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Chemically-polarized material for nuclear and particle physics

Benjamin G. Collins, Daniel P. Watts, Mikhail Bashkanov, Stephen Kay, Simon B. Duckett, Andreas Thomas, Dmitry Budker, Danila Barskiy, Raphael Kircher

Abstract

Spin-polarized solid targets have underpinned many recent key advances in nuclear and particle physics, yet traditional methods to produce them face significant limitations due to the high cost and demanding cryogenic and magnetic field requirements. These factors constrain experimental geometries and present challenges in intense radiation environments where depolarization and materials damage can occur. We present the first results assessing the capabilities of the chemical hyperpolarization (ChHP) method Signal Amplification By Reversible Exchange (SABRE) to act as the polarization method to produce targets or active detector media. We show by using in-beam measurements that there is no depolarizing effect observed with the SABRE-polarized material in the A2 photon beam at the Mainzer Mikrotron (MAMI), as well as showing the resilience of such media to radioactive doses of up to \SI{3}{\kilo\gray}. We also illustrate the capabilities for using SABRE-polarized material as a scintillation or Cherenkov detector.

Chemically-polarized material for nuclear and particle physics

Abstract

Spin-polarized solid targets have underpinned many recent key advances in nuclear and particle physics, yet traditional methods to produce them face significant limitations due to the high cost and demanding cryogenic and magnetic field requirements. These factors constrain experimental geometries and present challenges in intense radiation environments where depolarization and materials damage can occur. We present the first results assessing the capabilities of the chemical hyperpolarization (ChHP) method Signal Amplification By Reversible Exchange (SABRE) to act as the polarization method to produce targets or active detector media. We show by using in-beam measurements that there is no depolarizing effect observed with the SABRE-polarized material in the A2 photon beam at the Mainzer Mikrotron (MAMI), as well as showing the resilience of such media to radioactive doses of up to \SI{3}{\kilo\gray}. We also illustrate the capabilities for using SABRE-polarized material as a scintillation or Cherenkov detector.
Paper Structure (7 sections, 2 equations, 8 figures, 3 tables)

This paper contains 7 sections, 2 equations, 8 figures, 3 tables.

Table of Contents

  1. Introduction
  2. Methodology
  3. Results
  4. In-beam polarization decay
  5. High dose sample irradiation
  6. Fluorescence measurements
  7. Conclusions

Figures (8)

  • Figure 1: a) Spin-order transfer during SABRE, converting p-H_2 to o-H_2 and an initially unpolarized spin to a polarized spin. The active SABRE catalyst shown here is of the form [IrCl(H)_2(NHC)(S)_2], where S is a bound substrate molecule and NHC = N-heterocyclic carbene. b) Substrates investigated in this study.
  • Figure 2: Diagram of the experimental procedure. a) Prepare sample and fill with p-H_2. b) Transfer to Halbach array and shake for 45s. c) Transfer to MRI system and start acquisition. d) Vacate hall and turn on photon beam.
  • Figure 3: a) MRI system positioning next to the beamline. Here the end of the beamline and the MRI system are separated by approximately 50 cm. b) The polarization cell. c) Close-up of the glass insert in the polarization cell.
  • Figure 4: Diagram showing the placement of the cell within the MRI system and in relation to the beam. The black dotted lines show the internal bore of the MRI system, the red dotted line shows the path of the beam, and the solid red lines show the sensitive region of the MRI system.
  • Figure 5: Normalized polarization decay profiles for a) 3,5-dcpy, b) 3,5-dbpy, c) 2,6-dcpz. The dotted lines indicate the start time of the photon beam.
  • ...and 3 more figures