Alpha particles from the photodisintegration of 9Be in the photon energy region 18 to 26 MeV

1978 ◽  
Vol 56 (1) ◽  
pp. 47-51 ◽  
Author(s):  
A. Buchnea ◽  
R. G. Johnson ◽  
K. G. McNeill
Keyword(s):  
Cross Section ◽  
Photon Energy ◽  
Energy Region ◽  
Alpha Particles ◽  
Upper Limit ◽  
Major Reaction ◽  
Reaction Channels ◽  
Integrated Cross Section

Alpha particles from the 9Be(γ,n)8Be(16.6) and 9Be(γ,α0)5He reactions were studied in the photon energy region 18 to 26 MeV; the results yielded a combined integrated cross section of 13.1 ± 2 MeV mb and an upper limit on the integrated (γ,α0) cross section of 4.0 MeV mb. This agrees within error with the integrated cross section of Becchi, Meneghetti, Sanzone, and Vitale, 10 ± 2 MeV mb, which would contain about 50% of any contribution from the (γ,α0) reaction. These reactions together with the 9Be(γ,n1)8Be reaction (which has an integrated cross section of 2.4 ± 0.4 MeV mb) are the major reaction channels contributing to the total photoneutron cross section in this energy region. Their sum, 15.5 MeV mb, agrees well with the results of Nathans and Halpern and Hughes, Sambell, Muirhead, and Spicer but disagrees with that of Costa, Pasqualini, Piragino, and Roasio.

Angular distributions and cross sections of the photoneutron reaction in 9Be in the photon energy region 18–26 MeV

1977 ◽  
Vol 55 (4) ◽  
pp. 364-369 ◽  
Author(s):  
A. Buchnea ◽  
R. G. Johnson ◽  
K. G. McNeill
Keyword(s):  
Cross Section ◽  
Photon Energy ◽  
Cross Sections ◽  
Energy Region ◽  
Angular Distributions ◽  
Photoneutron Reaction ◽  
Integrated Cross Section

The 9Be(γ,n0)8Be and 9Be(γ,n1)8Be reactions were studied in the photon energy region 18 to 26 MeV. The integrated cross section of the (γ,n0) reaction was found to be less than 0.1 MeV mb in this energy region. The integrated cross section for the (γ,n1) reaction in the energy region is 2.4 ± 0.4 MeV mb, which is 10 to 15% of the total photoneutron cross section. The measured angular distributions for the (γ,n1) reaction are consistent with the population of 3/2+ and 5/2+ states of 9Be. These results are consistent with slightly re-interpreted predictions of Majling, Kukulin, and Smirnov.

scholarly journals Direction-sensitive dark matter search with a low-background gaseous detector NEWAGE-0.3b”

2021 ◽  
Author(s):  
Tomonori Ikeda ◽  
Kiseki Nakamura ◽  
Takuya Shimada ◽  
Ryota Yakabe ◽  
Takashi Hashimoto ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cross Section ◽  
Confidence Level ◽  
Energy Region ◽  
Time Projection Chamber ◽  
Emission Rate ◽  
Dark Matter Search ◽  
Low Background ◽  
Upper Limit ◽  
Time Projection

Abstract NEWAGE is a direction-sensitive dark matter search using a low-pressure gaseous time projection chamber. A low alpha-ray emission rate micro pixel chamber had been developed in order to reduce background for dark matter search. We conducted the dark matter search at the Kamioka Observatory in 2018. The total live time was 107.6 days corresponding to an exposure of 1.1 kg⋅days. Two events remained in the energy region of 50-60 keV which was consistent with 2.5 events of the expected background. A directional analysis was carried out and no significant forward-backward asymmetry derived from the WIMP-nucleus elastic scatterings was found. Thus a 90% confidence level upper limit on Spin-Dependent WIMP-proton cross section of 50 pb for a WIMP mass of 100 GeV/c2 was derived. This limit is the most stringent yet obtained from direction-sensitive dark matter search experiments.

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.

An upper limit to the cross section for the reaction at SPS energies

1979 ◽  
Vol 84 (3) ◽  
pp. 354-356 ◽  
Author(s):  
D. Bertrand ◽  
G. Bertrand-Coremans ◽  
R. Blaes ◽  
F.W. Bullock ◽  
M. Dewit ◽  
...  
Keyword(s):  
Cross Section ◽  
Upper Limit ◽  
The Cross

Evidence for the Photoemission Nature of Gd 4f Resonant Photoemission

1998 ◽  
Vol 524 ◽  
Author(s):  
S. R. Mishra ◽  
T. R. Cummins ◽  
W. J. Gammon ◽  
G. D. Waddill ◽  
G. Van der-Laan ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Photon Energy ◽  
Photoelectron Spectroscopy ◽  
Emission Cross Section ◽  
Linear Dichroism ◽  
Constructive Interference ◽  
Resonant Photoemission ◽  
Magnetic Linear Dichroism ◽  
Spectroscopy Experiment

ABSTRACTThe constructive interference between direct and indirect channels above the absorption threshold of a core level leads to a massive increase in the emission cross section leading to a phenomenon called “resonant photoemission”. Using novel magnetic linear dichroism in angular distribution photoelectron spectroscopy experiment we have tried to understand the nature of the resonant photoemission process in Gd metal. The presence of dichroism in Gd 4f photoemission intensity at a photon energy corresponding to resonant photoemission clearly demonstrates the photoemission-like nature of the resonant photoemission process.

Dependence of the optical cross section of interface states on the photon energy at Si-SiO2 structures

1986 ◽  
Vol 168 (1-3) ◽  
pp. 665-671 ◽  
Author(s):  
A. Herms ◽  
J.R. Morante ◽  
J. Samitier ◽  
A. Cornet ◽  
P. Cartujo ◽  
...  
Keyword(s):  
Cross Section ◽  
Photon Energy ◽  
Interface States ◽  
Optical Cross Section

Experiments on the reaction T( d , n ) 4 He I. The 90° cross-section

1951 ◽  
Vol 204 (1079) ◽  
pp. 488-499 ◽  
Keyword(s):  
Cross Section ◽  
Heavy Water ◽  
Incident Beam ◽  
Absolute Magnitude ◽  
Alpha Particles ◽  
Low Energy ◽  
Energy Relation ◽  
Conventional Theory ◽  
Simultaneous Observation ◽  
The Cross

The 90° cross-section of the reaction 3 1 H( d , n ) 4 2 He has been investigated over the energy range 100 to 200 keV (energy of bombarding triton) using the 200 keV accelerating set of the establishment. Two methods have been used. As a preliminary experiment the yield of alpha-particles from a thick heavy-ice target was measured per unit charge of incident beam, as a function of deuteron energy, and the variation of cross-section deduced from the gradient of this excitation curve and the range energy relation for tritons in heavy water. Secondly, a comparison was made between the yield of alpha-particles from the D-T reaction and the yield of protons from the D-D reaction when a beam containing both deuterons and tritons was passed through a heavy-water vapour target. (The energy loss in this target was calculated as only a few hundred electron volts.) To do this a simultaneous observation was made of the protons and alpha-particles using the same counter. The values obtained for the cross-section have been compared with the resonance formulae given by Bretscher & French (1949) and by Tascbek, Everhart, Gittings, Hemmendinger & Jarvis (1948) and have been found to be in disagreement with formulae of this type. From considerations of the absolute magnitude of the cross-section it has been deduced that no conventional theory postulating reaction at a distance equal to the sum of the nuclear radii (cf. Konopinski & Teller 1948) will be able to explain this reaction. The evidence for a low-energy resonance (Allan & Poole 1949) is thought to be inconclusive.

Photoionization cross section of the O2+ (B2 Σg−) state in the energy region of 20.3–23.8 eV

1987 ◽  
Vol 135 (1-2) ◽  
pp. 51-56 ◽  
Author(s):  
Masatoshi Ukai ◽  
Atsushi Kimura ◽  
Shin Arai ◽  
Pascal Lablanquie ◽  
Kenji Ito ◽  
...  
Keyword(s):  
Cross Section ◽  
Energy Region ◽  
Photoionization Cross Section
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