
Griffin Glenn
Ph.D. Student in Applied Physics, admitted Autumn 2019
Bio
I am a PhD student in the Stanford Department of Applied Physics. My research, conducted in the SLAC National Accelerator Laboratory High Energy Density Science Division, focuses on developing sources of laser-driven ion and neutron beams using cryogenic liquid jet targets developed by our group.
Honors & Awards
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DOE NNSA Stewardship Science Graduate Fellowship, US DOE National Nuclear Security Administration (2020-2024)
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NSF Graduate Research Fellowship, National Science Foundation (2019-2020)
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Dean's Honored Graduate, College of Natural Sciences, The University of Texas at Austin (2019)
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Highest Academic Achievement Award, Department of Physics, The University of Texas at Austin (2019)
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Mitchell Award for Undergraduate Academic Excellence, University Co-op, The University of Texas at Austin (2019)
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Barry Goldwater Scholarship, Barry Goldwater Scholarship and Excellence in Education Foundation (2018)
Education & Certifications
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BS, The University of Texas at Austin, Physics Honors (2019)
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BA, The University of Texas at Austin, Plan II Honors (2019)
All Publications
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Improved large-energy-range magnetic electron-positron spectrometer for experiments with the Texas Petawatt Laser
JOURNAL OF INSTRUMENTATION
2019; 14
View details for DOI 10.1088/1748-0221/14/03/P03012
View details for Web of Science ID 000460721500009
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2D monochromatic x-ray imaging for beam monitoring of an x-ray free electron laser and a high-power femtosecond laser
REVIEW OF SCIENTIFIC INSTRUMENTS
2021; 92 (1): 013510
Abstract
In pump-probe experiments with an X-ray Free Electron Laser (XFEL) and a high-power optical laser, spatial overlap of the two beams must be ensured to probe a pumped area with the x-ray beam. A beam monitoring diagnostic is particularly important in short-pulse laser experiments where a tightly focused beam is required to achieve a relativistic laser intensity for generation of energetic particles. Here, we report the demonstration of on-shot beam pointing measurements of an XFEL and a terawatt class femtosecond laser using 2D monochromatic Kα imaging at the Matter in Extreme Conditions end-station of the Linac Coherent Light Source. A thin solid titanium foil was irradiated by a 25-TW laser for fast electron isochoric heating, while a 7.0 keV XFEL beam was used to probe the laser-heated region. Using a spherical crystal imager (SCI), the beam overlap was examined by measuring 4.51 keV Kα x rays produced by laser-accelerated fast electrons and the x-ray beam. Measurements were made for XFEL-only at various focus lens positions, laser-only, and two-beam shots. Successful beam overlapping was observed on ∼58% of all two-beam shots for 10 μm thick samples. It is found that large spatial offsets of laser-induced Kα spots are attributed to imprecise target positioning rather than shot-to-shot laser pointing variations. By applying the Kα measurements to x-ray Thomson scattering measurements, we found an optimum x-ray beam spot size that maximizes scattering signals. Monochromatic x-ray imaging with the SCI could be used as an on-shot beam pointing monitor for XFEL-laser or multiple short-pulse laser experiments.
View details for DOI 10.1063/5.0014329
View details for Web of Science ID 000630907400004
View details for PubMedID 33514225
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Optimization of radiochromic film stacks to diagnose high-flux laser-accelerated proton beams
REVIEW OF SCIENTIFIC INSTRUMENTS
2020; 91 (9): 093303
Abstract
Here, we extend flatbed scanner calibrations of GafChromic EBT3, MD-V3, and HD-V2 radiochromic films using high-precision x-ray irradiation and monoenergetic proton bombardment. By computing a visibility parameter based on fractional errors, optimal dose ranges and transitions between film types are identified. The visibility analysis is used to design an ideal radiochromic film stack for the proton energy spectrum expected from the interaction of a petawatt laser with a cryogenic hydrogen jet target.
View details for DOI 10.1063/5.0020568
View details for Web of Science ID 000573944100003
View details for PubMedID 33003776
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Beam distortion effects upon focusing an ultrashort petawatt laser pulse to greater than 10(22) W/cm(2)
OPTICS LETTERS
2019; 44 (11): 2764–67
View details for DOI 10.1364/OL.44.002764
View details for Web of Science ID 000469838100039