Low-energy cross sections for 10B(p, α) 7Be

doi:10.1016/0375-9474(72)91074-3

Nuclear Physics A

Volume 195, Issue 2, 13 November 1972, Pages 527-533

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Abstract

Cross sections were determined for the ¹⁰B(p, α)⁷Be reaction between 60 keV and ¹⁸⁰ keV proton energies using an activation method as well as direct α-detection by a solid-state track detector. In the energy region investigated the influence of the 8.694 MeV state of ¹¹C on S(E) has been observed. The cross section for the Gamow energy is given. The half-width of this level and the branching ratio ⁷Be(ɛ)⁷Li were found to be Γ ≈ 300 keV and R = 0.104±0.003, respectively.

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Cited by (28)

10Be low-energy AMS with the passive absorber technique
2019, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
Citation Excerpt :
The 10B(p,α)7Be nuclear reaction occurs between 10B and protons and results in α and 7Be particles. Its cross section increases with the projectiles energy in the range studied at the SARA facility [29–31], meaning that the probability for the 10B(p,α)7Be reaction to occur is maximal at the first SiN foil of the absorber, since the 10B ions have maximal energies when they hit it. For a 2.4 MeV 10B beam, the resulting α and 7Be have maximal energies of about 3.5 MeV as the reaction Q-value is 1.15 MeV [32].
The passive absorber technique is one of the most common ways to suppress the ¹⁰B interference during ¹⁰Be measurements at facilities working with beam energies above 7 MeV. At lower energies, the range straggling complicates the application of absorbers, so that other suppression techniques are normally preferred. Several experiments were conducted at the SARA (hosted at Centro Nacional de Aceleradores, Seville, Spain) and VERA (Faculty of Physics, University of Vienna, Austria) AMS facilities to demonstrate the potential of the passive absorber technique also at and below 2.4 MeV. Two different absorber setups were installed and tested. For the detection of the rare isotopes both facilities used a gas ionization chamber optimized for light ions detection based on the same design. The absorber installed at the SARA facility was a combination of SiN foils and an isobutane gas volume, whereas VERA was equipped with an absorber constituted of a stack of SiN foils. In both cases, ¹⁰Be could be clearly separated from ¹⁰B and the use of a passive absorber at the entrance of the detector gave higher transmission compared to the degrader method.
Depending on the absorber design, different background contributions could be identified: Rutherford scattering of ¹⁰B on the protons contained in the SiN foils and isobutane gas was responsible of a severe background at SARA, and fragments from ⁹Be¹H molecules surviving the stripping process resulted in events partially overlapping the ¹⁰Be gate at VERA. The measured transmissions and background levels will be presented for the tested setups, as well as the advantages and disadvantages of each absorber design.
10Be and 26Al low-energy AMS using He-stripping and background suppression via an absorber
2014, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
The transmission of the ion beam through a tandem accelerator is a critical parameter for efficient detection of long-lived radionuclides by sensitive accelerator mass spectrometry (AMS). With beam energies at the accelerator terminal of less than 600 keV, high transmissions are obtained using He as stripper gas. Here, we discuss Be, B, and Al transmissions in view of their application in the AMS determination of the long-lived radioisotopes ¹⁰Be and ²⁶Al with compact facilities. The charge state 2+ of Al and Be shows a high yield, but in both cases an intense background from other nuclides has to be handled. The applicability of a combination of an absorber cell with a gas ionization chamber was tested for suppression of the main background for ¹⁰Be²⁺ (¹⁰B²⁺) and ²⁶Al²⁺ (¹³C¹⁺). Energy loss simulations of the involved nuclides confirm the performance observed in the experiments. The findings concerning He stripping and detection methods at low energies may allow the construction of very compact AMS setups for light isotopes.
NACRE II: An update of the NACRE compilation of charged-particle-induced thermonuclear reaction rates for nuclei with mass number A > 16
2013, Nuclear Physics A
An update of the NACRE compilation [3] is presented. This new compilation, referred to as NACRE II, reports thermonuclear reaction rates for 34 charged-particle induced, two-body exoergic reactions on nuclides with mass number $A < 16$ , of which fifteen are particle-transfer reactions and the rest radiative capture reactions. When compared with NACRE, NACRE II features in particular (1) the addition to the experimental data collected in NACRE of those reported later, preferentially in the major journals of the field by early 2013, and (2) the adoption of potential models as the primary tool for extrapolation to very low energies of astrophysical S-factors, with a systematic evaluation of uncertainties.
As in NACRE, the rates are presented in tabular form for temperatures in the $10^{6} ≲ T ⩽ 10^{10} K$ range. Along with the ‘adopted’ rates, their low and high limits are provided. The new rates are available in electronic form as part of the Brussels Library (BRUSLIB) of nuclear data. The NACRE II rates also supersede the previous NACRE rates in the Nuclear Network Generator (NETGEN) for astrophysics. [http://www.astro.ulb.ac.be/databases.html]
A compilation of charged-particle induced thermonuclear reaction rates
1999, Nuclear Physics A
Low-energy cross section data for 86 charged-particle induced reactions involving light (1 ⩽ Z ⩽ 14), mostly stable, nuclei are compiled. The corresponding Maxwellian-averaged thermonuclear reaction rates of relevance in astrophysical plasmas at temperatures in the range from 10⁶ K to 10¹⁰ K are calculated. These evaluations assume either that the target nuclei are in their ground state, or that the target states are thermally populated following a Maxwell-Boltzmann distribution, except in some cases involving isomeric states.
Adopted values complemented with lower and upper limits of the rates are presented in tabular form. Analytical approximations to the adopted rates, as well as to the inverse/direct rate ratios, are provided.
The 10B(p, α<inf>0</inf>)7Be reaction in the thermonuclear energy region
1991, Nuclear Physics, Section A
Differential and total cross sections for the ¹⁰B(p, α₀)⁷Be reaction at proton energies between 120 and 480 keV have been measured. The total cross section shows a weak structure at E_p∼390keV. The S-factors agree with those of Szabo et al., but disagree with those of Burcham and Freeman by a factor of 1.3 The S-factors in this energy region are predominantly due to the tail of the 0.01 MeV resonance. The thermonuclear reaction rates show large discrepancies when compared with those of Caughlan et al. and Roughton et al.
Energy levels of light nuclei A = 11-12
1980, Nuclear Physics, Section A

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Nuclear Physics A

Abstract

Reference (9)

Nucl. Phys.

Phil. Mag.

Atomki Közl.

thesis

Cited by (28)

<sup>10</sup>Be low-energy AMS with the passive absorber technique

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NACRE II: An update of the NACRE compilation of charged-particle-induced thermonuclear reaction rates for nuclei with mass number A > 16

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The <sup>10</sup>B(p, α<inf>0</inf>)<sup>7</sup>Be reaction in the thermonuclear energy region

Energy levels of light nuclei A = 11-12