I tried to use USRBDX and USRYIELD to calculate the energy spectrum of carbon beam. The results from these two cards were different in values though the shape of curves were similar. The distribution of proton and carbon are in the graphs as below. I read the manual but still do not have an idea for the differences.
The flair and inp files are attached.
Thanks in advance for your answer.
Note that USRYIELD gives you a particle yield whereas USRBDX gives you a fluence, i.e. have you taken into account when plotting USRYIELD the area of the crossing surface? Note also when you want to score the quantities related to the beam particles only you can use BEAMPART as WHAT(2) instead of now selecting out the particles using AUXSCORE, not sure if this is indeed what you want to achieve?
Thanks a lot for your answer. But I still do not get the same results from USRBDX and USRYIELD if I considered to divide the results from USRYIELD with area of crossing surface. The value in USRYIELD will become even smaller. Please look at the attached picture. This question is still confused me.
Regarding the beam particles scored, i’d like to differentiate Li, Be,B and C from group of heavy ions by using AUXSCORE. I did this to Carbon for first try. In the attached pictures, it showed the results of carbon by using USRBDX and USRYIELD.
You forgot to multiply the USRYIELD results by 499.9 that is the extent of the (curious) particle charge interval you input in the card. USRYIELD results are double differential, i.e. divided by de and da as well, where e and a are the two selected quantities (energy and particle charge in your case). Therefore, you need to multiply back by da.
Also, as @anwaets pointed out, USRBDX gave you a fluence, while for the purposes of comparison with USRYIELD you should ask for current in the USRBDX card.
Not least, always write on the plot axes the respective quantities and units. Here it’s E [GeV] on x and dN/dEdA [GeV-1 cm-2] on y.
