Instrumentation

The dust telescope described here consists of four state-of-the-art dust instruments and a plasma monitor, PLASMON. The dust instruments have a field of view of 25° half-width implemented by extra baffles. The relatively narrow field of view of the dust telescope allows pointed observations of the dust flow. The four instruments are, a high resolution impact mass spectrometer (Cometary and Interstellar Dust Analyzer, CIDA), a dust analyzer for the determination of physical and chemical dust properties (Cosmic Dust Analyzer, CDA), a large area impact detector with trajectory analysis (Dust Detector System, D2S), and the momentum sensor ISIDE (Impact Sensor for Interstellar Dust Exploration). This selection of instruments is not mandatory. When new instruments with improved capabilities become available they should be used.

Three dust instruments share a common impact plane of 1 m2 that is divided into 9 segments. Seven segmented polyvinylidene fluoride (PVDF) targets of D2S surround the central opening for CDA. ISIDE is mounted in one corner. The positions of CDA and ISIDE can be exchanged with any D2S element, depending on the interface to the spacecraft. Figure 1 shows the dust telescope with CIDA and PLASMON attached to the baffle of the D2S dust collimators and CDA and ISIDE below. Seven of the nine collimators belong to D2S, while CDA and ISIDE have their own collimators. PLASMON monitors the plasma environment and thus supports the interpretation of the dust charge measurements. The total mass of the dust telescope is 52.2 kg. The instrument properties are given in Table 1. The instruments employ various detection techniques and have different sensitivities. CIDA and CDA have the highest sensitivity for fast particles.

3.1. The Cosmic Dust Analyzer, CDA

The Cosmic Dust Analyzer (CDA) is a modified version of the instrument flying on board the Cassini spacecraft [26], The Cassini CDA has been operated successfully since January 1999.

The CDA instrument is an impact ionization detector: A high speed particle impacts a target and becomes partially ionized. The generated impact plasma is separated in an electric field such that the electrons are detected at the target and the ions are detected at a central charge collector and a multiplier. The signals are converted to analogue voltages, which are digitized, processed, and stored in the CDA instrument computer.

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