, UKNF Meetin, Imperial College J. Pasternak Status and Recent Progress in the Muon FFAG Designs J. Pasternak, Imperial College, London / RAL STFC Work in collaboration and with contributions from: M. Aslaninejad (IC), J. Scott Berg (BNL), D. Kelliher (ASTeC/STFC/RAL), S. Machida (ASTeC/STFC/RAL), Y. Mori (Kyoto University), T. Planche (Kyoto University), H. Witte (JAI)

, UKNF Meetin, Imperial College J. Pasternak Outline of the talk Status of baseline IDS FFAG design (S. Berg, S. Machida). Studies of injection/extraction for IDS muon FFAG (D. Kelliher, J.P., M. Aslaninejad, H. Witte). Scaling FFAG options for low energy acceleration (Y. Mori, T. Planche). Summary and future plans.

, UKNF Meetin, Imperial College J. Pasternak Reference IDS Neutrino Factory Design nsFFAG

, UKNF Meetin, Imperial College J. Pasternak Introduction Motivations for Non Scaling FFAGs as muon accelerators: quasi-isochronous –enables high frequency RF linear fields – gives huge DA and allows for simple magnets small orbit excursion – cost effective Main problems: TOF with amplitude beam loading (not so much, see Juergen’s talk) injection/extraction Lattice choice FODO: cost-effective, allows for symmetric injection/extraction, but short drift good performance Triplet: more difficult, allows for symmetric injection/extraction, but longer drift! Old lattice parameters used in injection/extracion studies

, UKNF Meetin, Imperial College J. Pasternak Recent update of NS-FFAG parameters, J. Scott Berg

, UKNF Meetin, Imperial College J. Pasternak It will be tested in EMMA soon, 2010!

, UKNF Meetin, Imperial College J. Pasternak Alternative solution Nonliner NS-FFAG, S. Machida (1) Due to natural chromaticity time of flight depends on amplitude, which introduces longitudinal blow-up and limits acceptance. The lattice with chromaticity correction is proposed to correct for this effect. Natural chromaticity Corrected chromaticity, study by S. Machida

, UKNF Meetin, Imperial College J. Pasternak Alternative solution - Nonliner NS-FFAG, S. Machida (2) Layout of FFAG with insertions Please see S. Machida’s talk for updates.

, UKNF Meetin, Imperial College J. Pasternak Introduction to injection/extraction Working assumptions: Try to distribute kickers to reduce their strengths. Apply mirror symmetric solution to reuse kickers for both signs of muons. FDFFFDD Septum Positive Muons Negative Muons Septum Kickers

, UKNF Meetin, Imperial College J. Pasternak Main Magnets Kickers 0.1 T, 1.4 m Circulating 25 GeV Beam, 3 cm emittance Septum, 4 T, 1.4 m Extraction from FODO ring No satisfactory solution was found in horizontal plane The scheme using vertical plane requires special magnets Symmetric for both signs. Twiss functions in FODO at extraction

, UKNF Meetin, Imperial College J. Pasternak Injection - Triplet Kickers Septum Horizontal scheme is feasible in trilet. Scheme is less demanding with respect to special magnet needs. It uses m long kickers at T and the 2.4 m long septum at 2 T. Please see D. Kelliher’s talk for updates.

, UKNF Meetin, Imperial College J. Pasternak Effects of special magnets Beams close to septum push the magnet aperture. Special magnets with higher aperture is needed in injection/extraction regions. Those magnets introduce the ring lattice symmetry breaking, which can cause accelerated orbit distortion. Current studies show that the effect is not dramatic, but more simulations are needed.

, UKNF Meetin, Imperial College J. Pasternak Preliminary ideas for kicker R&D PS PFN switch Transmission line Kicker Termination 3 independent Pulse Forming Networks (PFNs) and switches are needed for every muon train. Termination is very important to avoid reflections back to magnet (for injection). Current is most likely to high for thyratrons, but IGBTs should be OK. We want to push conventional kickers, but may also look at new ideas. Kicker R&D are just starting for FFAG accelerators within IDS! FFAG IDS kicker: size HxV (~ 0.3 x~ 0.3 m), field 0.1 T, I~ 24 kA, V~28 kV, rise time 1.5 us length 1.4 m PAMELA-FFAG kicker: size HxV (~ x~0.026 m), field T, I~ 9 kA, V~50 kV rise time 100 ns length 1 m Work in collaboration with H. Witte.

, UKNF Meetin, Imperial College J. Pasternak What about the septum? Superconducting septum of similar parameters was designed and constructed for Jefferson Lab Hall A The very similar suptum is needed for medical FFAG for carbon treatment We are just starting the study in collaboration with JAI, Oxford.

, UKNF Meetin, Imperial College J. Pasternak Scaling FFAG lattices for muon acceleration, (Y. Mori, T. Planche)

, UKNF Meetin, Imperial College J. Pasternak Orbit excursion 20 cm Updated scaling FFAG lattice under development by T. Planche (with higher magnetic field and longer drift)!

, UKNF Meetin, Imperial College J. Pasternak Baseline NS linear FFAG lattices have been optimised. Alternative Nonlinear NS lattice with insertions and partial chromaticity correction was proposed. Injection/extraction schemes in the baseline lattices (FODO and triplet) were evaluated. The current results suggest triplet lattice to be easier (the baseline?). Scaling FFAG option for low energy muon acceleration ( GeV) compatible with 200 MHz RF was proposed. Work in progress on all aspects of muon FFAG towards the Fermilab IDS meeting! Summary