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Galileo Energetic Particles Detector

Space Science Reviews Article: CMS

The Composition Measurement System

The CMS is designed to measure the composition in the Jovian environment from energies of >~10 keV/nucl to >10 MeV/nucl. This system contains two types of energetic particle telescopes, shown here.

Detail of the EPD CMS detector head.

A small time-of-flight (TOF) telescope looks in the zero degree direction while a pair of deltaE x E solid state detector telescopes (JK detectors) covering higher energies are oriented in the 180 degree direction. Energy coverage is summarized here.

Graphical summary of EPD energy and species rate channel coverage. Additional high energy resolution and detailed species identification are obtained from pulse height analysis data gathered simultaneously with the rate channel data show.

CMS Channel Descriptions

Channel         Species         Energy Range    Geometric Factor
Name                            (MeV nucl^-1)     (cm**2 sr)
TP1		protons		0.08-0.22	0.007
TP2		protons		0.22-0.54	0.007
TP3		protons		0.54-1.25	0.007
TA1		alphas		0.027-0.155	0.007
TA2		alphas		0.155-1.00	0.007
TO1		medium nuclei	0.012-0.026	0.007
TO2		medium nuclei	0.026-0.051	0.007
TO3		medium nuclei	0.051-0.112	0.007
TO4		medium nuclei	0.112-0.562	0.007
TS1		intermediate	0.016-0.030	0.007
TS2		intermediate	0.030-0.062	0.007
TS3		intermediate	0.062-0.31	0.007
TH1		heavy nuclei	0.02 -0.20	0.007
TACS		singles
STARTS		rates

Delta E x E
CA1		alphas		0.17- 0.49
CA3		alphas		0.49- 0.68
CA4		alphas		0.68- 1.4
CM1		medium nuclei	0.16- 0.55
CM3		medium nuclei	0.55- 1.1
CM4		medium nuclei	1.1 - 2.9
CM5		medium nuclei	2.9 -10.7
CN0		intermediate	1.0 - 2.2
CN1		intermediate	2.2 -11.7
CH1		heavy nuclei	0.22- 0.33
CH3		heavy nuclei	0.33- 0.67
CH4		heavy nuclei	0.67- 1.3
CH5		heavy nuclei	1.3 -15.0
JaS		singles rates
JbS		singles rates
KS		singles rates

TOF versus energy observed in detector KT. Discriminator levels defining the indicated TOF rate channels (solid lines), predicted TOF vs E curves (dashed lines) ,and data from accelerator calibrations (points) are shown.
Energy loss in detector J, (delta E), versus energy measured in detector K, (E). Discriminator levels defining the indicated rate channels, predicted delta cross E curves, and data from accelerator calibrations are shown.
Block diagram of CMS analog electronics.

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Updated 10/18/02, T. Hunt-Ward