C.Limborg-Deprey Beam Dynamics Justifying L01 [email protected] November 3 rd 2004 Beam Dynamics Justifications of modification of.

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

Beam Dynamics Justifications of modification of

Linac structuresC.Limborg-Deprey

Parameter goals for the LCLS injectorDipole moment

in L01 in L02

Quadrupole moment

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

Gun S1 S2 L0-119.8MV/m

L0-224 MV/m

‘Laser Heater’

6 MeV = 1.6 m ,un. = 3keV

63 MeV = 1.08 m ,un. = 3keV

135 MeV = 1.07 m ,un. = 3keV

DL1

135 MeV = 1.07 m ,un. = 40keV

Lina

c tu

nnel

UV Laser 200 J,

= 255 nm, 10ps, r = 1.2 mm

Peak Current 100 A

Charge 1 nC

projected,slice 1.2,1 m.rad

Repetition rate 120 Hz

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

Nominal tuning – Q = 1nC,10psNominal tuning – Q = 1nC,10psthth = 0.72 mm.mrad, r = 0.72 mm.mrad, rlaserlaser = 1.2 mm = 1.2 mm

Solenoid 1 0.3% gun 2.5

Solenoid 2 20% Linac Field 12 %

(EFinal = 150 MeV )

Egun 0.5%

Balance~ 3% is ok

Errrors

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

Combination of errors

Using extreme values of parameters deviations meeting regulation specifications

Design for 1nC operation even if other operating points are being investigated

Using extreme values of parameters deviations meeting regulation specifications

Design for 1nC operation even if other operating points are being investigated

Param. Nom. Units Stability Requirement

Sol1 2.7235 kG 0.02 %

Sol2 0.748 kG 1 %

Gun

Phase

27.25 /0-X 0.1

Gun Field 120 MV/m 0.5%

Charge 1 nC 5%

L01Field 18 MV/m 2.5%

2^6 possibilities = 64 2^6 possibilities = 64 runsruns

Cannot afford additional emittance growth

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

S-Band linac structure

Correction of amplitude term with offset of cell

No correction of phase term

See J.Schmerge talk

and Blue Book P 147, P191

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

L01 entrance coupler

Dipole time dependent head-tail kick, integrated over the entrance cell and two first full cell (see Z.Li’s talk)

10ps bunch, Phase = close to crest , 18MV/m

() 2.5.10-3

increase

with = rms of head-tail kick

o

twiss

o

2

1

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

L01 entrance coupler

Crest = 0

Max – min for a 10 ps long bunch

Rms a 10 ps long bunch

a 10 ps long bunch

Vrf = 18 MV/m

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

L01 coupler

PARMELA simulations of misalignment including transverse wakefield show similar magnitude

200 rad = 2.4.10-3

4% increase

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

L01 exit coupler

The emittance growth will not exceed 1% at the exit of L01

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

L02 entrance coupler

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

L02 exit coupler

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

Quadrupole moment

Quadrupole moment in L01 entrance

0.0200.20Cross Dual

0.0040.04Race-track dual

0.0630.63Symmetric dual

0.0780.78SLAC Single feed

Head-tail angle (rad/m)

()/m

0.0200.20Cross Dual

0.0040.04Race-track dual

0.0630.63Symmetric dual

0.0780.78SLAC Single feed

Head-tail angle (rad/m)

()/m

for 10 ps

Dual feed

C.Limborg-Deprey

Beam Dynamics Justifying L01 modifications [email protected]

November 3rd 2004

Conclusion

Dual Feed mandatory for both L01 and L02 input couplers

output couplers do not absolutely require dual feed

Racetrack shape of entrance cell is mandatory for both L01 and L02