Longitudinal calculations cheat sheet
Relativistic relationships
- Mass energy
E0=m0c2
- Total energy
E=Ekin+E0
- Momentum
E=(pc)2+E02
p=γm0βc
- Relativistic velocity
β=cv=Epc=1−γ21
- Lorentz factor
γ=E0E=1−β21
- Differential relationships
pdp=β21EdE=γ2βdβ
Machine parameters
- Magnetic rigidity
Bρ=qp
- Revolution period/frequency
T=v2πR=f1=ω2π
- RF period/frequency
frf=hf=2πωrf=Trf1
- Linear momentum compaction factor (and transition factor)
αc=Δp/pΔR/R=γt21
- Linear phase slippage factor
η=Δp/pΔT/T=−Δp/pΔf/f=αc−γ21
- Other useful relationship
p=ωβ2E
Longitudinal equations of motion
- Equation of motion 1 - Phase slippage (drift) along the ring (continuous)
dtdϕ=pRhηω(ωΔE)=β2Ehηω2(ωΔE)
- Equation of motion 2 - Energy kick with single RF cavity (continuous)
dtd(ωE)=2πqV(sinϕ−sinϕs)
- Equation of motion 1 - Phase slippage (drift) along the ring
Δtn+1=Δtn+βs2Esη0TrevΔEn
- Equation of motion 2 - Energy kick in cavity
ΔEn+1=ΔEn+qVsin(ωrfΔtn)−(Esn+1−Esn)
- Beam energy gain per turn
(Esn+1−Esn)=qVsinϕs
Bucket parameters and synchrotron motion
- Bucket height
ΔEmax=βπh∣η∣2qVEY(ϕs)
- Bucket height reduction factor
Y(ϕs)=cosϕs−2π−2ϕssinϕs1/2
- Bucket area
Abk=16ωrfβ2πh∣η∣qVEα(ϕs)
- Bucket area reduction factor
α(ϕs)≈1+sinϕs1−sinϕs
- Angular synchrotron frequency (small amplitudes)
Ωs2=2πfs=−ω22πβ2EhηqVcosϕs
- Non-linear synchrotron frequency for a maximum amplitude in phase ϕu
ΩsΩ(ϕu)≈1−16ϕu2
- Synchrotron tune
Qs=ωΩs
Differential relationships
C. Bovet et al., A selection of formulae and data useful for the design of A.G. synchrotrons, CERN-MPS-SI-Int-DL-70-4
Variables |
Equations |
B,p,R |
pdp=γt2RdR+BdB
|
f,p,R |
pdp=γ2fdf+γ2RdR
|
B,f,p |
BdB=γt2fdf+γ2γ2−γt2pdp
|
B,f,R |
BdB=γ2fdf+(γ2−γt2)RdR
|