Once the file COORD.DAT has been written, locate POLY.FOR in the software package.  A few modifications such as total number of coordinates and total number of planes will have to be changed to fit your instrument, and when this is done, an execution of the program will output a file labeled COEFF.DAT that is simply a listing of the coefficients of the planes needed by the main trajectory program.

It turns out that only a few changes must be made to the trajectory programs.  In particular, be sure in CHECHITSEN1 (in subroutines CHECKHIT and FINDVERT) that the parameters MAXSURF and MAXCOO are changed to fit your data.  This same change is also necessary in TRACKSUB5, subroutine GEOM.  Another change in CHECHITSEN1 are the parameters NGAMAP, NLOWAP, and NOPAP, which are simply the numbers of those special planes such as the open aperture.  In the case of the HISCALE instrument, I only had to worry about the particle escaping through the open aperture which is plane #40--hence I set NOPAP = 40.

A9.12.3  Magnetic Field

Next, appropriate changes in the B-field program must be made.  The four main programs to be concerned with are DMAIN1, DMAINTESTIN1, FDMOD1, and PLOTR4MYY1. 

The first thing to do is to find the B-field data for your particular instrument.  Hopefully the data is given in grid-like fashion as it was for Voyager and Ulysses.  That is, before the instrument was launched, someone measured the field strength at various places within the deflection system.  For the case of HISCALE, the points all lay in the z=+.1", -.1", and 0" planes (Shodhan's coordinates).  Your task is to find this data for your instrument and modify the parameters in the file FDMOD1.CMN so that the model you create most closely fits the data points.  Outlined below is a list of the specific steps taken to model the B-field for HISCALE.

Step 1.  Find the calibration data points for your instrument.  If data was taken in more than one plane, start with the z=0 plane first.

Step 2.  Create the file BFIELD.DAT; this program is opened by DMAIN1, and is simply a listing of the data points in Step 1 in units of Gauss.  The main program reads the data points in a certain  order.  Study these loops in DMAIN1 before typing in the data points.

Step 3.  Adjust array dimensions in DMAIN1 so that they are compatible with your data set.  This involves variables NX, NY, and arrays MAGB, NORMB, etc.  Again, this will take some study of the main program.  One thing you can do is to look at the modifications I have made to fit the data points of Kohl; refer to Section A9.7 and the modifications to DMAIN1 at the end of this thesis.

Step 4.  Do similar array adjustments in DMAINTESTIN1.

Step 5.  There are a few adjustments to be made to PLOTR4MYY1.  Specifically, the values of XMIN, XMAX, YMIN, and YMAX need to be adjusted.  Study the purpose of these variables.

Step 6.  Modify FDMOD1.CMN to fit your geometry.  For example, the parameter ANGLE is the angle between the y-axis and the plane of the magnetic slab.  LENGTH and WIDTH are parameters describing the length and width of each magnet (or part of a magnet if you have chosen to break it up into pieces).  XL, YL, and ZL are the translation parameters described earlier.

Parameters A0 and B0 determine the magnitude of the linear fall-off of magnetization, and actual values for these two variables must be determined by a trial and error approach.  M0 is an overall background magnetization

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