# DOSE-EQ and DOSE Question

Dear FLUKA users and experts!
I want to get the dose size (the dose unit is Gy). I see the manual as shown in the figure.

According to this description, I understand that: the USRBIN Card (select the dose) obtains the dose.The calculation method is: Dose multiplied by 1.60217646E-7 multiplied by Number multiplied by volume (Note: number is the number of particle runs, and V is the geometry of interest) example:1.4901E-13 x 1.60217646E-7 x 1E-6 x 253.34. Is the unit of calculation result Gy?

My input file：
Proton.inp (11.1 KB)

Cheers,
Chailin

Dear @CHAILIN ,

Your questions has multiple aspects, so allow me to respond in steps.

1. When scoring DOSE in a USRBIN, the results are given to you in GeV/g/primary. Then, if you multiply by 1.60217646E-7, your result is converted in Gy/primary. Therefore, there is no need to normalize by the volume. ( !!! Unless your are using a REGION mesh. See point 2 !!!)

2. You are using a R-Phi-Z mesh, therefore FLUKA gives you the results already normalized by the volume. If you were using a REGION mesh, then you would need to normalize (DIVIDE your results by the volume of the region) by the volume since FLUKA does not know the volume of the regions.

3. Now, once you have your result in Gy/primary, multiplying your results by the number of primaries you ran in the simulations makes little sense. What is more logical to do is to multiple by the number of primaries that resembles the experimental setup you are trying to simulate/emulate.

Cheers,
Anna

Dear Anna,
Thanks for your answer. In the USRBIN Card, Select R-Z for the region of interest. According to your explanation, I only need to the simulation result multiply by 1.60217646E-7.
Dear Anna,I have another problem that is not very clear. Problem Description: FLUKA simulation results are normalized. I understand that the number of runs is different, and the final normalization results should be similar. I simulate two times of particle runs (10e6 and 10e5), but the final normalization results are very different. Did I understand it wrong at the beginning?

Cheers,
Chailin

Dear @CHAILIN ,
I am sorry, but I do not understand your question. What are you trying to compare? What is the value you’re looking at? FLUKA results are normalized by primary (weight). Therefore, if you run twice the same input file without any modification except for the number of primaries, your results will be compatible within statistical uncertainty. Of course this is if you run enough statistics and your results are statistically significant. What is the statistical uncertainty on the value your are looking at?

Cheers,
Anna