醫學物理學與輻射安全題庫下載題庫

Particle

Expression

Mass (amu)

Charge

Property

Proton

p

1.007277

+1

Neutron

n

1.008665

0

Electron

e^- or β^-

0.000548

-1

Positron

e⁺ orβ⁺

0.000548

+1

Photon or γ-ray

Hνorγ

0

0

Neutrino

ν_e

1/1800 m_e

0

ν_e + p⁺ → n +β⁺

Mu-mesons

↓

μ⁺

207 m_e

+1

μ⁺ → e⁺ + 2ν_e

μ^-

207 m_e

-1

μ^- → e⁺ + 2ν_e

Mean life = 2.15×10^-6 sec

Pi-mesons

↓

π⁺

273 m_e

+1

π⁺ →μ⁺ +ν_e

π^-

273 m_e

-1

π^- →μ^- +ν_e

π⁰

265 m_e

0

π⁰ →hν₁ + hν₂

Mean life：π⁺ &π^- = 2.5×10^-8 sec；π⁰ = 10^-15 sec