pro d17_he3calc,refl,main=main,water=water,mask=maskstring,time,phi,f1,f2,trans

                LAMP procedure to take a standard 7-run measurement of the four flipper states for a He3 calibration and return the calculated phi, f1 and f2 for the mean time of the measurements.  The calculation is from the equations in Wildes, Rev. Sci. Instrum., 70 (1999) 4241

 NECESSARY VARIABLES:

                refl=a string with the first and last of the 7 files, separated by a colon

OPTIONAL VARIABLES:

                main=a string with the numbers for a measurement of the main beam, with an empty cell

                water=the number of the workspace with the (masked) water file in it.

                                The data will be divided by this workspace if it exists

                maskstring=your choice of masking the detector, written as a string

                                                The default is no mask

OUTPUT VARIABLES:

                time=the mean time for the measurement.  The values for phi,f1,f2 and trans correspond

                                to this time

                phi=the combined polarizer/analyzer inefficiency

                f1=the first flipper inefficiency

                f2=the second flipper inefficiency

                trans=the transmission of the cell.  This is only output if 'main' is specified

e.g.  d17_he3calc,'90230:90236',main='90201',water=1,mask='box,[190,200,63,222]',time,phi,f1,f2,trans