
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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Ambient-temperature liquid jet targets for high-repetition-rate HED discovery science
PHYSICS OF PLASMAS
2022; 29 (12)
View details for DOI 10.1063/5.0097857
View details for Web of Science ID 000899004900003
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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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Versatile tape-drive target for high-repetition-rate laser-driven proton acceleration
HIGH POWER LASER SCIENCE AND ENGINEERING
2023; 11
View details for DOI 10.1017/hpl.2023.27
View details for Web of Science ID 000975396100001
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Diamond formation kinetics in shock-compressed C─H─O samples recorded by small-angle x-ray scattering and x-ray diffraction.
Science advances
2022; 8 (35): eabo0617
Abstract
Extreme conditions inside ice giants such as Uranus and Neptune can result in peculiar chemistry and structural transitions, e.g., the precipitation of diamonds or superionic water, as so far experimentally observed only for pure C─H and H2O systems, respectively. Here, we investigate a stoichiometric mixture of C and H2O by shock-compressing polyethylene terephthalate (PET) plastics and performing in situ x-ray probing. We observe diamond formation at pressures between 72 ± 7 and 125 ± 13 GPa at temperatures ranging from ~3500 to ~6000 K. Combining x-ray diffraction and small-angle x-ray scattering, we access the kinetics of this exotic reaction. The observed demixing of C and H2O suggests that diamond precipitation inside the ice giants is enhanced by oxygen, which can lead to isolated water and thus the formation of superionic structures relevant to the planets' magnetic fields. Moreover, our measurements indicate a way of producing nanodiamonds by simple laser-driven shock compression of cheap PET plastics.
View details for DOI 10.1126/sciadv.abo0617
View details for PubMedID 36054354
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High-repetition-rate, multi-MeV deuteron acceleration from converging heavy water microjets at laser intensities of 10(21) W/cm(2)
APPLIED PHYSICS LETTERS
2022; 121 (7)
View details for DOI 10.1063/5.0098973
View details for Web of Science ID 000861138400019
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Investigation of hard x-ray emissions from terawatt laser-irradiated foils at the Matter in Extreme Conditions instrument of the Linac Coherent Light Source
JOURNAL OF INSTRUMENTATION
2022; 17 (4)
View details for DOI 10.1088/1748-0221/17/04/T04004
View details for Web of Science ID 000819866900015
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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