;+ ; Project : HESI ; ; Name : PLOT_GD_CALC ; ; Purpose : Calculate energies to use for the Diffraction limited portion of ; Relative modulation amplitude (from about 1 to 100 keV) ; Use either manual reduction in modulation amplitude or the standard ; 10,50, and 100% reductions & generate energies based on division of 10 ; in between the peak and trough ; ; ; Category : HESI ; ; Explanation : The HESI grid collimator physical dimensions are used with ; together with the Xray cross-sections to calculate the ; transmission functions describing the performance of the HESI ; collimator system. ; ; Use : plot_gd_calc,XX,man_rmod_amp,e_peak,collim,harm,e_diff_manual,e_diff_fl,$ ; e_diff_10,e_diff_50,grid_sep,pitch,density,thickness,ener_pl,en_xax,st_en,rel_mod_50,$ ; mod_amp,en1,tot_y,new_mod,new_rel, rmod_amp=rmod_amp ; ; Inputs : XX - cross_section arrays vs energy ; Collim - collimator number, starts at 1 ; Man_rmod_amp - Input relative modulation amplitude, as a percent ; E_peak - Energy (keV) of peak ? ; Harm - Harmonic number for modulation calculation ; E_diff_manual- energies corresponding to 1st 3 harmonic numbers and Man_rmod_amp. ; E_diff_fl - energies corresponding to 1st 3 harmonic numbers and 0 modulation. ; E_diff_10 - energies corresponding to 1st 3 harmonic numbers and 90% modulation. ; E_diff_50 - energies corresponding to 1st 3 harmonic numbers and 50% modulation. ; Grid_sep- grid separation distance in mm ; Pitch - Array of grid pitches in mm ; Density - Array of Density of grid materials in gm/cm3 ; Thickness - Array of grid thicknesses in mm ; Opt. Inputs : None ; ; Outputs : None ; Ener_pl - Plot energies in keV ; En_xax - Exact energies for calculation ; St_en - Indices into sorted energies ; Rel_mod_50 -Transmission limited modulation amplitude ; Mod_amp - Diffraction limited modulation amplitude ; En1 - New sorted energies ; Tot_y - total modulation amplitude defined on En1 ; New_mod - Transmission limited mod amplituded defined on En1 ; New_rel - Diffraction limited mod amplitude defined on En1 ; ; ; Opt. Outputs: None ; ; Keywords : RMOD_AMP- User input value of relative mod amplitude for which ; energies need to be found. ; ; Calls : ; ; Common : None ; ; Restrictions: ; ; Side effects: None. ; ; Prev. Hist : Written by Eric Carzon, 1993 ; ; Modified : Version 2, RAS, 16-apr-1997 ; Version 3, richard.schwartz@gsfc.nasa.gov, relax diffraction solution to 99% from 100%. ; 5-jan-1998. ;- Pro plot_gd_calc,XX,man_rmod_amp,e_peak,collim,harm,e_diff_manual,e_diff_fl,$ e_diff_10,e_diff_50,grid_sep,pitch,density,thickness,ener_pl,en_xax,st_en,rel_mod_50,$ mod_amp,en1,tot_y,new_mod,new_rel, rmod_amp=rmod_amp checkvar, enrg_limits, [0.1, 2e4] ;limits on energy in keV ; Look for the manual keyword, if the user has specified a reduction in ; modulation amplitude, then use that value in energy calucations ; Otherwise calculate red. in mod. amplitude effects at 10,50, &100% red. ; If keyword_set(rmod_amp) then begin man_rmod_amp = 1 goto, manual_rmodamp endif ; ; initialize arrays for 10,50, 100%, 0% reduction in mod. amplitude from ; the peak value of 1 for 12 collimators at 3 harmonics. ; gdiff = grid_diffraction([0.90,0.50,0.0,0.99],3,pitch,grid_sep, $ elim=0.1) E_diff_10= gdiff(*,*,0) E_diff_50= gdiff(*,*,1) E_diff_fl= gdiff(*,*,2) e_peak = gdiff(*,*,3) goto, skip_manual ; passes by the manual reduction (user defined) ;in modulation amplitude, rmodamp:reduction in mod. amp. ; ; User input value for reduction in modulation amplitude from diffraction. ; manual_rmodamp: c1 = 1.-(rmod_amp/100.) ; calculate diffraction limit (1-reduction) gdiff = grid_diffraction([c1, 0.99],3,pitch,grid_sep,elim=0.1) e_diff_manual = gdiff(*,*,0) e_peak = gdiff(*,*,1) skip_manual: ; ; The collim(ators) are numbered 1 thru Ngrids, generate the array index, igrid. ; igrid = collim -1 if (man_rmod_amp eq 1) then begin ener_pl = [1.257,e_peak(igrid,harm-1),e_diff_manual(igrid,harm-1),e_diff_fl(igrid,harm-1), e_diff_fl(igrid,harm-1)/3.,$ e_diff_fl(igrid,harm-1)/5.] en_xax = [ener_pl,(findgen(10)*.01)+1,(findgen(891)*.01)+1.09,$ (findgen(98)*.1)+10,(findgen(90))+10,(findgen(10))+100,$ (findgen(90)*10)+100,(findgen(10)*10)+1000,$ (findgen(90)*100)+1000] endif else begin ener_pl = [1.257,e_peak(igrid,harm-1),e_diff_fl(igrid,harm-1),$ e_diff_50(igrid,harm-1),e_diff_10(igrid,harm-1), e_diff_fl(igrid,harm-1)/3.,$ e_diff_fl(igrid,harm-1)/5.] ; ; Odd harmonics are solutions to the diffraction equations. Need them to have sufficient ; energy density for plot to fall to zero. ; En_xax = [ener_pl,(findgen(10)*.01)+1,(findgen(90)*.1)+1,(findgen(10)*.1)+10,$ (findgen(90))+10,(findgen(10))+100,(findgen(90)*10)+100,(findgen(10)*10)+1000,$ (findgen(90)*100)+1000] endelse en_xax = en_xax > 1.0 ;Sort the elements of en_xax n_elem = n_elements(en_xax) mod_amp = fltarr(n_elem) st_en = sort(en_xax) ; ; Valid energies range from 0.1 keV to 20.0 MeV ; wnz = where( xx(*,0,igrid) ge enrg_limits(0)/1e3 and xx(*,0,igrid) lt enrg_limits(1)/1e3 ) ; create an the Diffraction limited portion of the relative ; modulation amplitude versus Energy, covering a range from ; 1-100 keV ; Mod_amp = ABSOLUTE | Cos(12.3e-7*pi*collimator length*harmonic^2) / ; 4*((.5*pitch)^2)*Energy | ; This equation can be more generally put forth as ; Modulation Amplitude = pi*harmonic^2*wavelength(lambda)/ ; 4*aperture width^2 (.5*pitch = w) ;******** 10/13/95, for grids 1,2,3 make diffraction limitation 0 by using duplicating ; relative modulation amplitude at e_peak ; ; 14-apr-1997, ras, don't understand this need explanation ; commented out next line ;if (collim ge 2 and collim le 4) then en_xax(st_en) = ener_pl(1) Mod_amp =ABS( COS( (12.39854e-7*!pi*grid_sep*harm^2)/$ (4*((.5*pitch(igrid))^2)*En_xax(st_en)) ) ) ; omod_amp deals with only the rel. mod. amplitude at peak,10,50, and 100% reductions omod_amp =ABS( COS( (12.39854e-7*!pi*grid_sep*harm^2)/(4*((.5*pitch(igrid))^2)*Ener_pl) ) ) ; Relative Mod. Amp. versus Energy for 50% transmission ; Calculate the Transmission limited portion of the relative modulation ; amplitude versus energy, covering the range 100 keV to 10000 keV ; rel_mod_50 = [exponential( (-2*thickness*Attenuation Coeff. w/ Coherent Scat.* ; density)/10 ) + 1 ] - ; [ 2*exponential( (-1*thickness*Att. Coeff. * ; density)/10)] rel_mod_50 = exp( (-2*thickness(igrid)*xx(wnz,6,igrid)*density(igrid))/10 ) +1 -$ (2*exp( (-1*thickness(igrid)*xx(wnz,6,igrid)*density(igrid))/10 )) en = ([xx(wnz,0,igrid)*1000.,en_xax] > enrg_limits(0) ) < enrg_limits(1) en1 = en(uniq(en,sort(en))) ; create a combined x array lims = limits(en_xax(st_en)) if lims(0) eq lims(1) then new_mod = mod_amp(st_en(0)) else $ new_mod = interpol(mod_amp,en_xax(st_en),en1) new_rel = interpol(rel_mod_50,xx(wnz,0,igrid)*1000.,en1) tot_y = new_mod * new_rel end