particle physics Flashcards
equation to find neutron number (N) of nucleus?
N = A - Z
where A = nucleon or mass number and Z = proton or atomic number
equation for energy of particle (E rest) when v «_space;c using particle’s rest mass (m0)? (m0, c)
E rest = m0(c^2)
equation for energy of particle (E total) at relativistic speeds (where v ≈ c)? (γ, m0, c)
E total = γm0(c^2)
where γ = lorentz factor, m0 = rest mass and c = speed of light
equation for lorentz factor (γ)? (E total, E rest)
γ = E total/E rest
(E total = rest E + KE)
equation for energy of particles (E) when particles have VERY high energies? (p, c)
E ≈ pc
(E = pc is true for photons)
equation for energy of particles (E)? (p, m)
E = (p^2)/2m
equation for total (KE + PE) energy (E n) electron requires to be liberated from energy level n? (n, E1)
E n = (1/n^2)E1
where n = energy level number and E1 = energy of initial level
equation to calculate angle (θ) of diffraction to first minima (first dark fringe) when diffracting nuclei? (λ, d)
sinθ = 1.22λ/d
equation to work out radius of whole nucleus (R)? (r0, A)
R = r0(A^1/3)
where r0 = radius of proton (1.05 fm or 1.5 x 1E-15) and A = nucleon number
representation of alpha decay?
atom -> diff atom (with 2 less protons and neutrons) + helium nucleus (2 protons, 2 neutrons)
representation of gamma decay?
atom* -> same atom + γ
representation of beta minus decay?
atom with neutron -> new atom where neutron changed to proton (so same nucleon number but +1 proton for proton number) + electron + antielectron neutrino
(need to release antielectron neutrino to conserve lepton number)
representation of beta plus decay?
atom w proton -> new atom where proton changed to neutron (same nucleon number but -1 proton for proton number) + positron + electron neutrino
(need to release electron neutrino to conserve lepton number)
equation for attenuation of radiation (I)? (I0, µ, x)
I = I0(e^-µx)
where I = intentisty, I0 = initial intensity, µ = linear absorption or attenuation coefficient and x = material thickness
equation for half-value thickness (x 1/2)? (like half-life)
x 1/2 = ln2/µ
where x 1/2 = half-value thickness (for particular material, thickness need to half intensity of radiation), µ = linear absorption or attenuation coefficient
equation for absorbed dose (D)?
D = E/m
where E = energy absorbed and m = mass
equation for equivalent dose (H)?
H = D x Q
or
H = EQ/m
where D = absorbed dose and Q = quality factor
what is quality factor (Q) for photons, etc?
- photons, all energies: Q =1
what is quality factor (Q) for electrons + muons, etc?
electrons + muons, all energies: Q =1
what is quality factor (Q) for high E neutrons?
high energy neutrons: Q = 10
what is quality factor (Q) for high E protons?
high energy protons: Q = 10
what is quality factor (Q) for α particles + other atomic nuclei?
alpha particles + other atomic nuclei: Q = 20
equation for binding energy (ΔE)? (m, c)
ΔE = Δm(c^2)
where Δm = difference between sum of masses of individual nucleons + mass of nucleus
(binding energy is given as negative, bc energy is put IN)
absorption cross section?
absorption cross section = πd^2
where d = diameter of particle
(acs is the distance another particle must pass within to collide with a particle)
