Synchrotron radiation from 2mrad FD and backscattering from extraction line elements

1
Synchrotron radiation from 2mrad FD and
backscattering from extraction line elements

• T. Maruyama and A. Seryi

2
Backscattering
2mrad layout
Span of SR produced at downstream FD
3
SR generations
BYCHICMB
BYCHICB
ONE 250 GeV e-
QD0
These photons hit the septum.
y (cm)
From BYCHICB
x (cm)
4
250 GeV disrupted beam
Total Power 2.5 kW
20
Total photons 1.0x1011 / BX
From QF1
15
photons x108/mm/BX
Power (W/mm)
10
Mostly from QD0
5
0
x (cm)
x (cm)
5
250GeV/beam undisrupted beam
Turtle tracking Analytical SR Ec MATLAB
Seryi
Total loss ltdE/Egt0.0011578 or ltdEgt12.7356
kW Total loss to septum ltdEgt2.8275 kW , mean
Ec21.9458 MeV
6
SR rate at the septum
SR Energy dist.
500 GeV g/e- 10.1
250 GeV g/e- 5.2
TM disrupted beam
log10(Eg (GeV))
Ng B Ec Eb2 x B
AS disrupted beam
AS undisrupted beam
7
SR backscattering to IP

• To estimate the photon flux within 2 cm BeamCal
  aperture.
• Find the backscattering rate in -1 lt cos? lt -0.9
• Use the solid angle of the 2 cm aperture from z
  89m.

g
250 GeV
Back scatt. prob. 19.9
Prob/0.02
cosq
8
Conclusions

• SR power at the septum magnet is 2.5 kW _at_ 250 GeV
  and 40.6 kW _at_ 500 GeV.
• Backscattered photon flux at IP is 2200/BX _at_ 250
  GeV and 11700/BX _at_500 GeV.
• The IP photon flux is x3 (250 GeV) and x6 (500
  GeV) of the secondary photons from pairs.