Spectral Broadening of Characteristicγ-Ray Emission Peaks fromC12(He3

Abstract

The spectral broadening of characteristic γ-ray emission peaks from the reaction (12)C((3)He,pγ)(14)N was measured in D((3)He) plasmas of the JET tokamak with ion cyclotron resonance heating tuned to the fundamental harmonic of (3)He. Intensities and detailed spectral shapes of γ-ray emission peaks were successfully reproduced using a physics model combining the kinetics of the reacting ions with a detailed description of the nuclear reaction differential cross sections for populating the L1-L8 (14)N excitation levels yielding the observed γ-ray emission. The results provide a paradigm, which leverages knowledge from areas of physics outside traditional plasma physics, for the development of nuclear radiation based methods for understanding and controlling fusion burning plasmas.

Gamma-ray spectroscopy measurements of confined fast ions on ASDEX Upgrade

“…This can be ascribed to the contribution from proton capture on boron. A more clear manifestation of -ray emission from fast protons was provided by the observation of the E  =5.5 MeV peak due to the d(p,) 3 He reaction (figure 3). The peak stands out of the background level in a statistically meaningful way.…”

“…The peak stands out of the background level in a statistically meaningful way. Figure 4 (a) shows the measured d(p,) 3 He emission peak. Superimposed to the data is a simulated spectral shape obtained by adding a constant background to the result of a Monte Carlo simulation using the MCNP code (providing the spectrum of energies deposited in the detection crystal) folded with the instrumental energy resolution W  and the expected kinetic broadening W K that results from the relative ion motion as predicted in reference [14] and first observed in reference [15] (see below).…”

“…Deuterium is the major constituent of the bulk plasma. The expected -ray peak energies are E  =5.5 MeV for the d(p,) 3 He reactions and 9 MeV<E  <12 MeV for reactions with boron as target.…”

“…In JET, ions in the MeV range produced by Ion Cyclotron Resonance Heating (ICRH) are well confined thanks to the large plasma size and high plasma currents. The recent installation of high resolution spectrometers has enhanced the quality of the -ray emission measurements and contributed to the development of nuclear physics based methods and models for the understanding of plasma physics [3,4]. ASDEX Upgrade (AUG) [5] is somewhat smaller than JET in terms of plasma volume and current; however it is well equipped with fast ion diagnostics.…”

Response of LaBr3(Ce) scintillators to 2.5 MeV fusion neutrons

“…Gamma-ray emission results from interactions between the energetic ions and impurities that are naturally found in the plasma [2][3][4]. Recently, γ-ray measurements at low counting rates and high energy resolution in present tokamak devices [5,6] have shown that added parameters of the fast ion energy distribution can be obtained by combining information on the intensity and shape of characteristic peaks of γ-ray reactions occurring in the plasma [7][8][9][10]. A review on neutron and gamma-ray measurements in tokamak plasmas for fast ion studies has been recently published in [3].…”