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

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Review of Detector Solenoid Effect to the Beam Effect on Beam Orbit Effect on Beam Size S.Kuroda(KEK) Slide 2 Solenoid Effect on Beam Orbit Sharp edge approximation Finite crossing angle with offset L c [email protected] 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] Slide 3 Correction of the Orbit Offset 2 correctors K1= /(1-L1/L2) ( inside sol.) K2= - /(L2/L1-1)( outside sol.) Extracted beam y=(2 + 1/(L2/L1 1)) [B.Parker, A.Seryi] Slide 4 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] Slide 5 Solenoid Effect on Beam Size Effect due to synchrotron radiation SR ~ (B 0 c L) 5/2 F(optics) [PRSTAB-061001] (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[ 0 2 + 2 ] Slide 6 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 Slide 7 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] Slide 8 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] Slide 9 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 Slide 10 Summary For non-zero x-ing angle, solenoid field will make finite y @IP 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 )