Physics and Engineering of Radiation Detection

136 Chapter 2. Interaction of Radiation with Matter

Silicon

Aluminum

Analytic Function

Figure 2.5.7: Variation of elec-

tron range ing/cm^2 with energy

in MeV computed from the

equations 2.5.28. Also shown

are the ESTAR values for alu-

minum and silicon.

Solution:

We use equation 2.5.28 to compute the specific range of 5MeVelectrons.

Rspe =5. 30 E− 1. 06

=5. 30 × 5 − 1. 06

=25. 44 kgm−^2

=2. 544 gcm−^2

The range of electrons in aluminum is then simply determined by dividing this

number with the density of aluminum.

Re =

Rspe

ρ

=

2. 544

2. 699

=0. 94 cm

Hence it will take less than 1cmthick slab of aluminum to completely stop

β-particles having an endpoint energy of 5MeV.