Girder Realignment using Survey and Beam Data M
Girder Re-alignment using Survey and Beam Data M. Apollonio – Diamond Light Source Ltd. Low Emittance Design Workshop, ALBA (Barcelona), April 24 th 2015 thanks to: M. Boge, R. Bartolini, R. Dowd, X. Huang, L. Nadolski, J. Safranek, … 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 1/28
Outline - Motivations Alignment techniques - Beam Based Alignment - Girder Alignment Quadrupole centring Sextupole centring ORM based techniques (LOCO) Survey Assisted (SAGA) Beam Assisted (BAGA) - Conclusions 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 2/28
motivations conclusions alignment techniques Why aligning the machine? - a perfectly aligned machine ensures nominal performance - first requirement to get nominal photon beam properties - orbit distortions minimized via orbit corrections - CMs correct orbit but introduce dispersion in both planes - Orbit is zero at BPMs / can be ≠ 0 anywhere else - misalignments after installation or growing in time require corrections, otherwise: - orbit distortions - dispersion (emittance increase) - tune shifts / beta-beating - linear coupling - non linear resonances - dynamic & momentum aperture issues - mis-alignment with photon beamlines 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 3/28
motivations conclusions alignment techniques Further alignment can be necessary after installation Usually rely on Beam Based Techniques: - BPM / quadrupole centring (BBA) [or sextupole centring] - Diamond, SLS, ASLS, SPEARIII … - BPM rolls - Diamond, SLS, ASLS, … - Individual magnet alignment - ASLS, … - Girder Based Alignment - Diamond, SLS, ASLS, SOLEIL, … 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 4/28
motivations conclusions dipole alignment techniques quadrupole BBA Quadrupole centring (BBA) BPM quad corrector • scan quad gradient • if orbit moves, beam is not at centre of quad • change upstream corrector(s) to change position of the beam in quad • the zero of the adjacent BPM is re-defined when orbit does not move anymore • orbit correction will put the beam at the (magnetic) centre of the quad • crucial at commissioning (+LOCO, +Orbit Corrections) • routinely repeated over the ring @ every run (~ each month) • aimed at few BPMs if recently “touched” 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 5/28
motivations conclusions alignment techniques quadrupole BBA Quadrupole centring (BBA) BBA offsets @ SPEAR III : < 700 um quadcenter. m G. Portman et al. Reproducibility: 25 um after 38 d [MATLAB middlelayer] Courtesy J. Safranek SPEARIII commissioning / 2004 24/04/2015 SPEARIII M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 6/28
motivations conclusions alignment techniques quadrupole BBA BPM reading @ 5 CM settings = 5 positions of the beam inside QUAD Quadrupole centring (BBA) quadcenter. m [MATLAB middlelayer] Diamond Orbit change from: Q+d / Q-d Data filtering: outliers removal (e. g. small slope. . . ) Centre of QUAD from fit 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 7/28
alignment techniques quadrupole BBA motivations conclusions BBA offsets (Diamond Commissioning, 2006 c. ca)BBA offsets (Diamond 20/3/2015) Large Offsets: - BPM electrical centres not calibrated - Not accurate mech. survey Smaller offsets Diamond Reproducibility & general issues ~ few 10 um in adjacent runs >few 100 um if BPM has been worked on Current Dependence of BPM response Heat load on chamber Primary BPMs: different geometry 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 8/28
alignment techniques motivations quadrupole BBA conclusions 2 m stability BBA offsets @ SLS : <500 um Reproducibility: <50 um after 2 m 50 um SLS -50 um BBA actual offsets Courtesy M. Boge 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 9/28
alignment techniques quadrupole BBA motivations conclusions BBA offsets @ SLS : <500 um Reproducibility: <50 um after 2 m BBA offsets correlation to mechanical displacement SLS Courtesy M. Boge 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 10/28
motivations conclusions alignment techniques sextupole alignment from ORM [APS] Orbit deliberately sent off axis at sextupoles to comply with users golden orbit. APS Need to know the offset at sextupoles. LOCO approach extended by defining “virtual” quads and skews at sextupole locations: - quadrupole fits the H offset @ sextupole: Kquad = (x-x 0) K 2 - skew-quad fits the V offset @ sextupole: Kskew = -(y-y 0) K 2 V. Sajaev et al. / Proc. IPAC 10, Procedure: THPE 091 • scan sextupole by family (S 1 – S 4) • measure ORM • fit the quadrupole and skew quadrupole component • linear fit on the gradient to find the H and V offsets at the sextupoles further developed @ ASLS 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) Courtesy V. Sajaev 11/28
motivations conclusions alignment techniques sextupole alignment from ORM [ASLS] Clean linear machine (LOCO). Main target is the V offset in sextupoles individually to reduce the V emittance. Instrumental in achieving the quantum limit 0. 35 pm ASLS V offsets used to shim each individual magnet on the girder (sextupoles found systematically lower vertically). Shim units of 25 um, max shim reached ~ 150 um in many cases R. Dowd et al. / Proc. IPAC 13, TUPWA 003 24/04/2015 Courtesy R. Dowd M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 12/28
alignment techniques sextupole alignment from ORM [ASLS] motivations conclusions Shimming sextupoles for V alignment at ASLS Courtesy R. Dowd 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 13/28
alignment techniques quadrupole rolls from ORM [ASLS] motivations conclusions Kskew = sin(q/2) K 1 ramp sextupoles down to zero gradient (!) ASLS Vary K 1 and measure ORM LOCO find Kskew infer qquad Define girder roll as average of qquad Roll girders to reduce coupling Courtesy R. Dowd 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 14/28
alignment techniques survey data for girders [SLS] motivations conclusions SLS found (2010) quadrupole misalignments are dominated by girder misalignments (correlation in offset of individual quads on the girder) SLS Offsets w. r. t. girder line M. Aiba et al. / Nuclear Instruments and Methods in Physics Research A 694 (2012) 133 – 139 Fit to individual positions 24/04/2015 magnet M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 15/28
alignment techniques survey data for girders [Diamond] motivations conclusions Diamond: large girder misalignments both in the H and V plane Survey August 2013 H-plane Survey January - August 2013 V-plane Diamond best fit plane 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 16/28
alignment techniques survey data for girders [Diamond] motivations conclusions Diamond Survey August 2014 V-plane d Z +600 um - 600 um S Smoothing line 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 17/28
motivations conclusions alignment techniques survey data for girders [SPEARIII] SPEARIII Courtesy J. Safranek Smooth Curve (SC): - badly mis-aligned magnets individually re-aligned wrt SC (~every yr) - beam-lines follow the re-alignment - recent re-alignment (summer 2014): - easy injection - CM corrector reduction - skew quad strengths reduced 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 18/28
alignment techniques girder displacements vs correctors [SLS] motivations conclusions SLS observed a characteristic pattern in correctors adjacent to misaligned girders. Misalignments cause: V dispersions and orbit distortions SLS Courtesy M. Boege 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 19/28
motivations conclusions alignment techniques girder concept [SLS] SLS Courtesy M. Boege 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 20/28
motivations conclusions alignment techniques Beam Assisted Girder Alignment [SLS] -girders moved according to heave/pitch fits from quad survey data -FOFB on and beam in the SR SLS -Actual girder move inferred from CM variations (online) BAGA M. Boege et al. / Proc. IAPC 13, WEPME 047 -Procedure “refined” with final quad-BBA Before BAGA After BAGA Courtesy M. Boege 24/04/2015 Girder realignment instrumental in reducing the vertical ey down to 0. 9 pm. New BAGA campaign foreseen based on 2013 survey data M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 21/28
motivations conclusions alignment techniques Beam Assisted Girder Alignment [SLS] SLS Courtesy M. Boege 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 22/28
alignment techniques girder concept [SOLEIL] motivations conclusions -56 girders, each equipped with a 3 -pot HLS system to monitor long term vertical variations SOLEIL - plan to lower coupling for users vertical re-alignment under discussion (for 2015) - no sextupole re-alignment so far 3 HLS Courtesy L. Nadolski 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 23/28
motivations conclusions alignment techniques girder concept [Diamond] 24 cells x 3 girders + 2 girders (mini-beta sections) = 74 girders LVDT motion sensors bellow @ G 2 – G 3 Diamond LVDT motion sensors bellow @ G 3 end 1 st motion attempt in a mock-cell !! Camshaft Bearing CAM motors Axes of rotation 24/04/2015 Range of motion M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 24/28
motivations conclusions alignment techniques girder alignment [Diamond] Initial tests with single girder moves … VC 8 G 2 heave=+197 um Diamond Survey Assisted Girder Alignment SAGA CM variation correctly reproduced when BBA corrections are introduced in the model (as done in the machine) 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 25/28
motivations conclusions alignment techniques transparent re-alignment [Diamond] - Diamond is a densely populated environment - leading idea: re-align SR with no impact on operating beamlines - orbit variations compensated by Golden Offsets at primary BPMs - initial single girder tests - now remotely controlled system (a la SLS) for multi-girder moves 4, 5 & via 6 Golden equipped and TR at BL-I 05: BBA (1) and(cells orbit restoration commissioned) Offset (2) Diamond ID 05 -239 um (1) (2) VC 4 G 2+G 3 heave G 2= -275 um G 3 = -250 um 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 26/28
alignment techniques transparent re-alignment [Diamond] motivations conclusions TR at BLI 05 0) initial configuration C 4 8/4/2015 - C 5 G 1 G 2 moved - BBA - Remove all GOs - Re-align beamline 19/12/2014 - C 4 G 2 G 3 moved - BBA - GO transparent to BL C 4 C 5 C 5 Significant VCM reduction BBA offsets (4 cycles) o machine model move+BBA beamline re-aligned: all GOs = 0 Very good agreement GO(4, 7)=239 um M. Apollonio - Low Emittance Lattice Model vs Machine 24/04/2015 Design ALBA (Barcelona) 27/28
motivations conclusions alignment techniques A collection of tools for beam based alignment is available and has been well tested at several different light sources ORM technique at ASLS shows that sextupole horiz. and vert. offsets can be measured with beam to an accuracy of 10 -50 um depending on magnet location. Together with quadrupole roll measurement and girder roll correction, this was instrumental to reduce ey (~quantum limit) Girder alignment with remote control proven at SLS (important to reduce vertical emittance to 9 pm). Encouraging results being obtained at Diamond. Beam based alignment techniques can potentially achieve measurements of the magnetic centre of magnets to precision comparable to the best bench-top techniques 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 28/28
Thanks for your attention. . . 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) 29/28
SPARES alignment techniques orbit cross-talk: LOCO [Diamond] LOCO: off diagonal sector of the ORM to fit a number of machine parameters such BPM gains and coupling. Inclusive measurement of BPM mechanical rolls and electrical cross talk between the X and Y electronics channels BPM rolls from LOCO @ Diamond Courtesy R. Bartolini 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) Spares-1
alignment techniques orbit cross talk [SLS] SPARES conclusions Similar analysis based on in-house software. Measured via corrector pattern analysis: exciting V orbit bumps at each BPM and measuring H correctors BPM rolls from Orbit cross-talk @ SLS Dispersion function looks more like a betatron wave after cross talk correction Results cross checked with LOCO Courtesy M. Boge 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) Spares-2
alignment techniques transparent re-alignment [Diamond] SPARES conclusions TR at BL-I 05 (19122014): effect of orbit tilt on I 05 energy peaks (SHADOW simulation) 24/04/2015 M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) Diamond Spares-3
SPARES conclusions TR at BLI 05 alignment techniques transparent re-alignment [Diamond] A) Before move E = 62. 913 e. V Gau. B width = 4. 665 me. V 0) initial configuration B) After move+BBA E = 62. 915 e. V DE = +2 me. V Gau. B width = 5. 124 me. V 1) move + BBA C) Orbit re-stored inside ID 05 GO(4, 7) = 239 um E = 62. 913 e. V DE = 0 me. V Gau. B width = 4. 523 me. V 2) Set GO bump restore initial orbit 24/04/2015 He energy peak @ I 05 Perfectly restored M. Apollonio - Low Emittance Lattice Design ALBA (Barcelona) Pares-4
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