Dear Zainah Mubarak ,

conversion from energy to photon number is done by dividing the energy (here 90mJ) by the energy of the photon(s) (here 18MeV).

For the conversion of MeV to J you may use: 1eV ~ 1,6*10-19J. Please google for this conversion number.

Pay attention, that the remainig task is to convert 1/m2 into 1/(10cm2).

My result is 90mJ/(m2*s) ~ 31*106Ph/(10cm2*s) for 18MeV photons .

Please check*) that result and confirm it...(I may have got in trouble with the decimal powers...)

*) it is a good excercise to do the individual calculation of the numbers and the collection of the decimal powers by your own.

Best regards

G.M.

Zainah Mubarak Gerhard Martens Looks like a homework question to me...

Alan F Rawle

you are right;

thus I intended to let the detailed calculation be done by Zainah Mubarak