Astrophysics and Space Sciences Transactions www.astrophys-space-sci-trans.net 1810-6528 1810-6536 5 1 2009 10.5194/astra-5-1-2009 http://www.astrophys-space-sci-trans.net/5/1/2009/ http://www.astrophys-space-sci-trans.net/5/1/2009/astra-5-1-2009.html http://www.astrophys-space-sci-trans.net/5/1/2009/astra-5-1-2009.pdf 1 13 2009-03-27 The STEREO/PLASTIC response to solar wind ions (Flight measurements and models) H. Daoudi daoudi@space.unibe.ch L. M. Blush P. Bochsler A. B. Galvin C. Giammanco R. Karrer A. Opitz P. Wurz C. Farrugia L. A. Kistler M. A. Popecki E. Möbius K. Singer B. Klecker R. F. Wimmer-Schweingruber B. Thompson Physikalisches Institut, University of Bern, 3012 Bern, Switzerland EOS SSC, University of New Hampshire, Durham, NH 03824, USA Max-Planck Institut für extraterrestrische Physik, 85740 Garching, Germany Institute for Experimental and Applied Physics, University of Kiel, 24098 Kiel, Germany NASA GSFC, Laboratory for Solar and Space Physics, Code 612.1, Solar Physics Branch, Greenbelt, MD 20771, USA The Plasma and Supra-Thermal Ion Composition (PLASTIC) instrument is one of four experiment packages on board of the two identical STEREO spacecraft A and B, which were successfully launched from Cape Canaveral on 26 October 2006. During the two years of the nominal STEREO mission, PLASTIC is providing us with the plasma characteristics of protons, alpha particles, and heavy ions. PLASTIC will also provide key diagnostic measurements in the form of the mass and charge state composition of heavy ions. Three measurements (E/qk, time of flight, ESSD) from the pulse height raw data are used to characterize the solar wind ions from the solar wind sector, and part of the suprathermal particles from the wide-angle partition with respect to mass, atomic number and charge state. In this paper, we present a new method for flight data analysis based on simulations of the PLASTIC response to solar wind ions. We present the response of the entrance system / energy analyzer in an analytical form. Based on stopping power theory, we use an analytical expression for the energy loss of the ions when they pass through a thin carbon foil. This allows us to model analytically the response of the time of flight mass spectrometer to solar wind ions. Thus we present a new version of the analytical response of the solid state detectors to solar wind ions. Various important parameters needed for our models were derived, based on calibration data and on the first flight measurements obtained from STEREO-A. We used information from each measured event that is registered in full resolution in the Pulse Height Analysis words and we derived a new algorithm for the analysis of both existing and future data sets of a similar nature which was tested and works well. This algorithm allows us to obtain, for each measured event, the mass, atomic number and charge state in the correct physical units. Finally, an important criterion was developed for filtering our Fe raw flight data set from the pulse height data without discriminating charge states. Aellig, M. R.: Freeze-in Temperatures and Relative Abundances of Iron Ions in the Solar Wind Measured with SOHO/CELIAS/CTOF, Ph.D. Thesis, University of Bern, Switzerland, 133, 1998. Allegrini,~F., Bochsler,~P., Wimmer-Schweingruber,~R F., and Wurz,~P.: Determination of Low-Energy Ion Induced Electron Yields from Thin Carbon Foils, Nucl. Instrum. Meth. B., 211, 487–494, 2003. Arnaud,~M. and Rothenflug,~R.: An Update evaluation of recombination and ionization rates, Astron. Astrophys., Suppl., 60, 425–457, 1985. Arnaud,~M. and Raymond,~J.: Iron ionization and recombination rates and ionization equilibrium, Astrophys. J., 398, 394–406, 1992. Betz, G. and Wien, K .: Energy and angular distributions of sputtered particles, Int. J. Mass. Spectr, 140, 1–110, 1994. Biersack, J. P.: The Calculation of Ion Ranges in Solids with Analytical Solutions, Springer series on electrophysics, 10, 157–166, 1982. Blush,~L M., Bochsler,~P., Daoudi,~H., Galvin,~A., Karrer,~R., Kistler,~L., Klecker,~B., Möbius,~E., Opitz,~A., Popecki,~M., Thompson,~B., Wimmer-Schweingruber,~R F., and Wurz,~P.:\vadjust Development and calibration of major components for the STEREO/ PLASTIC (plasma and suprathermal ion composition) Instrument, Adv. Space Res., 36, 1544–1556, 2005. Bochsler, P.: Abundances and charge states of particles in the solar wind, Reviews of Geophysics, 38, 247–266, 2000. Daoudi, H.: First STEREO/PLASTIC measurements of Fe charge states in the solar wind; presentation of a new method for flight data analyses, PhD.\ Thesis, Univ. of Bern, Switzerland, 176, 2008. Galvin,~A B., Kistler,~L M., Popecki,~M A., Farrugia,~C J., Simunac,~K D C., Ellis,~L., Möbius,~E., Lee,~M A., Boehm,~M., Carroll,~J., Crawshaw,~A., Conti,~M., Demaine,~P., Ellis,~S., Gaidos,~J A., Googins,~J., Granoff,~M., Gustafson,~A., Heirtzler,~D., King,~B., Knauss,~U., Lavasseur,~J., Longworth,~S., Singer,~K., Turco,~S., Vachon,~P., Vosbury,~M., Widholm,~M., Blush,~L M., Karrer,~R., Bochsler,~P., Daoudi,~H., Etter,~A., Fischer,~J., Jost,~J., Opitz,~A., Sigrist,~M., Wurz,~P., Klecker,~B., Wimmer-Schweingruber,~R F., Koeten,~M., Thompson,~B., and Steinfeld,~D.: The Plasma and Suprathermal Ion Composition (PLASTIC) Investigation on the STEREO Observatories, Space Science Rev., 136, 437–486, doi:10.1007/s11214-007-9296-x, 2008. Hefti, S.: Solar Wind Freeze-in Temperatures and Fluxes Measured with SOHO/ CELIAS/CTOF and calibration of the CELIAS Sensors, Ph.D. Thesis, Univ. Bern, Switzerland, 103, 1997. Hohl, M.: MEFISTO II, Design, setup, characterization and operation of an improved calibration facility for solar plasma instrumentation, Ph.D.\ Thesis, Univ. Bern, Switzerland, 131, 2002. Karrer, R.: Ion optical calibration of the PLASTIC sensor on STEREO, Ph.D.\ Thesis, Univ. Bern, Switzerland, 207, 2007. Klein, K. M., Park, C., and Tasch,~A F.: Monte Carlo simulation of boron implantation into single-crystal silicon, Electron Devices, IEEE Transactions on, 39, 1614–1621, 1992. Marti, A., Schletti, R., and Wurz, P., and Bochsler, P.: Calibration facility for solar wind plasma instrumentation, Review of scient. instr., 72, 1354–1360, 2000. Moré,~J J., Garbow,~B S., and Hillstrom, K. E.: User guide for MINPACK-1, Argonne Nat. Lab., Techn. report ANL, 80–74, 1980. Oetliker, M.: CTOF, A Solar Wind Time of Flight Mass Spectrometer with High Charge Resolution (Numerical simulations and Calibrations), Ph.D. Thesis, Univ. Bern, Switzerland, 133, 1993. Pilz,~W., Borany,~J V., Grötzschel,~R., Jiang,~W., Posselt,~M., and Schmidt,~B.: Dependence of the silicon detector response to heavy ions on the direction of incidence (Computer simulations versus experimental data), Nucl. Instrum. Meth. A: 419, 137–145, 1998. Wimmer-Schweingruber, R. F.: Solar and galactic composition, AIP Conference Proceedings Subseries on Astronomy and Astrophysics, 598, SOHO/ACE Workshop, Bern, Switzerland, 6–9~March, 3–9, 2001. Ziegler,~J F., Biersack,~J P., and Littmark,~U.: The stopping and range of Ions in solids, Pergamon press, Inc., 1, Maxwell House, Fairview Park, Elmsford, New York 10523, U.S.A, 321, 1992. Zurbuchen, T.: Turbulence in the Interplanetary Medium and its Implications on the Dynamics of Minor Ions. Ph.D. Thesis, Univ. Bern, Switzerland, 138, 1996.