Tuning and Alignment of the ATF2 Anthony Scarfe Christmas Meeting 20-12-07 – 21-12-07

Reintroduction Based at the Cockcroft Institute Supervisor: Rob Appleby PhD Project Title: Tuning and Alignment for ATF2 and ILC Second Year

Current Progress Dimad (particle tracking code) interface for Mathematica Orbit correction optimisation for ATF2 Final Focus Sextupole-based R-matrix tuning knob optimisation for ATF2 Final Focus Bump-emittance experiments at ATF (with Rob Appleby)

ATF2 ATF2 is a test accelerator in KEK, Japan. It can achieve the same low emittances needed for ILC. The Final Focus is the last section of the machine

Tuning and Alignment This is very important, the machine will not work without tuning. Step 1 – Orbit Correction: The path of the beam is recorded by beam position monitors and is altered by correcting magnets. A tracking code like Dimad is used to find the relations between each monitor and each corrector. Matrix manipulation techniques are used to calculate the corrector strengths needed to change the recorded path into the design path. The corrector strengths are applied to the machine. This is very important, the machine will not work without tuning. I’m working on 3 different sets of matrix manipulation techniques for the sextupole-based tuning knobs: Traditional Method – uses the in-depth optics knowledge to work out what the required matrices are. R-matrix method – uses information of the particle positions/motions to work out what the required matrices are. D.U.M.B method – uses brute force to work out what the required matrices are. This is very important, the machine will not work without tuning. Step 2 – Dispersion and Coupling Correction: The beam will have coupling between the horizontal and vertical planes and will suffer from dispersion, which leads to emittance growth, which leads to bigger beamsizes and lower luminosities. These are corrected in a lot of different ways, one way to correct them is to use a set of sextupoles, an in-depth understanding of the optics of the machine and a set of matrix manipulation techniques to work out how to alter the positions, orientations and strengths of the sextupoles to correct the dispersion and coupling. The matrix manipulation techniques are called tuning knobs. The optimisation of the orbit correction and tuning knobs of a machine involves the optimisation of the matrix manipulation techniques.

Future Plans The optimisation of the traditional and D.U.M.B tuning knobs for ATF2 The optimisation of the orbit correction and all 3 tuning knobs for ILC Implementation of the developed techniques on ATF2 when it is finished next year More bump-emittance studies