Clementine Charged Particle Telescope (CPT)

Description

The Charged Particle Telescope (CPT) on Clementine was designed to measure the flux and spectra of energetic protons (3--80 MeV) and electrons (25--500 KeV). The primary goals of the investigation were to: (1) study the interaction of the Earth's magnetotail and interplanetary shocks with the Moon; (2) monitor the solar wind in regions far removed from other spacecraft as part of a multimission coordinated study; and, (3) measure the effects of incident particles on the operating ability of the spacecraft solar cells and other sensors. In order to meet the stringent limit on the mass of the instrument (<1 kg), it was implemented as a single element telescope. The telescope had a 10 degree half-angle field of view. The detector, a silicon surface-barrier type with an area of 100 sq mm and a thickness of 3 mm, was shielded so as to prevent protons below 30 MeV from reaching it from directions other than via the aperture. The aperture was covered by a very thin foil to prevent light impinging on the detector and generating noise. The signal from the detector was broken up into nine channels, the lowest six dedicated to electron detection and the highest three to protons and heavier ions.