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Open AccessArticle

Active Oxygen Target for Studies in Nuclear Astrophysics with Laser Compton Backscattered γ-ray Beams

A.I. Alikhanyan National Science Laboratory, 2 Alikhanyan Bros. Str., Yerevan 0036, Armenia
School of Physics & Astronomy, University of Glasgow, Scotland G128QQ, UK
ELI-NP, Horia-Hulubay National Institute of Physics and Nuclear Engineering, Bucharest 077125, Magurele, Romania
Department Science and Technology, North Carolina Central University, Durham 27707, NC, USA
Author to whom correspondence should be addressed.
Particles 2018, 1(1), 126-137;
Received: 30 January 2018 / Revised: 16 May 2018 / Accepted: 16 May 2018 / Published: 20 May 2018
PDF [5024 KB, uploaded 20 July 2018]


An active target is being developed to be used in low-energy nuclear astrophysics experiments. It is a position- and time-sensitive detector system based on the low-pressure Multi Wire Proportional Chamber (MWPC) technique. Methylal ((OCH3)2CH2), at a pressure of a few Torr, serves as the working gas for MWPC operation, and in addition, the oxygen atoms of the methylal molecules serve as an experimental target. The main advantage of this new target detector system is that it has high sensitivity to the low-energy, highly-ionizing particles produced after photodisintegration of 16O and insensitivity to γ-rays and minimum ionizing particles. This allows users to detect only the products of the nuclear reaction of interest. The threshold energies for detection of α particles and 12C nuclei are about 50 keV and 100 keV, respectively. The main disadvantage of this detector is the small target thickness, which is around a few tens of μg/cm2. However, reasonable luminosity can be achieved by using a multimodule detector system and an intense, Laser Compton Backscattered (LCB) γ-ray beam. This paper summarizes the architecture of the active target and reports test results of the prototype detector. The tests investigated the timing and position resolutions of 30 × 30 mm2 low-pressure MWPC units using an α-particle source. The possibility of measuring the 16O(γ, α)12C cross-section in the 8–10 MeV energy region by using a LCB γ-ray beam is also discussed. A measurement of the 16O(γ, α)12C cross-section will enable the reaction rate of 12C(α, γ)16O to be determined with significantly improved precision compared to previous experiments. View Full-Text
Keywords: nuclear astrophysics; active target; gaseous detectors nuclear astrophysics; active target; gaseous detectors

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Ajvazyan, R.; Annand, J.R.M.; Balabanski, D.L.; Grigoryan, N.; Kakoyan, V.; Khachatryan, P.; Khachatryan, V.; Livingston, K.; Montgomery, R.; Vardanyan, H.; Vlahovic, B.; Zhamkochyan, S.; Margaryan, A. Active Oxygen Target for Studies in Nuclear Astrophysics with Laser Compton Backscattered γ-ray Beams. Particles 2018, 1, 126-137.

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