Dose 2016

Energy dependence at low photon energies (photon interactions in the detector medium)

Energy absorption coefficient ( μ en

/ ρ ) ratios, norm. at 1 MeV

100

Max ratio ~115 at 40 keV

=47

Z

Ag

Film (Ag based)

Silicon (Diode)

Air (Ion chamber)

10

Film (Nylon based)

Max ratio ~8 at 30 keV

Carbon (Diamond)

Medium / Water Z Si

=14

Isooctane (LIC)

1

Max ratio ~1.1 at 30 keV

0.01

0.10

1.00

10.00

(Air) ≈ 7.6

Z

eff

(water) ≈ 7.4

Z

eff

Min ratio ~0.33 at 15 keV

(Isooctane) ≈ 5.4

Z

eff

0.1

Photon energy (MeV)