spectra.tmp
22-JAN-96  MJF
11-JAN-03  MJF (revised doc file)

	File format for x-ray spectral data files: spectra.tmp

General description:

	In the xspect environment, tables of x-ray spectra are generated
	by spect_gen routines (or can be supplied from experimental or
	Monte Carlo data). A standard format has been adopted to store
	this data with unit information. Spectra may be modified by
	attenuation with atten. Spectra may be integrated or evaluated
	to determine the local exposure. Spectra may be used to determine
	detector response with detect.

Example:
	# spect_gen: 42  12.000  1   50.00
	#    99   0.5000      0.0000
	#    2   1  (unit flags)
	#  Energy     ergs/mAs-sr-keV
	    1.000        0.0000E+00
	    1.500        0.0000E+00
	    2.000        1.4350E-09
	    2.500        1.9378E-04
		.
		.
		.
  	   49.500        1.6423E+01
  	   50.000        0.0000E+00
	#  Attenuation History:
	#  1
	# molybdenum             2.5000E-03

	Note:   1. # is appended on the nondata lines to make plotting
	           with gnuplot convenient.
		2. Information is documented at the end of the file to
		   record the history of attenuation.

format definition: 

	Ascii file containing the following:

		line1: #"spect_gen:" Z  angle  waveform  kVp 
		line2: #Npts dkeV distance
		line3: #  unitcodeA unitcodeB "(unit flag)"
		line4: #"Energy" "(photons or ergs)/mAs-(cm^2 or sr)-kev"
		line(5 to Npts+4): keV spectral_value 
		line Npts+5  "Attenuation History"
		line Npts+6  N_atten (# of attenuating mats)
		lines Npts+7 to Npts+6+N_atten
		mat_name  thick
		mat_name  thick
			(ie Name and thickness of attenuators)

		note:   distance refers to distance at
			which a /sr to /cm^2 conversion was 
			made, and is non-zero only when 
			unitcodeB is 2.	

			unitcodeA = 1 for photons
			unitcodeA = 2 for ergs
			unitcodeB = 1 for sr
			unitcodeB = 2 for cm^2