USRBIN, DOSE: Which units are used to express scored absorbed dose?

Dear FLUKA users,

Which units are used to express scored absorbed dose? The documentation says:

> Energy deposition will be expressed in GeV per cm3 per unit primary weight.
> Doses will be expressed in Gy per unit primary weight.

I use USRBIN and DOSE to score absorbed dose in a water phantom, see the following cards:

USRBIN 11. DOSE -40. 80.0 0.0 30.0Dose
USRBIN 0.0 0.0 0.0 160. 1. 60.&

The value reported by FLUKA for the surface of the water phantom is 5.92283905e-3. The scoring was performed for protons with kinetic energy of 0.2 GeV in a cylinder with radius r = 0.5 cm and height h = 0.5cm. A simple estimate of the absorbed dose based on the mass stopping power Sm(0.2 GeV) = 4.492 MeV cm^2/g gives:

D = energy_imparted / mass = (Sm * h * rho) / (pi * r^2 * h * rho) = Sm / (pi *r^2) = 5.72e-3 GeV/g = 9.15e-10 Gy.

The value reported by FLUKA is similar to the estimate expressed in GeV/g, but the fluka2008.manual says that doses are expressed in Gy. I'm confused.

Regards,
Alexandr

--
Alexandr Malusek
Department of Medical and Health Sciences
Division of Radiological Sciences / Radiation Physics
Faculty of Health Sciences
SE-581 85 Linköping
Sweden