A Helium Gas-Scintillator Active Target for Photoreaction Measurements

• Main Authors: Jebali, R. Al, Annand, J. R. M, Adler, J. -O, Akkurt, I, Buchanan, E, Brudvik, J, Fissum, K, Gardner, S, Hamilton, D. J, Hansen, K, Isaksson, L, Livingston, K, Lundin, M, McGeorge, J. C, MacGregor, I. J. D, MacRae, R, Middleton, D. G, Reiter, A. J. H, Rosner, G, Schröder, B, Sjögren, J, Sokhan, D, Strandberg, B
• Format: Journal Article
• Language: English
• Published: 18.03.2015
• Subjects: Physics - Instrumentation and Detectors; Physics - Nuclear Experiment
• DOI: 10.48550/arxiv.1503.05545

A multi-cell He gas-scintillator active target, designed for the measurement of photoreaction cross sections, is described. The target has four main chambers, giving an overall thickness of 0.103 $\mathrm{g/cm^{2}}$ at an operating pressure of 2 MPa. Scintillations are read out by photomultiplier tubes and the addition of small amounts of $\mathrm{N}_{2}$ to the He, to shift the scintillation emission from UV to visible, is discussed. First results of measurements at the MAX IV Laboratory tagged-photon facility show that the target has good timing resolution and can cope well with a high-flux photon beam. The determination of reaction cross sections from target yields relies on a Monte Carlo simulation, which considers scintillation light transport, photodisintegration processes in $^{4}\mathrm{He}$, background photon interactions in target windows and interactions of the reaction-product particles in the gas and target container. The predictions of this simulation are compared to the measured target response.