21-22 November, 2013 ASTRID2 Status Heine Dølrath Thomsen on behalf of the ASTRID2 Team præsen TATION
ASTRID2 ASTRID2 is the new synchrotron light source being commissioned in Aarhus, Denmark ASTRID2 main parameters: Electron energy 580 MeV Emittance Beam Current Circumference Lattice 12 nm 200 ma 45.7 m 6 x DBA, combined func. dipoles 4 straight sections for insertion devices ASTRID as booster (full energy injection) Allows top-up operation Should be automatic only 2 accelerator physicists! 2
ASTRID2 Layout 3
ASTRID2 Status 90 ma steady-state top-up Problem with bumpers limits continuous top-up operation with higher currents Sep. 13: 200 ma held for 20 min of topup This week: alignment (GEOs3D) Beam lines: May 2013: First light in a beam line 5 beam lines are being installed Sep. 2013: Local test experiments performed with the AU-UV beam line (UV absorption and CD) Dec. 2013: Friendly users 4
ASTRID2 Cavity 105 MHz (like ASTRID), h = 16 Basically the same as MAX IV cavities Built by RI (RF design by MaxLab) Conditioned to ~80 kv (~900 W) No problems seen Will eventually condition to higher voltages 315 MHz Landau cavity ordered (from RI & based on MaxLab design). Delivery spring 2014 (expected) 5
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Compensation of IDs Compensate tune and beta beat with global tune correction and local beta correction using pole-face windings. y [m] 25 20 15 10 5 0 0 5 10 15 20 25 30 35 40 45 s - position [m] Insertion devices modeled as a long purely vertically focusing element (matrix) no insertions, Qh=5.185, Qv=2.14 MPW, no correction, Qh=5.185, Qv=2.1967 MPW, tune and betabeat reduc, 7
ASTRID2 dynamic aperture Dynamic aperture Matlab AT toolbox. 0.025 0.02 0.015 Ver. [m] 0.01 0.005 0-0.05-0.04-0.03-0.02-0.01 0 0.01 0.02 0.03 Hor [m] 8 no insertions, Qh=5.185, Qv=2.14 MPW, no correction, Qh=5.185, Qv=2.1967 MPW tune+beta corr Qh=5 1888 Qv=2 1391
Unexpected Problems Injection bumpers are getting excessively warm at high beam currents due to beam-induced RF heating Magnetic stray field from nearby booster (ASTRID) affects ASTRID2 beam orbit.... 9
Injection Bumpers v.1 10
Injection Bumpers v.1 Simple and cheap design (in-vacuum ferrite) no beam screen! Beam-induced RF heating of the bumper ferrite (T Curie ~ 130 C) First version: Beam current limited to 60 ma injection becomes inefficient 11
Injection Bumpers v.2 Shields with RF fingers added at ends + cooling of ground conductor Beam current limited to ~90 ma (+50%)! Cooling water off: 85 ma achieved. Inefficient cooling Why? 12
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Injection Bumpers v.3? Cooling inefficiency should be assessed Add beam screen (cut foils, wires) along the ferrites How thick? Possible to cut foils into wires? Input + ideas are welcome! 14
Time-varying Orbit Displacement A2 BPM Time 15
Magnetic Stray Field From Booster Effect reduced by AMO ID! 16
Conclusion & Status Nominal beam current has been reached (for limited periods) Ready for users, but still have a big job to characterize and understand ASTRID2 Retrofitting bumpers to limit beam-induced heating v. 3? Landau cavity in spring 2014 ID has been moved from ASTRID -> ASTRID2: 3 IDs installed! Existing beam lines being moved to ASTRID2 Plans to change microtron filament to increase top-up stability, (Dirk Schüler, HZB) Shielding: limit radiation in adjacent, unrelated labs to < 0.3 msv / y. 17 IR beam line? Generous users with 85 k! Visits to ANKA-IR 1