OBJECT     = INSTRUMENT
INSTRUMENT_HOST_ID             = VEGA2
INSTRUMENT_ID                  = SP1

OBJECT     = INSTRUMENT_INFORMATION
INSTRUMENT_NAME                = "DUST IMPACT PLASMA DETECTOR"
INSTRUMENT_TYPE                = "ELECTRODE COLLECTOR"
INSTRUMENT_DESC                = "
  This instrument detects the electric charges contained in the plasma cloud generated                                            
by a solid particle impacting on a gold target. The principle of this technique is similar                                        
to that adopted for the impact plasma detectors of SP-2. The magnitude of the positive                                            
and negative charges is proportional to the mass of the particle Q=Am, where                                                      
A= 10**3C/s for an impact velocity of 78 km/s.                                                                                    
   The SP-1 system includes two similar detectors. Each unit is made up of                                               
a base plate (1) covered by a gold target (2) at zero potential, perpendicular to the dust                                        
flow, and an array of strip collectors (4). The collectors are parallel to the dust flow;                                         
they are mounted on an insulator (3) and their edge is protected from impacts by a                                                
shield (5) connected electrically to the structure. Adjacent collectors are biased at                                             
potentials of 30 V, with opposite polarities. The two sets of electrodes in each detector                                         
detect a positive and a negative current pulse, which are analysed and recorded by the                                            
electronics unit. The entrance to one detector is covered by a plastic foil, to obtain                                            
additional information on density and/or calibration factor. The characteristic                                                   
parameters of SP-1 are given in Table 8.                                                                                          
                                                                                                                                  
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Table 8. Dust Particle Impact Plasma Detector characteristics                                                                     
                                                                                                                                  
Target material                             Gold (0.1 mm)                                                                         
Toil sensor area                            160 cm**2, one sensor covered with 0.6 and                                            
                                            2 micro m thick plastic foil on Vegas-1 and 2, resp.                                  
Impact charge range                        3x10**-14  -10**-8 C                                                                   
Estimated mass range                       3x10**-17  -10**-11 g                                                                  
Integration time                            2 s (high data rate)                                                                  
                                            2.5 min (low data rate)                                                               
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"
END_OBJECT = INSTRUMENT_INFORMATION                      

OBJECT     = INSTRUMENT_REFERENCE_INFO
REFERENCE_KEY_ID               = "ESA-SP1066"
END_OBJECT = INSTRUMENT_REFERENCE_INFO

END_OBJECT = INSTRUMENT