Chapters 1-8

Most common source for fast electrons?

radioisotope that decays by beta-minus emission

What mechanism determines probability of heavy nuclei decay? (alpha)

barrier penetration mechanism

Most common calibration source for alphas?

Am-241

Correlation between alpha energy and parent half-life?

Higher alpha energy, shorter parent half-life

Why can’t bremsstrahlung be used for calibration?

Bremsstrahlung spectra are continua

E and Z dependeance on Brem production?

higher Z of absorbing material and higher electron energy will increase brem production

What gives the maximum k-series photon?

when vacancy is filled by unbound electron

Why k-series are most practically significant? (over L or M)

Higher energy

What is fluorescent yield?

fraction of all cases in which the excited atom emits a characteristic x-ray in de-excitation

Why is source thickness important when considering consistent measurements?

Self absorption increases with increasing source thickness

How does charactersitic x-ray energy change with Z?

Higher Z, higher characteristic x-rays

What is max energy that can be transferred from charged particle (mass, m; energy, E), to an electron (mass, m_o)?

4Em_o/m ~ 1/500 particle energy per nucleon

What causes Bragg peak?

charge on particle is reduced through electron pickup → less reactions and energy dump

cutoff energy between fast and slow neutrons?

0.5 eV (Cadmium cutoff energy)

typical energy of thermal neutrons? (room temp)

0.025 eV

Difference between LET and Stopping power?

Stopping power (specific energy loss) includes Brem.. LET counts only energy deposited along track, locally

Difference between total equivalent dose (H_T, related to effective dose) and dose equivalent (H)?

H_T or effective dose is not a point quantity, an average/sum over all tissues/organs

ambient vs directional dose equivalents?

ambient is for monitoring strongly penetrating radiation. direction is for weakly penetratin

Difference between phosphorescence and delayed-fluorescence?

phosphorescence has a longer wavelength