Hello everyone:
I am comparing the cosmic ray flux generated by CRY (https://nuclear.llnl.gov/simulation/main.html) and would like to compared that with some existing known flux plots e.g. \Phi /cm^2/s and/or e.g. \Phi /cm^2/MeV/s. This is, therefore, more an exercise to reproduce the plots, rather than a discovery. After I generate, say muons, I filled a histogram with uniform bins (between 10^{-5} MeV to 10^{5} MeV) embedded in a canvas set with log scale in x and y directions:
h=ROOT.TH1F(particle+'_'+altitude+' m_histogm',particle+'_'+altitude+' m',10000000,0.0,100.0)
However, the plots do not match with the expected flux as seen from EXPACS page: https://phits.jaea.go.jp/expacs/. Nice tables of energy (MeV) vs flux (/cm^2/MeV/s) or
energy (MeV) vs flux (/cm^2/s) are available and one can easily get a TGraph to see the consistency with the histogram-view.
Later, I tried do change to non-uniform bins:
nbins = 100;
xmin = 1e-5;
xmax = 1e+5;
logxmin = ROOT.TMath.log10(xmin);
logxmax = ROOT.TMath.log10(xmax);
binwidth = (logxmax-logxmin)/nbins;
xbins = [None]*(nbins+1)
xbins[0] = xmin
for i in range(nbins+1):
xbins[i] = xmin + ROOT.TMath.Power(10,logxmin+i*binwidth)
print(str(xbins[i])+' = '+str(xmin)+' + 10^{'+str(logxmin)+'+'+str(i)+'*'+str(binwidth)+'}, '+str(ROOT.TMath.Power(10.0,logxmin+i*binwidth))+', type '+str(type(xbins[i])))
#print(str(xbins))
h=ROOT.TH1F(particle+'_'+altitude+' m_histogm',particle+'_'+altitude+' m',nbins,array('f',xbins))
This one seems to be more close to EXPACS plots, but I am still not convinced, as not all the plots for all the particles show similar behavior. In this case also, I cannot understand if the bin-widths are chosen wisely. Should they all be 1 MeV?
There seems to be a couple of issues going on here:
(a) The first part is: I cannot understand how to compare the frequency of the TH1F with the plot for which the well defined units are available.
(b) There are other normalization related issues, that is specific to CRY simulation - but these are minor to me, at this moment.
Can anyone please throw light on how to check this consistency? I understand that this must be a simple problem - just I cannot understand how to do it.
Any help will be appreciated,
Regards,
Kolahal