@article{weldon_mueller_awe_barbeau_hedges_li_mishra_mattingly_2020, title={Characterization of stilbene's scintillation anisotropy for recoil protons between 0.56 and 10 MeV}, volume={977}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2020.164178}, abstractNote={The scintillation anisotropy of the single-crystal organic scintillator trans-stilbene was characterized for recoil protons between 0.56 and 10 MeV. The light output and pulse shape anisotropies were measured at 11 distinct recoil proton energies for over 168 recoil proton trajectories relative to the crystal axes. The measurements were performed using a neutron scatter kinematic measurement system and quasi-monoenergetic neutron beams produced by the tandem Van de Graaff accelerator at Triangle Universities Nuclear Laboratory (TUNL). The extensive recoil proton directional coverage enables interpolation over both energy and direction to form a complete response function of stilbene’s scintillation anisotropy for the measured energy range.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Weldon, R. A., Jr. and Mueller, J. M. and Awe, C. and Barbeau, P. and Hedges, S. and Li, L. and Mishra, M. and Mattingly, J.}, year={2020}, month={Oct} } @article{weldon_mueller_mattingly_2020, title={Exploiting stilbene's scintillation anisotropy for neutron source localization}, volume={967}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2020.163834}, abstractNote={A technique for neutron source localization that exploits the scintillation anisotropy of stilbene is presented. The light output anisotropy of stilbene and constraints on the direction of recorded scatter events imposed by a threshold were used to estimate the direction of a 252Cf neutron source relative to the crystal axes of a stilbene crystal. The neutron source location was determined via triangulation using source directions estimated from multiple detectors. Two measurements that illustrate the efficacy of the technique are presented. The first measurement was designed with a favorable geometry for triangulation, which resulted in low uncertainties in the estimate of the neutron source location. The second measurement was designed with both favorable and unfavorable geometries for triangulation, which exhibited low and high uncertainties in the estimates of neutron source location, respectively. Pair-wise combinations of three detectors were used to estimate the source location for both measurements. The neutron source was localized with errors of 5.0, 8.9, and 3.9 cm for the first measurement with source detector-distance of 89, 90, and 88 cm for the three detectors. The neutron source was localized with errors of 2.8, 14.2, 6.2 cm for the second measurement with source detector-distances of 233, 123, and 130 cm.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Weldon, R. A., Jr. and Mueller, J. M. and Mattingly, J.}, year={2020}, month={Jul} } @article{weldon_mueller_barbeau_mattingly_2020, title={Measurement of EJ-228 plastic scintillator proton light output using a coincident neutron scatter technique}, volume={953}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2019.163192}, abstractNote={The light output function of the fast plastic scintillator EJ-228 was measured using a coincident neutron scatter measurement system and quasi-monoenergetic neutron beams produced by the tandem Van de Graaff accelerator at Triangle Universities Nuclear Laboratory. The measurement of scintillator light output using neutron scatter kinematics provides a model-independent determination of the light output function with quantifiable sources of uncertainty. Consequently, light output measurements performed using this method have a key advantage compared to other techniques: the characterization of the scintillating material depends only on the material itself and not on the size of the detector. This advantage is realized if the light output is defined as the absolute neutron light output relative to the absolute electron light output and two conditions are met: (1) the scintillator volume is fully illuminated and edge effects can be neglected during energy calibration measurements and light output measurements, and (2) the light attenuation length for scintillation photons in the material is long enough that the lowest energy interaction of interest produces a statistically significant number of scintillation photons for an interaction at any position in the scintillator volume. Commonly implemented measurement and analysis techniques for light output characterizations are explored and evidence of bias is provided for characterizations performed by analyzing the full-energy deposition edge of a light output spectrum.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Weldon, R. A., Jr. and Mueller, J. M. and Barbeau, P. and Mattingly, J.}, year={2020}, month={Feb} } @article{weldon_mueller_lynch_schuster_hedges_awe_li_barbeau_mattingly_2019, title={High-precision characterization of the neutron light output of stilbene along the directions of maximum and minimum response}, volume={927}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2018.10.075}, abstractNote={The scintillation light output response of stilbene crystals has been measured for protons recoiling along the a, b, and c’ crystalline axes with energies between 1.3 and 10 MeV using neutrons produced with the tandem Van de Graaff accelerator at Triangle Universities Nuclear Laboratory. The proton recoil energy and direction were measured using the coincident detection of neutrons between a stilbene scintillator and an array of EJ-309 liquid scintillators spanning arranged neutron recoil angles. The maximum light output was found to coincide with proton recoils along the a-axis, in disagreement with other published measurements, which reported the b-axis as the direction of the maximum light output. Additional measurements were conducted using two different stilbene crystals to confirm these results: a second measurement using the coincident detection of neutrons; measurements of neutron full energy deposition events along the a and b axes; and measurements of the count rate for 252Cf neutrons traveling along the a and b axes directions. All measurements found that recoils along the a-axis produce the maximum light output.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Weldon, R. A., Jr. and Mueller, J. M. and Lynch, C. and Schuster, P. and Hedges, S. and Awe, C. and Li, L. and Barbeau, P. and Mattingly, J.}, year={2019}, month={May}, pages={313–319} }