John W. Mitchell

Astrophysics Science Division
NASA/GSFC
Code 661, Astroparticle Physics Laboratory
Greenbelt, MD 20771

tel: 301-286-3199
fax: 301-286-1682
e-mail: John.W.Mitchell @ nasa.gov

Present Position

Astrophysicist, High Energy Cosmic Ray Group

Brief Bio

Following graduate work in low-temperature solid-state physics at Louisiana State University, I joined the LSU Particle Astrophysics Group in 1985, working on accelerator, balloon, and satellite projects. I carried out a series of measurements of nuclear reaction cross-sections at typical cosmic-ray energies at the LBNL Bevatron accelerator and developed a dedicated Monte-Carlo program to model fragmentation in nuclear collisions. I designed and built the time-of-flight system for the SMILI balloon-borne cosmic-ray instrument and analyzed trapped particle data from the Phoenix-I satellite.

I moved to the GSFC High Energy Cosmic Ray Group in 1990, working on a wide variety of balloon instruments as well as on the development of satellite instruments and instrument concepts. I was the Instrument Scientist/Manager for IMAX and ISOMAX and was responsible for overall instrument design. I designed and built high-performance time-of-flight, Cherenkov detector, and trigger systems for several cosmic ray instruments (MASS2, TS93, CAPRICE, IMAX, ISOMAX, BESS-Polar). Presently I am the US Spokesperson and NASA PI for the BESS-Polar program and the NASA PI for the new PoGO instrument. I am the US Lead for the PAMELA satellite instrument and have played major roles in instrument concept development for the ACCESS and OWL missions. I lead the ACCESS test program at the CERN Super Proton Synchrotron accelerator.

I have continued to pursue a program of high-energy nuclear and particle physics measurements. In addition to nuclear and particle cross-section measurements, I have conducted searches for rare, short-lived particles. My accelerator work is now focused on the STAR experiment at the Brookhaven Relativistic Heavy-Ion Collider (RHIC) to investigate matter at extreme nuclear temperatures. I have designed and built trigger and detector systems for BNL experiments E866, E878, E896, and STAR and LBNL experiments E683H, E849H, E859H, and E938H.

Educational Background

PhD (Physics) 1985, Louisiana State University, "Surface Landau-Level Resonance in Silver"
MS (Physics) 1975, Louisiana State University
MA (Mathematics) 1973, Northern Michigan University
BS (Physics Summa Cum Laude) 1972, Northern Michigan University

Fulbright Foundation Short Term Scientific Mission 1986 (France-Physics of New Materials).
Fifth International School of Cosmic Ray Astrophysics 1986

Research Interests

Experimental Particle Astrophysics
Gamma-ray Polarimetry
Experimental Nuclear Physics
Experimental Particle physics
Particle detector development
Gamma-ray detector development

Current Projects

Principal Investigator, BESS-Polar (Balloon-borne Experiment with a Superconducting Spectrometer - Polar) long-duration balloon (LDB) cosmic ray spectrometer to measure cosmic-ray particles and antiparticles with a focus on searching for exotic sources of cosmic antiprotons. First Antarctic flight December 2004. Preparing for second flight December 2007.

Principal Investigator, PoGO (Polarized Gamma-ray Observer) a new balloon-borne instrument to measure phase-resolved polarization of gamma radiation (25 keV - 200 keV) from e.g. synchrotron radiation, compton scattering, or strong magnetic fields in astrophysical objects. First flight planned September 2008

US Lead: PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) cosmic-ray satellite instrument to measure cosmic-ray particles and antiparticles. Launch planned for December 2005.

Co-Investigator: TIGER (Trans-Iron Galactic Element Recorder) LDB cosmic-ray composition instrument to investigate origin of ultraheavy nuclei. Antarctic flights in 2001 and 2003.

Co-Investigator: NIGHTGLOW balloon-borne instrument to measure the near UV airglow.

Co-Investigator: CREAM (Cosmic-ray Energetics and Mass) LDB/ULDB instrument to measure very-high energy cosmic-ray spectra. First Antarctic flight 2004.

Accelerator Test Lead/Co-Investigator: ACCESS (Advanced Cosmic-ray Composition Experiment for Space Science) satellite mission to measure cosmic-ray spectra near the supernova acceleration limit.

Co-Investigator: ENTICE (Energetic Trans-Iron Composition Experiment) cosmic-ray composition satellite instrument to investigate origin of ultraheavy nuclei.

Co-Investigator: OWL (Orbiting Wide-angle Light Collectors) satellite mission to measure ultra-high-energy cosmic particles.

Co-Investigator: STAR (Solenoidal Tracker at RHIC) accelerator experiment at the Relativistic Heavy-Ion Collider to investigate matter at extreme nuclear temperature.

Selected Publications

Selected from 163 refereed publications.

2005 “Experimental and theoretical challenges in the search for the quark-gluon plasma: The STAR Collaboration's critical assessment of the evidence from RHIC collisions,” J. Adams, et al., Nucl. Phys. A757 (1-2) 102.

2005 “Search for Cosmic-Ray Antideuterons,” H. Fuke, et al., Phys. Rev. Letters 95 (8) id. 081101.

2005 “Beam test of a prototype detector array for the PoGO astronomical hard X-ray/soft gamma-ray polarimeter,” T. Mizuno, et al., Nucl. Inst. and Methods A540 (1) 158.

2005 “NIGHTGLOW: an instrument to measure the Earth’s nighttime ultraviolet glow—results from the first engineering flight,” LM Barbier, et al., Astropart. Phys. 22 (5-6) 439.

2005 “Precise Measurements of the Cosmic Ray Antiproton Spectrum with BESS Including the Effects of Solar Modulation,” JW Mitchell, et al., Adv. Space Res. 35 (1) 135.

2004 “The time-of-flight system of the PAMELA experiment on satellite,” G. Osteria, et al., Nucl. Inst. and Methods A535 (1-2) 152.

2004 “Observing the Ultrahigh Energy Universe with OWL Eyes,” FW Stecker, et al., Nucl. Phys. B136, 433.

2004 “Rapidity and centrality dependence of proton and antiproton production from 197Au + 197Au collisions at √(SNN )=130 GeV,” J Adams, et al., Phys. Rev. C70 (4) id. 041901.

2004 “The BESS Program,” JW Mitchell, et al., Nucl. Phys. B Proc. Sup. 134, 31.

2004 “Abundance of the Radioactive 10Be and Other Light Isotopes in the Cosmic Radiation up to 2 GeV per Nucleon with the Balloon-Borne Instrument ISOMAX,” T Hams, et al., Astrpphys. J. 611 (2) 892.

2004 “Measurements of primary and atomospheric cosmic-ray spectra with the BESS-TeV spectrometer,” S Haino, et al., Phys. Letters B594 (1-2) 35.

2004: “BESS-polar experiment,” T Yoshida ,et al., Adv. Space Res. 33 (10)1755.

2004 ‘Measurements of Compton scattered transition radiation at high Lorentz factors,” GL Case, et al., Nucl. Inst. and Meth A524 (1-3): 257.

2004 ‘The TOFp/pVPD time-of-flight system for STAR,” W Llope, F Geurts, JW Mitchell, et al., Nucl. Inst. and Meth. A522 (3): 252.

2004 “Progress of the BESS Superconducting Spectrometer,” S Haino, et al., Nucl. Inst. and Meth A518 (1-2): 167.

2003 “The cosmic-ray proton and helium spectra measured with the CAPRICE98 balloon experiment,” M Boezio et al., Astroparticle Phys. 19, 583.

2003 “Measurements of proton, helium and muon spectra at small atmospheric depths with the BESS spectrometer,” K Abe et al., Physics. Letters B564, 8.

2002 “BESS-Polar: Long duration flights at Antarctica to search for primordial antiparticles ,” A Yamamoto et al., Nucl. Phys. B – Proc. Supp. 113, 208.

2002 “Measurements of the absolute energy spectra of cosmic-ray positrons and electrons above 7 GeV,” C Grimani et al., Astro. & Astrophys. 392, 287.

2002 “Distributed drift chamber design for rare particle detection in relativistic heavy ion collisions,” R Bellwied et al., NIM A485, 371.

2002 "Measurements of cosmic-ray low-energy antiproton and proton spectra in a transient period of solar field reversal," Y Asaoka et al., 2002, Phys. Rev. Letters 88(5): art. no. 051101.

2002 "Measurement of cosmic-ray hydrogen and helium and their isotopic composition with the BESS experiment." JZ Wang et al., 2002, Ap. J. 564, 244.

2001 “Precise measurements of cosmic-ray hydrogen and helium spectra with BESS,” T. Sanuki et al., Adv. Space Res. 27, 761.

2001 “The cosmic-ray antiproton flux between 3 and 49 GeV,” M. Boezio et al., ApJ 561, 787.

2001 “Measurements of cosmic-ray electrons and positrons by the WiZard/CAPRICE collaboration,” M. Boezio et al., Adv. Space Res. 27, 669.

2000 "Precise measurement of cosmic-ray proton and helium spectra with the BESS spectrometer," T. Sanuki et al., Ap. J. 545, 1135.

2000 "ISOMAX: a balloon-borne instrument to measure cosmic ray isotopes," M Hof et al., NIM 454, 180.

2000 "Precision measurement of cosmic-ray antiproton spectrum," S Orito et al., Phys. Rev. Letters 84 (6), 1078.

2000 "The absolute flux of protons and helium at the top of the atmosphere using IMAX,"W Menn et al., Ap. J. 533, 281.

2000 "The cosmic-ray electron and positron spectra measured at 1 Au during solar minimum activity," M Boezio et al., Ap. J. 532, 653.

1999 "First results from the H-0 di-baryon search and hyperon production measurements by the AGS Experiment 896," H Caines et al., Nucl.. Phys. A661, 170C.

1999 "Strange and multi-strange baryon measurement in Au plus Au collisions at 11.6A(GeV/c) with the silicon drift detector array from the AGS experiment E896," G Lo Curto et al., Nucl. Phys. A 661, 489C.

1999 "Large-Area Scintillating-Fiber Time-of-Flight/Hodoscope Detectors for Particle Astrophysics Experiments," DJ Lawrence et al., Nucl. Inst. and Meth. A420, 402.

1998 "Measurement of Low-Energy Cosmic-Ray Antiprotons at Solar Minimum," H Matsunaga, et al., Phys. Rev. Letters 81, 4052.

1998 "Photodetectors for OWL", JW Mitchell, AIP Conference Proceedings 433, 500.

1998 "The Cosmic Ray 3He/4He Ratio from 200 MeV/nucleon to 3.7 GeV/nucleon," O Reimer, et al., Ap. J. 496, 490.

1997 "Antiproton distributions in Au+nucleus collisions," M Bennett, et al., Phys. Rev. C56, 1521.

1997 "A Heavy Ion Spectrometer System Used for the Measurement of Projectile Fragmentation of Relativistic Heavy Ions," S Albergo, et al., Radiat. Meas. 27, 549.

1997 "The cosmic ray antiproton flux between 0.62 and 3.19 GeV measured near solar minimum activity," M Boezio, et al., Ap.J. 487, 415.

1997 "Relativistic Interaction of 22Ne and 26Mg in Hydrogen and the Cosmic-Ray Oxygen Implications," C-X Chen, et al., Ap. J. 479, 504.

1997 "Cosmic-Ray Antiproton Flux in the Energy Range from 200 to 600 MeV," A Moiseev, et al., Ap. J. 474, 479.

1996 "Measurement of Cosmic Ray Antiprotons from 3.7 to 19 GeV", M Hof, et al., Ap. J. Letters 467, L33.

1996 "Measurement of 0.25 - 3.2 GeV Antiprotons in the Cosmic Radiation," JWMitchell, et al., Phys. Rev. Letters 76, 3057.

1995 "Observation of Cosmic-Ray Antiprotons at Energies below 500 MeV," K Yoshimura, et al., Phys. Rev. Letters 75, 3792.

1995 "Centrality Dependence of Antiproton Production in Au+Au Collisions," D Beavis, et al., Phys. Rev. Letters 75, 3633.

1995 "Search for New Meta-stable Particles Produced in Au+Au Collisions at 10.8 A GeV/c," D Beavis, et al., Phys. Rev. Letters 75, 3078.

1994 "Performance of Drift Chambers in a Magnetic Rigidity Spectrometer for Measuring the Cosmic Radiation," M Hof, et al., Nucl. Inst. and Meth. A 345, 561.

1993 "The Cosmic Ray 3He/4He Ratio from 100 MeV/amu to 1300 MeV/amu," JJ Beatty, et al., Ap. J. 413, 268.

1993 "Balloon Observations of Galactic Cosmic Ray Helium Before and During a Flare-Induced Forbush Decrease," J Clem, et al., Geophys. Res. Letters 20, 1743.

1989 "Low Altitude Trapped Protons at the Geomagnetic Equator," TG Guzik, MA Miah, JW Mitchell and JP Wefel, J Geophys. Res. 94, 145.

1985 "Electron-phonon Scattering in Silver: Surface Landau-level Resonances," JW.Mitchell and RG Goodrich, Phys. Rev. B32, 4977.

1985 "Fermi Velocities in Silver: Surface Landau-level Resonances," JW Mitchell and RG Goodrich, Phys. Rev. B32, 4969.