Digitization of ICI Data Arrays                        
                                                                              
The submitted printouts of ICI datas were digitized by the Small Bodies Node. 
Hard copy covered the time period from Sept 9 (11:00:25) through Sept 13      
(12:42:20).  On each computer printout there were two arrays of M/Q versus V  
arrays in which each value represented counts at a unique stepped parameter in
the scan.  The tables were separated for digitization and each table giving a 
running number starting with the first set of tables on Sept 9 (11:00:25).    
The filenames are listed as icinnnnc where nnnn is the running number and c is
a character to designate which M/Q range table was digitized (a for low       
mass data (1.3-3.05 amu/e-) and b for water group ions (14-32 amu/e-).        
As reported by Coplan et al (1987) there was an overflow in the instrument    
on Sept 11 (19:47) so the Sept 12 data are not included.   Figure 2 from      
Coplan et al. (1987) is included as ICIFIG2.PS.     A -1 indicates no data    
in the format of the original printout (I6), which has been preserved.        
                                                                              
Arrays are composed of scans in velocity as the M/Q values is held constant.  
For low mode, there are 14 scans beginning at 1.38 amu/e- and there are 12    
velocity steps (unequal) for each M/Q scan.  The steps are listed as follows: 
237.71 km/s, 252.61 km/s, 268.31 km/s, 285.11 km/s, 302.91 km/s, 321.71 km/s, 
341.81 km/s, 363.11 km/s, 385.81 km/s, 409.91 km/s, 435.41 km/s, 462.61 km/s. 
The process is repeated for 13 additional scans (total of 14) in the          
following order: 1.38 amu/e-, 1.48 amu/e-, 1.58 amu/e-, 1.67 amu/e-, 1.76     
amu/e-, 1.88 amu/e-, 2.00 amu/e-, 2.21 amu/e-, 2.26 amu/e-, 2.40 amu/e-, 2.54 
amu/e-, 2.70 amu/e-, 2.87 amu/e-, 3.05 amu/e-.  Counts for a "M/Q vs V" bin   
are collected every 2.97 seconds, which is one spacecraft spin; there are 420 
spins in a complete cycle which spans 21.13 min.   The time spent on each scan
is 35.72 seconds.  The sequence of scans is not continuous but interleaved    
with the other mode of sampling (M/Q 14-32 amu/e- for V=80-224 km/s); a scan  
begins every 89.3 seconds in each mode.                                       
                                                                              
For other mode, there are 14 scans beginning at 14.4 amu/e- and there are 18  
velocity steps (unequal) for each M/Q scan.   The velocity steps are follow:  
80.01 km/s, 85.01 km/s, 90.31 km/s, 95.91 km/s, 101.91 km/s, 108.31 km/s,     
115.01 km/s, 122.21 km/s, 129.81 km/s, 137.91 km/s, 146.51 km/s, 155.71 km/s, 
165.41 km/s, 175.71 km/s, 186.61 km/s, 198.31 km/s, 210.61 km/s, 223.81 km/s. 
The process is repeated for 13 additional scans (total of 14) in the          
following order: 14.4 amu/e-, 15.3 amu/e-, 16.3 amu/e-, 17.3 amu/e-, 18.4     
amu/e-, 19.5 amu/e-, 20.8 amu/e-, 22.1 amu/e-, 23.4 amu/e-, 24.9 amu/e-, 26.5 
amu/e-, 28.1 amu/e-, 29.9 amu/e-, 31.7 amu/e-.  Counts per each "M/Q vs V" bin
are collected every 2.97 seconds which is one complete spacecraft spin; there 
are 420 spins in a complete cycle that takes 21.13 min.  The time spent on    
each scan is 53.58 seconds.  The sequence of scans is not continuous but      
interleaved with the other mode of sampling (M/Q 1.38-3.05 amu/e- for         
V=237-463 km/s); a scan begins every 89.3 seconds in each mode.