9 Accelerator Operations
551
a maximum local cleaning inefficiency max[ ˜
η c ] over all critical locations. For
example, in a super-conducting storage ring max[ ˜
η c ] describes the peak loss per
m in super-conducting magnets. Alternatively, in a linac max[ ˜
η c ] may describe the
peak loss per m in the regions that must be protected for hands-on maintenance.
During the design phase one should define an allowable maximum beam loss rate
R lim for critical locations. The maximum allowed loss rate R loss at the collimators is
defined in particles per second. It depends on the allowable maximum beam loss rate
R lim for critical locations and the maximum local inefficiency of the system [76]:
R loss =
R lim
max[ ˜
η c ]
.
(9.63)
The loss rates R loss can be converted into energy deposition rate P loss using:
P loss =
R loss
(p/s)
·
E b
(GeV)
· 1.6022 × 10
−10 W .
(9.64)
Considering a stored beam and assuming that all leaked particles are lost at
collimators we can relate R loss = to the number of particles N max and
beam lifetime τ min :
τ min = −
T
ln
1 −
R loss ·T
N max
≈
N max
R loss
.
(9.65)
For convenience we give the equation for calculating the energy deposition rate for
any lifetime:
P loss ≈ N max ·
(h)
τ min
·
E b
(GeV)
· 4.45 × 10
−17 kW .
(9.66)
The maximum achievable beam intensity can be expressed as a function of the
maximum local cleaning inefficiency, the minimum beam lifetime that must be
sustained and the limit of beam loss in critical regions [76]:
N max =
τ min · R lim
max[ ˜
η c ]
.
(9.67)
Similar equations can be given for single-pass accelerators. This equation can be
used during the design phase of an accelerator to specify the required collimation
performance once beam intensity, minimum beam lifetime and loss limits have been
determined. A proper design of a collimation system requires a well-defined target
for cleaning efficiency.
551
a maximum local cleaning inefficiency max[ ˜
η c ] over all critical locations. For
example, in a super-conducting storage ring max[ ˜
η c ] describes the peak loss per
m in super-conducting magnets. Alternatively, in a linac max[ ˜
η c ] may describe the
peak loss per m in the regions that must be protected for hands-on maintenance.
During the design phase one should define an allowable maximum beam loss rate
R lim for critical locations. The maximum allowed loss rate R loss at the collimators is
defined in particles per second. It depends on the allowable maximum beam loss rate
R lim for critical locations and the maximum local inefficiency of the system [76]:
R loss =
R lim
max[ ˜
η c ]
.
(9.63)
The loss rates R loss can be converted into energy deposition rate P loss using:
P loss =
R loss
(p/s)
·
E b
(GeV)
· 1.6022 × 10
−10 W .
(9.64)
Considering a stored beam and assuming that all leaked particles are lost at
collimators we can relate R loss = to the number of particles N max and
beam lifetime τ min :
τ min = −
T
ln
1 −
R loss ·T
N max
≈
N max
R loss
.
(9.65)
For convenience we give the equation for calculating the energy deposition rate for
any lifetime:
P loss ≈ N max ·
(h)
τ min
·
E b
(GeV)
· 4.45 × 10
−17 kW .
(9.66)
The maximum achievable beam intensity can be expressed as a function of the
maximum local cleaning inefficiency, the minimum beam lifetime that must be
sustained and the limit of beam loss in critical regions [76]:
N max =
τ min · R lim
max[ ˜
η c ]
.
(9.67)
Similar equations can be given for single-pass accelerators. This equation can be
used during the design phase of an accelerator to specify the required collimation
performance once beam intensity, minimum beam lifetime and loss limits have been
determined. A proper design of a collimation system requires a well-defined target
for cleaning efficiency.