Over the range -

PHYSICS · Multi-part · Fermi University Physics · Nuclear Physics · Radiation interactions, detection and dosimetry · Radiation interactions, detection and dosimetry

The Nucleus Resolved, Ch Radiation in matter, computed: Bethe, Klein-Nishina and what they leave out

Problem

Over the range

100

200\,\mathrm{MeV}

, the Bethe-formula range of a proton in water is well fitted by a power law

R = \alpha E^{p}, \qquad p = 1.75,

with

R

\mathrm{g\,cm^{-2}}

and

E

\mathrm{MeV}

. The integral of the reciprocal stopping power gives

R(100\,\mathrm{MeV}) = 7.71\,\mathrm{g\,cm^{-2}}

and

R(200\,\mathrm{MeV}) = 25.95\,\mathrm{g\,cm^{-2}}

. The density of water is

1.00\,\mathrm{g\,cm^{-3}}

. ((a)) Use the

100\,\mathrm{MeV}

point to find

\alpha

, and check it against the

200\,\mathrm{MeV}

point. ((b)) Find the range in water of a

150\,\mathrm{MeV}

proton, in centimetres.

Related theory

Nuclear Physics

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