Review of Detector Solenoid Effect to the Beam Effect on Beam Orbit Effect on Beam Size S.Kuroda(KEK)

Solenoid Effect on Beam Orbit Sharp edge approximation Finite crossing angle with offset L  c   y=0  y’=-  : No effect on Luminosity for e+e-, but need compensation for e-e- Need compensation for post IP polarimetry  =B0  c/(2 B  )  y’= -2  for extracted beam must be also considered in extraction line design. [B.Parker, A.Seryi]

Correction of the Orbit Offset 2 correctors K1=  /(1-L1/L2) ( inside sol.) K2= -  /(L2/L1-1)( outside sol.) Extracted beam  y’=−Θ(2 + 1/(L2/L1 − 1)) [B.Parker, A.Seryi]

Detector Integrated Dipole(DID) Real solenoid field extends and overlaps to FD. Correction by FD offset  Large orbit distortion  Correction should be done locally(y changes inside solenoid)  DID DID: Co-winding with solenoid in cryostat 1. Smaller B  radiation Length in detector  acceptance 2. Avoiding torque(forces) between solenoid and B when B is introduced separately. 3. Large bore  good uniformity in beam region DID+FD offset  IP angle compensation [B.Parker]

Solenoid Effect on Beam Size Effect due to synchrotron radiation  SR ~ (B 0  c L) 5/2 F(optics) [PRSTAB ] (independent on beam energy) for  c =20mrad full x-ing angle:  SR = 0.31 nm in SD  SR = 0.57 nm in LD  where  is understood as  =sqrt[   2 ]

Overlapping effect of Bz to FD 1.Real solenoid field extends and overlaps to FD  Beam size growth 2. Independent on  c  LD Bz profile LD model,  = 20 mradLD model,  = 0 [Y.Nosochkov, A.Seryi] green:no solenoid red:with solenoid

Beam size compensation  Correction can be done using skew Q & SX displacement   y/  y0~1.03 This correction method is difficult when E is very low. SiD case only orbit cor. Beam size cor. by SQ,SX… [B.Parker, A.Seryi]

Example of LD solenoid compensation using two weak antisolenoids (2.26 and 0.07 Tm) placed at two FF quads. Total field with and w/o antisolenoids IP phase space with antisolenoid correction,  y = 23% With antisolenoids and linear knobs,  y = 0.9% [Y.Nosochkov, A.Seryi]

IP distortion & beam size compensation for SiD (DID & anti-solenoid)  Additional B BXMID introduced Beam size is corrected to  y/  y0~1.01 by anti-solenoid and skew Q  Knob strength is relaxed by anti-solenoid

Summary For non-zero x-ing angle, solenoid field will make finite  y’ should be zeroed for e-e- collision/post IP polarimetry A corrector in solenoid region is needed( e.g. DID ) Beam size growth due to overlapping solenoid field to FD ( indep. on x-ing angle ) >> Beam size growth due to synchrotron rad. Anti-solenoid method excellently compensates this effect ( down to low E )