SOLEIL Fast Orbit Feedback System First results and optimization Nicolas HUBERT Synchrotron SOLEIL On behalf of Diagnostics group 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA Summary System properties System efficiency What has to be done before using it in operation? 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA FOFB properties Modularity: choice in the number of involved BPMs (from 1 to 120) 2 configuration have been used: 48 BPMs (straight sections BPMs) 120 BPMs (all of them) Correction is applied at 10 KHz to 48 dedicated power-supplies and air-coil correctors (located at each side of the straight sections). For the moment the correction is done from DC, (SOFB system is OFF) Integrative coefficient of the PI controller is equal to 1: IN = ΔIN + IN-1 => simple accumulator 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA FOFB efficiency The frequency range were the FOFB has an influence can be divided in 3 area: 1 Hz to 500 Hz : fast beam perturbations 0.01 Hz to 1 Hz : Insertion devices perturbations DC to 0.01 Hz : slow drifts 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA FOFB efficiency (0-500 Hz) 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA FOFB efficiency (0-100 Hz) 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA Effect on the perturbations caused by the insertion devices (vertical plane) NO OFB SOFB FOFB 48*48 FOFB 120*48 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA FOFB efficiency on slow drifts Values in µm and µrad DESIRS (UV) Hard X ray Soft X ray Bending magnets sx /10 Dx pp (fofb off) 3.5h Dx pp (48x48) 2h Dx pp (120x48) 3h 32 12 18 10 0.5 39 15 0.3 ? 4.5 1.5 0.2 s'x /10 Dx’ pp (fb off) 3.5h Dx’ pp (48x48) 2h Dx’ pp (120x48) 3h 4.6 3.4 2.5 0.1 11 0.9 sz /10 Dz pp (fb off) 3.5h Dz pp (48x48) 2h Dz pp (120x48) 3h 6 4 0.6 6.5 5.8 0.55 3.2 17 4.1 s'z /10 Dz’ pp (fb off) 3.5h Dz’ pp (48x48) 2h Dz’ pp (120x48) 3h 4.2 1.6 0.52 5.3 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA Soleil particularity Slow correctors are located inside the sextupoles. Vacuum chambers are in Aluminum because of NEG coating => Necessity to have different correctors for the Fast Feedback (over stainless steel bellows) SOFB and FOFB systems are operating with different correctors 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA Should the FOFB correct to DC? Slow and Fast Feedback are not compatible at the moment Option 1: Make a dead-band to separate both system S O F B FOFB 0.1 1 10 100 Frequency (Hz) + Both systems are independent - Some perturbation caused by insertions will not be corrected Development of a high pass filter => Option 2: Make the FOFB efficient to DC FOFB 0.1 1 10 100 Frequency (Hz) Verification that the FOFB can work alone during at least 8 hours without saturation Elaboration of a communication between the 2 feedbacks External treatment of the correction applied on the RF + All low frequency perturbations can be damped - SOFB should from time to time relieve the fast correctors from their DC part. => 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA To be solved before operation Spikes on the correction: FOFB 48*48 FOFB 120*48 SOFB NO OFB Visible on both plane: 60 µm in horizontal 1 µm in vertical 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA Spikes 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA Spikes 3-4/04/2008 2nd Libera Users Meeting, ALBA

2nd Libera Users Meeting, ALBA Schedule Loop closed for the first time in December 2007 First use in operation foreseen for September 2008 Special thanks for their collaboration to I. Uzun and G. Rehm (Diamond Light source) E. Plouviez (ESRF) 3-4/04/2008 2nd Libera Users Meeting, ALBA