This program, which is not operative now (Jan 2002), is for tuning the
longitudinal knobs (amplitude & phase) in the high-energy Linac.  This
technique is based on the work of former Linac Engineer, Tom Owens, which
is based on research at Los Alamos.  

The basic idea is that one can calculate the effect of the turning of
these two knobs on the time-of-flight (velocity) of the beam.
The 'signature' of this measured time-of-flight signal is recorded, and the
program attempts to fit what the actual gradient and phase would be for 
the measured signature.  Then it can tell the user how to change these 
parameters to get closer to their 'design' values.

The measurement is made using either the resistive wall-current monitors in
the Linac, or using BPM plates.  The raw signal from the WCM is compared
to the 201 MHz reference line phase, producing a phase difference, which
is plotted against the phase of the RF gradient (which the program is 
changing).  The details of this plot are rather strongly dependent on 
the actual phase and gradient in a HEL module.

This program should be used only by senior Linac scientists and 
engineers.

Elliott McCrory