The Galileo Energetic Particles Detector

Galileo EPD Handbook

Chapter 1. Instrument Summary

CMS Subsystem

This section on the CMS subsystem is organized as follows:

• Overview of CMS subsystem as flown (i.e., post-Challenger) - below; please scroll down
• Post-Challenger Revisions
  • Hardware Changes
  • Telemetry and Operation Changes
  • Command Changes
  • Software Changes
  • Ground Support Equipment
  • Overview of Rework
  • Accumulator Servicing Tables
• Pre-Challenger CMS Overview (for reference)
• Analog Electronics (post-Challenger and pre-Challenger)
  • CMS Rate Channels, post-Challenger
  • CMS Rate Channels, pre-Challenger
  • Time-of-Flight Subsystem (original, pre-Challenger TOF subsystem)
• Calibrations

CMS Subsystem - Post-Challenger (as flown)

Source: The Galileo Energetic Particles Detector, D. J. Williams et al., Space Science Reviews, 60, 385, 1992 (excerpts).

The CMS is designed to measure the composition of ions in the Jovian environment from energies of ≥10 keV nucl-1 to ≥10 MeV nucl-1. This system contains two types of energetic particle telescopes, shown schematically in Figure 1-11.  A small time-of-flight (TOF) telescope looks in the 0° direction while a pair of DE x E solid state detector telescopes (JK detectors) covering higher energies are oriented in the 180° direction.

The TOF portion of CMS is a replacement of the original EPD TOF telescope built for launch in early 1986. JPL, NASA, and the Bundesministerium fur Forschung und Technologie allowed us the opportunity to take advantage of new technology in order to lower our energy threshold for composition measurements by at least a factor of ten....The new TOF telescope, its high voltage power supply, the new TOF circuitry, and the major modifications to the electronics subsystem were designed, built, tested, and integrated into the EPD in 1987 and 1988.  All instrument and spacecraft tests and calibrations were successful and were indicative of an instrument response that exceeded expectations.

CMS Channel Descriptions: Table 6

Figure 1-12a. Detail of EPD CMS detector head (as flown).

Figure 1-12b. Schematic cross-section of TOF system. Source: Critical Design Review, Dec. 1987.

Figure 1-12c. Detailed cross-section of TOF system. Source: Critical Design Review, Dec. 1987.

High Voltage Output Filter
Source: Critical Design Review, December 1987, MPAe

High Voltage Output Filter - schematic and details:

Next: Post-Challenger Revisions: Hardware Changes 

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