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Plasma Science and Fusion Center

Massachusetts Institute of Technology

 
 

Maria Gatu Johnson

Research Scientist

Maria Gatu Johnson

MIT Plasma Science & Fusion Center

Email: gatu@psfc.mit.edu

Phone: (617) 253-7024

Address: Room NW17-241

Related links: High-Energy-Density Physics Division

Biographical Sketch

Dr. Gatu Johnson has been a member of the PSFC High Energy Density Physics group since 2010. Her current primary responsibilities include managing the group's linear electrostatic ion accelerator lab for diagnostic development, and acting as a co-responsible scientist involved in maintaining and analyzing data from two large magnetic neutron spectrometers [the Magnetic Recoil neutron Spectrometers (MRS)] installed at the OMEGA laser and the National Ignition Facility (NIF). She is also deeply involved in running and supporting experiments at the OMEGA laser facility, with a particular focus on plasma nuclear science.

 

The MRS’s on OMEGA and the NIF provide the essential performance parameters of yield and areal density to guide the cryogenic programs at each facility toward continuously improved performance. Dr. Gatu Johnson has uniquely used the MRS on the NIF to probe collective fuel motion in various implosions. Her findings seem to suggest that fuel kinetic energy in ignition implosions remains during burn along the symmetry axis of the hohlraum, which has a significant impact on the implosion performance. In addition to supporting the main programs at OMEGA and the NIF, Maria has also used the MRS’s on both facilities for basic nuclear science experiments, including probing the T-T reaction at low energies and adapting the OMEGA MRS to measure the charged-particle spectra from the T-3He reaction.

 

Dr. Gatu Johnson's graduate work at the Uppsala University Department of Physics and Astronomy started with the construction and installation of a novel DD neutron spectrometer, called TOFOR, at the Joint European Torus (JET) magnetic confinement fusion research facility. As a graduate student, she had the unique experience of guiding the TOFOR project from construction and component testing through installation, commissioning and calibration to measurements and physics interpretations of the results. She was responsible for maintaining and running the instrument during a number of JET experimental campaigns. Her work involved simulations of spectrometer characteristics as well as of the measured neutron spectra to interpret the data.

 

In her career to date, Maria has been the first author of 8 papers in Physics of Plasmas, Nuclear Fusion, Plasma Physics and Controlled Fusion, Nuclear Instruments and Methods A and Review of Scientific Instruments, and co-authored more than 50. She won the PPCF Poster Prize for best student poster at the European Physical Society Plasma Physics Conference in Sofia, Bulgaria, 2009, and the poster prize for best Poster by a Post Doc at the NIF User Group meeting in February 2013. She gave the invited talk on NIF neutron spectrometry at the High Temperature Plasma Diagnostic conference in Monterey, CA, in May 2012 and an invited talk at the Rising Stars in Nuclear Science and Engineering Symposium at MIT in March 2013.

 

Education and Training

 

M.Sc.

Engineering Physics, Uppsala University, Sweden, 2003.

 

Ph.D.

Applied Nuclear Physics, Uppsala University, Sweden, 2010.

 

Postdoctoral
Associate

MIT Plasma Science and Fusion Center, 2010-2013.

 

Research and Professional Experience

 

2013-present

Research Scientist at the Massachusetts Institute of Technology Plasma Science and Fusion Center

 

2010-2013

Post doc at the Massachusetts Institute of Technology Plasma Science and Fusion Center.

 

2004-2010

PhD position at the Department of Physics and Astronomy, Uppsala University.
Repeatedly seconded to work at the Joint European Torus fusion research facility in Oxford, UK..

 

Selected Bibliography

 

1)
M. Gatu Johnson, D.T. Casey, J.A. Frenje, C.-K. Li, F.H. Séguin, R.D. Petrasso, R. Ashabranner, R. Bionta, S. LePape, M. McKernan, A. Mackinnon, J.D. Kilkenny, J. Knauer and T.C. Sangster, “Measurements of collective fuel velocities in DT exploding pusher and cryogenically layered DT implosions on the NIF”, Physics of Plasmas 20, 042707 (2013).
2)
J.A. Frenje, R. Bionta, E.J. Bond, J.A. Caggiano, D.T. Casey, C. Cerjan, J. Edwards, M. Eckart, D.N. Fittinghoff, S. Friedrich, V.Yu. Glebov, S. Glenzer, G. Grim, S. Haan, R. Hatarik, S. Hatchett, M. Gatu Johnson, O.S. Jones, J.D. Kilkenny, J.P. Knauer, O. Landen, R. Leeper, S. Le Pape, R. Lerche, C.K. Li, A. Mackinnon, J. McNaney, F.E. Merrill, M. Moran, D.H. Munro, T.J. Murphy, R.D. Petrasso, R. Rygg, T.C. Sangster, F.H. Séguin, S. Sepke, B. Spears, P. Springer, C. Stoeckl and D.C. Wilson, “Diagnosing implosion performance at the National Ignition Facility (NIF) by means of neutron spectrometry”, Nucl. Fusion 53, 043014 (2013).
3)
D. T. Casey, J. A. Frenje, M. Gatu Johnson, F. H. Séguin, C. K. Li, R. D. Petrasso, V. Yu. Glebov, J. Katz, J. Magoon, D. D. Meyerhofer, T. C. Sangster, M. Shoup, J. Ulreich, R. C. Ashabranner, R. M. Bionta, A. C. Carpenter, B. Felker, H. Y. Khater, S. LePape, A. MacKinnon, M. A. Mckernan, M. Moran, J. R. Rygg, M. F. Yeoman, R. Zacharias, R. J. Leeper, K. Fletcher, M. Farrell, D. Jasion, J. Kilkenny, and R. Paguio, “The magnetic recoil spectrometer for measurements of the absolute neutron spectrum at OMEGA and the NIF”,Rev. Sci. Inst. 84, 043506 (2013).
4)
M. Gatu Johnson, J.A. Frenje, D.T. Casey, C.K. Li, F.H. Séguin, R. Petrasso, R. Ashabranner, R.M. Bionta, D.L. Bleuel, E.J. Bond, J.A. Caggiano, A. Carpenter, C.J. Cerjan, T.J. Clancy, T. Doeppner, M.J. Eckart, M.J. Edwards, S. Friedrich, S.H. Glenzer, S.W. Haan, E.P. Hartouni, R. Hatarik, S.P. Hatchett, O.S. Jones, G. Kyrala, S. Le Pape, R.A. Lerche, O.L. Landen, T. Ma, A.J. MacKinnon, M.A. McKernan, M.J. Moran, E. Moses, D.H. Munro, J. McNaney, H.S. Park, J. Ralph, B. Remington, J.R. Rygg, S.M. Sepke, V. Smalyuk, B. Spears, P.T. Springer, C.B. Yeamans, M. Farrell, D. Jasion, J.D. Kilkenny, A. Nikroo, R. Paguio, J.P. Knauer, V. Yu Glebov, T.C. Sangster, R. Betti, C. Stoeckl, J. Magoon, M.J. Shoup III, G.P. Grim, J. Kline, G.L. Morgan, T.J. Murphy, R.J. Leeper, C.L. Ruiz, G. W. Cooper and A. J. Nelson, “Neutron spectrometry - An essential tool for diagnosing implosions at the National Ignition Facility (invited)”, Rev. Sci. Instrum. 83 (2012) 10D308.
5)
D. T. Casey, J. A. Frenje, M. Gatu Johnson, M. J.-E. Manuel, N. Sinenian, F. H. Seguin, C. K. Li, R. D. Petrasso, P. B. Radha, J. A. Delettrez, V. Yu Glebov, D. D. Meyerhofer, T. C. Sangster, D. P. McNabb, P. A. Amendt, R. N. Boyd, S. P. Hatchett, S. Quaglioni, J. R. Rygg, I. J. Thompson, and A. D. Bacher, “Measurements of the T(t,2n)4He neutron spectrum at low reactant energies from inertial confinement implosions”, Phys. Rev. Lett. 109, 025003 (2012).
6)
D. T. Casey, J. A. Frenje, M. Gatu Johnson, M. J.-E. Manuel, H. G. Rinderknecht, N. Sinenian, F. H. Seguin, C. K. Li, and R. D. Petrasso, P. B. Radha, J. A. Delettrez, V. Yu Glebov, D. D. Meyerhofer, and T. C. Sangster, D. P. McNabb, P. A. Amendt, R. N. Boyd, and J. R. Rygg, H. W. Herrmann and Y. H. Kim and A. D. Bacher, “Evidence for stratification of deuterium-tritium fuel in inertial confinement fusion implosions”, Phys. Rev. Lett. 108, 075002 (2012).
7)
M. Gatu Johnson, E. Andersson Sundén, M. Cecconello, S. Conroy, G. Ericsson, J. Eriksson, G. Gorini, C. Hellesen, V. Kiptily, M. Nocente, S. Sangaroon, S. E. Sharapov, M. Tardocchi, D. van Eester, M. Weiszflog, and JET EFDA Contributors, “Neutron spectrometry of JET discharges with ICRH-acceleration of helium beam ions”, Rev. Sci. Instrum. 81 (2010) 10D336.
8)
M. Gatu Johnson, S. Conroy, M. Cecconello, E. Andersson Sundén, G. Ericsson, M. Gherendi, C. Hellesen, A. Hjalmarsson, A. Murari, S. Popovichev, E. Ronchi, M. Weiszflog, V.L. Zoita and JET-EFDA Contributors, “Modelling and TOFOR measurements of scattered neutrons at JET”, Plasma Phys. Control. Fusion 52 (2010) 085002 (29pp).
9)
M. Gatu Johnson, C. Hellesen, E. Andersson Sundén, M. Cecconello, S. Conroy, G. Ericsson, G. Gorini, M. Nocente, E. Ronchi, M. Tardocchi, M. Weiszflog and JET EFDA contributors, “Neutron emission levels during the ITER zero-activation phase”, Nucl. Fusion 50 (2010) 084020 (5pp).
10)
M. Gatu Johnson, C Hellesen, E Andersson Sundén, M Cecconello, S Conroy, G Ericsson, G Gorini, V Kiptily, M Nocente, S Pinches, E Ronchi, S Sharapov, H Sjöstrand, M Tardocchi, M Weiszflog1 and JET EFDA contributors, “Neutron emission from beryllium reactions in JET deuterium plasmas with 3He minority”, Nucl. Fusion 50 (2010) 045005 (14pp).
11)
C. Hellesen, M. Gatu Johnson, E. Anderson Sundén, S. Conroy, G. Ericsson, E. Ronchi, H. Sjöstrand, M. Weiszflog, G. Gorini, M. Tardocchi, T. Johnson, V.G. Kiptily, S. D. Pinches, S. E. Sharapov and JET EFDA contributors, “Neutron emission generated by fast deuterons accelerated with ion cyclotron heating at JET”, Nucl. Fusion 50 (2010) 022001 (5pp) (Letter).
12)
M. Gatu Johnson, L. Giacomelli, A. Hjalmarsson, J. Källne, M. Weiszflog, E. Andersson Sundén, S. Conroy, G. Ericsson, C. Hellesen, E. Ronchi, H. Sjöstrand, G. Gorini, M. Tardocchi, A. Combo, N. Cruz, J. Sousa, S. Popovichev and JET-EFDA contributors, “The 2.5-MeV neutron time-of-flight spectrometer TOFOR for experiments at JET”, Nuclear Instruments and Methods in Physics Research A 591 (2008) 417-430.
13)
M. Gatu Johnson, L. Giacomelli, A. Hjalmarsson, M. Weiszflog, E. Andersson Sundén, S. Conroy, G. Ericsson, C. Hellesen, J. Källne, E. Ronchi, H. Sjöstrand, G. Gorini, M. Tardocchi, A. Murari, S. Popovichev, J. Sousa, R. C. Pereira, A. Combo and N. Cruz, “The TOFOR neutron spectrometer and its first use at JET”, Rev. Sci. Instrum. 77 (2006) 10E702.
 

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