging from 0 to 40 μ. The percentage of neutrons below 1.5 MeV including the contribution from the multiparticle reaction 9Be(α, αn)8 Be is estimated to be 16% for an AmBe13 type of source and 12% for a PuBe13 type of source, each with a cluster size of 0.5 μ.

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Alignment of small He-Bubbles during in situ deformation of Al-foils

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109124 ◽

1978 ◽

Vol 36 (1) ◽

pp. 396-397

Author(s):

E. Ruedl ◽

P. Schiller

Keyword(s):

Fusion Reactor ◽

Matrix Material ◽

Fusion Reactors ◽

First Wall ◽

Potential Matrix ◽

In Situ Deformation ◽

Α Particles ◽

Metal Aluminium

The low Z metal aluminium is a potential matrix material for the first wall in fusion reactors. A drawback in the application of A1 is the rel= atively high amount of He produced in it under fusion reactor conditions. Knowledge about the behaviour of He during irradiation and deformation in Al, especially near the surface, is therefore important.Using the TEM we have studied Al disks of 3 mm diameter and 0.2 mm thickness, which were perforated at the centre by double jet polishing. These disks were bombarded at∽200°C to various doses with α-particles, impinging at any angle and energy up to 1.5 MeV at both surfaces. The details of the irradiations are described in Ref.1. Subsequent observation indicated that in such specimens uniformly distributed He-bubbles are formed near the surface in a layer several μm thick (Fig.1).After bombardment the disks were deformed at 20°C during observation by means of a tensile device in a Philips EM 300 microscope.

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Dynamics of overdense plasma interacting with ultrashort intense laser and consideration on neutron yield

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:2006133106 ◽

2006 ◽

Vol 133 ◽

pp. 515-519

Author(s):

Y. Rhee ◽

S. M. Nam ◽

J. M. Han ◽

Y. H. Cha ◽

D. H. Kwon ◽

...

Keyword(s):

Neutron Yield ◽

Intense Laser ◽

Overdense Plasma

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Formation of α clusters in dilute neutron-rich matter

Science ◽

10.1126/science.abe4688 ◽

2021 ◽

Vol 371 (6526) ◽

pp. 260-264 ◽

Cited By ~ 1

Author(s):

Junki Tanaka ◽

Zaihong Yang ◽

Stefan Typel ◽

Satoshi Adachi ◽

Shiwei Bai ◽

...

Keyword(s):

Cross Sections ◽

Cluster Formation ◽

Reaction Cross ◽

Skin Thickness ◽

Neutron Skin ◽

Heavy Nuclei ◽

Α Decay ◽

Neutron Skin Thickness ◽

Reaction Cross Sections ◽

Α Particles

The surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster–knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between α-cluster formation and the neutron skin. This result, in turn, calls for a revision of the correlation between the neutron-skin thickness and the density dependence of the symmetry energy, which is essential for understanding neutron stars. Our result also provides a natural explanation for the origin of α particles in α decay.

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