HR: 1330h
AN: SM13A-07    [Abstracts]
TI: Are Identical Twins, Truly Identical? A Comparison of Mass Spectra Recorded by "Identical" Mass Spectrometers.
AU: * Shappirio, M
EM: mark.d.shappirio@nasa.gov
AF: Goddard Space Flight Center, Greenbelt Rd., Greenbelt, MD 20771 United States
AU: Chornay, D
EM: Dennis.Chornay@gsfc.nasa.gov
AF: Goddard Space Flight Center, Greenbelt Rd., Greenbelt, MD 20771 United States
AU: Sittler, E C
EM: edward.C.Sittler@nasa.gov
AF: Goddard Space Flight Center, Greenbelt Rd., Greenbelt, MD 20771 United States
AU: Black, R
EM: rblack@swri.org
AF: Southwest Reseach Institute, PO Drawer 28510, San Antonio, TX 78228 United States
AU: Goldstein, R
EM: rgoldstein@swri.edu
AF: Southwest Reseach Institute, PO Drawer 28510, San Antonio, TX 78228 United States
AU: McComas, D J
EM: david.mccomas@swri.org
AF: Southwest Reseach Institute, PO Drawer 28510, San Antonio, TX 78228 United States
AU: Young, D T
EM: dyoung@swri.edu
AF: Southwest Reseach Institute, PO Drawer 28510, San Antonio, TX 78228 United States
AU: Funsten, H O
EM: hfunsten@lanl.gov
AF: Los Alamos National Labs, MS D466, Los Alamos, NM 87545 United States
AU: McCabe, K
EM: kmccabe@lanl.gov
AF: Los Alamos National Labs, MS D466, Los Alamos, NM 87545 United States
AU: Nordholt, J E
EM: jnordholt@lanl.gov
AF: Los Alamos National Labs, MS D466, Los Alamos, NM 87545 United States
AU: Thomsen, M F
EM: mthomsen@lanl.gov
AF: Los Alamos National Labs, MS D466, Los Alamos, NM 87545 United States
AU: Reisenfeld, D
EM: dan.reisenfeld@umontana.edu
AF: University of Montana, Dept of Physics & Astronomy 32 Campus Drive, Missoula, MT 59812
AB: When the time of flight (TOF) Ion Mass Spectrometer (IMS) for the Cassini Plasma Spectrometer (CAPS) instrument was launched, the prototype model was upgraded to be identical to the flight model electro-optically and electronically. The primary goal of the upgrade was to have an instrument which could be tested in the laboratory to help analyze and interpret the data being returned from Cassini IMS measurements at Saturn for its four year tour and after a seven year journey. Since launch the prototype model has been used to test the instruments response to a wide variety of ion beam masses, energies, fluxes and compositions, many of which could not be covered during ground calibration of the flight instrument. This testing broadened our understanding of how IMS works and responds beyond what was accomplished before launch. However, when making comparisons between calibration data taken with the flight and the prototype units using beams with the same composition and energy, some systematic differences have been observed. In particular the mass spectra generated by the prototype appear to have a shift in the TOF from that of the flight instrument, the size of which depends on both the energy and mass of the incident ion. The differences will be discussed with particular reference to potential causes. This information is important for understanding the complications in calibrating and comparing the results from instruments that are assumed to function identically, in particular as applied to future constellation missions with instrument of identical design. It may also be useful to others designing similar TOF instruments.
DE: 2116 Energetic particles, planetary
DE: 2194 Instruments and techniques
DE: 2794 Instruments and techniques
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly