HR: 0830h
AN: SM11C-1188    [PDF]
TI: Reassessment of Calibrations of Precipitating Particle Sensors on DMSP Spacecraft
AU: * Kadinsky-Cade, K
EM: Katharine.Kadinsky-Cade@hanscom.af.mil
AF: Air Force Research Laboratory, AFRL/VSBX, Hanscom AFB, MA 01731 United States
AU: Holeman, E
AF: Boston College, Institute for Scientific Research, 140 Commonwealth Ave., Chestnut Hill, MA 02467 United States
AU: Rich, F
AF: Air Force Research Laboratory, AFRL/VSBX, Hanscom AFB, MA 01731 United States
AU: Hardy, D
AF: Air Force Research Laboratory, AFRL/VS, Kirtland AFB, NM 87117 United States
AB: Data from the precipitating particle spectrometers on the spacecraft of the Defense Meteorological Satellite Program (DMSP) are provided by AFRL and widely used. The calibrations are done as carefully as possible in a vacuum chamber before flight. However, until now, there has been minimal accounting for changes that take place between calibration and launch, which is often several years, and changes that take place after launch. In the past, the only checking we have done is to compare in-flight auroral particle data from newly launched spacecraft with data from similar instruments on older spacecraft in the same orbit plane. Since two spacecraft almost never cross the auroral zones simultaneously, this has left us with levels of uncertainty of as much as a factor of 2 on newly launched spacecraft. Older spacecraft may have had larger uncertainties because we have not accounted for degradation of the channeltron detectors. We have recently used the flux of MeV particles in the South Atlantic Anomaly region as a standard for determining the degradation of the detectors. In addition, we have used the particle flux on the low-latitude side of the dayside cusp as a standard for changes in the calibration constant between the times of vacuum chamber testing and launch. Both of these sources have variations, especially with respect to the 11-year solar cycle, but if carefully used, they are much steadier sources of particles than any other location available. The result is a new set of time-dependent calibrations, which will be released at the meeting.
DE: 2716 Energetic particles, precipitating
DE: 2794 Instruments and techniques
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting