Septum Magnets in Hall A Hall A Collaboration Meeting 6/10-11/2010 John J. LeRose

Septum Magnets with Spectrometers 101 Fixed Pivot

Septum Magnets with Spectrometers 101 Fixed Pivot

Septum Magnets with Spectrometers 101 To change angles you must change 2 things and not just any 2 things e.g.Septum and spectrometer position Target position and septum bend angle …

Central angle ≈ 8° It doesn’t work!

Present Septum Magnets Super Conducting: – Off the table for now because of Qweak PREX: – In the Hall and working now (see PREX status) No problems magnetically! – Limited field capability P max ≈ ° (more with booster pump) – Same angle both arms – Same polarity both arms easy to switch to opposite polarities, but there are beam steering issues!

In the Physics Storage building Installed in the Hall

Future Septa For g2p PREX with auxiliary coils – Field quality not as good as for PREX but still acceptable with software corrections Pmax ≈ ° – Presently we have some acceptance issues we’re working through Hypernuclear (just an idea now) – Two separate RT magnets One for 5° electron arm (low field fewer/smaller coils) (½ PREX) One for 8° and 11° kaon arm (higher field larger coils, but further from the beamline) (½ g2p)

Proposed g2p Septum

Conclusion We have had good luck making a room temperature coil septum magnet – PREX: good optics, very high luminosity, inexpensive (~$187k) For g2p modifications to the PREX magnet are relatively simple (extra coils) For Hypernuclear we hope we can reuse much of the PREX magnet (at least the coils)