Gradient magnet design for simultaneous detection of electrons and positrons in the intermediate MeV range
Abstract
We report the design and development of a compact electron and positron spectrometer based on tapered neodymium iron boron magnets to characterize the pairs generated in laser-matter experiments. The tapered design forms a gradient magnetic field component allowing energy dependent focusing of the dispersed charged particles along a chosen detector plane. The mirror symmetric design allows for simultaneous detection of pairs with energies from 2 MeV to 500 MeV with an accuracy of ≤10% in the wide energy range from 5 to 110 MeV for a parallel beam incident on a circular aperture of 20 mm. The energy resolution drops to ≤20% for 4–90 MeV range for a divergent beam originating from a point source at 20 cm away (i.e., a solid angle of ∼8 milli steradians), with ≤10% accuracy still maintained in the narrower energy range from 10 to 55 MeV. It offers higher solid angle acceptance, even for the divergent beam, compared to the conventional pinhole aperture-based spectrometers. The proposed gradient magnet is suitable for the detection of low flux and/or monoenergetic type electron/positron beams with finite transverse sizes and offers unparalleled advantages for gamma-ray spectroscopy in the intermediate MeV range.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 01, 2019
- Source ID
- 10.1063/1.5099155
Entities
People
- Bjorn Manuel Hegelich
- E. Gaul
- Ganesh Tiwari
- Rotem Kupfer
- Xuanmao Jiao
Organizations
- Air Force Office of Scientific Research
- University of Texas at Austin