Multiple scattering in injection channel details
Site visit March 5, 2002
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overview
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accelerator physics
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wiggler
Dynamic aperture and tune scans (R.Helms)
Dynamic aperture is computed for 2,4,6,8,10,12, and 14 wigglers. Wiggler model is based on MERMAID calculation and tracking by runge_kutta integration. The lattice is bmad_rk_v_custom. There are also tune scans for linearized as well as MERMAID modelled wigglers. And calculation of tune shift vs oscillation amplitude and effect of correction with octupoles. helms ---------------------------------------------------
CBN 01-21
- Effects of Parasitic Crossings on Tunes (S.Buchan and D.Rubin)
- Calculation of dependence of
- tune
- beta*
- closed orbit
- on number of bunches, bunch current, for various 5.3, and 1.89GeV optics
Synchrotron radiation power density (7-dec-2001)
- Lattice : [cesr.2gev.rkwig]bmad_rk_v_custom_linear.
- Beam energy = 1.88 GeV.
- Pretzel is on
- Vertical emittance is 2nm.
- Beam current is 100mA/beam
- Wiggler period = ~40cm
- Wiggler B=2.1T
Lattice: bmad_dhrmove_v27.
Wiggler beta_x (m) pretzel (mm) nearest quad
1 15.5 7.5 Q13
2 18.3 13.4 Q13-Q14
3 24.8 15.6 Q14
4 6.4 5.9 Q15
5 26.4 -16.7 Q18
6 23.5 -14.5 Q18-Q19
7 16. -12.4 Q19
In this lattice the pretzel maximum is at the north end of Q18 which
is also the south end of wiggler #5. The next largest amplitude is
at the north end of Q14 which is about a meter from the north end
of wiggler #3. Without a redesign of the optics, the proposed 4mm mask
would limit pretzel amplitude.
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3-pole wiggler field measurements
The following plots show the integrated vertical field of the 7 pole wiggler vs x and the resulting horizontal kick to a 1.89 GeV beam. The average kick is zeroed. The fields are calculated with MERMAID. The "trimmed" field refers to an attempt to adjust trim windings on the poles to reduce horizontal dependence, and evidently not quite right.
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beta_orbit closed orbit, beta and eta for BMAD_DHRMOVE_V27. - 14 wiggler, 1.88GeV lattice, B_cleo = 1T
beta_cbar beta and cbar in IR for BMAD_DHRMOVE_V27. - 14 wiggler, 1.88GeV lattice, B_cleo = 1T
Round beam optics and aperture
Tune scans with and without wigglers
Machine sudies
- This lattice is designed for better separation in IR.
- Crossing angle is about 2.6mrad
- Beta_h ~ 0.6m