dose  vers1.0
09-Feb-03  MJF

	   Compute the response of an imaging detector
	   using data files for spectra and detector response.

example:
	dose << EOF
	dose_file
	mAs label_flag
	EOF

standard output:

	The following is written to standard output:

	# label from dose_file
	#     Dose in mGy 
 	      ...

	where the dose is reported in mGy (1 mGy = 100 mRad)

directories/links:

        _doseTables:   link to a directory containing
                       dose files in standard format.

arguments:

	dose_file: ascii file with dose data in mGy-cm2/photon 

			line1: # label describing the object 
			line2: # date table was computed
			line2: #      min_keV max_keV dkeV
			       note first "#" is read in 6 char format
			line3: # keV  mGy-cm2/photon 
			line4...:two column table of dose data
			 	 (see definitions below)

	mAs:		product of milliamps and exposure time
			(set to 1 to keep normalization)

	label_flag:	= 0 for no printing of column labels
			= 1 for printing of column labels

associated files:

	spectra.tmp:  	spectra of photons at a particular distance.

	  note:	The spectra.tmp file must be in /cm^2 units or the routine
		will return an error. Units of either photons/ or ergs/
		can be used and the routine will do the necessary conversion.

	dose_file:	see above

method:
	dose = mAs *integral{ flux * dosePerPhoton * dE} 

	The dose table file contains values for mGy per photon/cm2.
	The units are considered to be mGy-cm2/photon.
        These are computed from a pencil beam Monte Carlo computations
        that first determines the absorbed energy in a defined
        region of an object.

	The MC computations integrate e*P(e,E) over de for a single
	input energy E to obtain the energy deposited in keV.
	Units are then converted to mGy-cm2/photon by dividing
	the ergs deposited by the product of density and
	thickness and dividing by 10 (10 ergs/gm = 1 mGy).
	Note:	1 rad = 100 ergs/gram = .01 Gray = 10 mGy
		1 keV = 1.6 x E-09 ergs
		1 mGy = .1 Rad = 100 mRad
