title: Beam based alignment and its relevance in Indus-2.
abstract: Initially in the Indus-2 storage ring, the closed orbit distortion (COD) could be best corrected to 1.3 mm rms in the horizontal and 0.43 mm rms in the vertical plane. The strength of the corrector magnets required high values for COD correction. This revealed that offsets in COD readout by the beam position monitors (BPMs) played a role in not achieving a rms COD lower than the above value. Thus, the offset between the electrical center of BPMs and the magnetic center of the nearest quadrupole magnet could be estimated using the beam based alignment (BBA) method. It prefers that the quadrupole magnet is able to be controlled individually and active shunt power supply (ASPS) system was designed for this purpose that works efficiently. This paper describes the methodology of BBA, topology of ASPS and its performance, and COD minimization using the measured BPM offsets. After BBA, the COD could be reduced to 0.45 mm rms and 0.2 mm rms in horizontal and vertical planes, respectively.
authors.affiliation: Raja Ramanna Centre for Advanced Technology, Indore, India.
authors.forename: Saroj Kumar
authors.initials: SK
authors.lastname: Jena
authors.affiliation: Raja Ramanna Centre for Advanced Technology, Indore, India.
authors.forename: Riyasat
authors.initials: R
authors.lastname: Husain
authors.affiliation: Raja Ramanna Centre for Advanced Technology, Indore, India.
authors.forename: M L
authors.initials: ML
authors.lastname: Gandhi
authors.affiliation: Raja Ramanna Centre for Advanced Technology, Indore, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Agrawal
authors.affiliation: Raja Ramanna Centre for Advanced Technology, Indore, India.
authors.forename: S
authors.initials: S
authors.lastname: Yadav
authors.affiliation: Raja Ramanna Centre for Advanced Technology, Indore, India.
authors.forename: A D
authors.initials: AD
authors.lastname: Ghodke