THEMIS INSTRUMENT TRAINING SST Instrument Training SST 1

THEMIS INSTRUMENT TRAINING SST Instrument Training SST- 1 UCB, Dec 6, 2006

Overview Introduction • • • SST stands for Solid State Telescope. It measures high energy electrons and ions from about 30 ke. V to 300 ke. V. There are 8 apertures – 4 for each species. Detectors are similar to those flown on Wind and Stereo. Detectors are made up of semi conductor material that when hit by energetic particles produce a pulse. The number of pulses and their height are proportional to the number and energy of the species. Attenuators used to cut count rates at high flux levels to preserve detectors. Instrument Training SST- 2 UCB, Dec 6, 2006

Overview • • Instrument Training SST- 3 Electron sensor has foil over it to stop ions from hitting the detector. Ion sensor has magnet to deflect electrons away from sensor. UCB, Dec 6, 2006

SST ITOS Page Instrument Training SST- 4 UCB, Dec 6, 2006

SST Attenuators Actuator page contains the same information as displayed on the SST page. Instrument Training SST- 5 UCB, Dec 6, 2006

SST Telemetry • SST produces 4 types of data • • APID 453 with the ESA is moment data. Computed by the ETC Actel, this gives low resolution data of velocity, density and distribution of particles. APID 45 B and 45 E are the reduced distribution functions. Enabled during Slow and Fast Survey, they are compressed time distributions of particle count at different angles. APID 45 A and 45 D are the full distribution functions. Enabled during Slow and Fast Survey, they contain the full count of particles at different angles. APID 45 C and 45 F are burst distributions. Just like the full distributions but at a higher resolution. Note currently there are no plans to enable 45 C data during the mission (except perhaps commissioning) Instrument Training SST- 6 UCB, Dec 6, 2006

SST Commands • • SST requires the DAP board to be initialized on power up and the bias to be set for the sensors depending on the external temperature. SST Attenuators require the SMA supply from the IDPU. IACTSELECT command chooses the attenuator open or close function. IACTTIME the duration of the pulse to actuator the SMA wire. IACTFIRE turns on the voltage to actuator the attenuators. Instrument Training SST- 7 UCB, Dec 6, 2006