Accelerator Design

The Group has led the design of several low energy ion storage rings and has been involved in the optimization of several beam transport lines and linear accelerators.

The Ultra-low energy electrostatic Storage Ring (USR) at the future Facility for Low-energy Antiproton and Ion Research (FLAIR) was designed to provide cooled beams of antiprotons in the energy range between 300 keV down to 20 keV and possibly less. Detailed investigations of the USR, including studies into the ring’s long term beam dynamics, life time, equilibrium momentum spread and equilibrium lateral spread during collisions with an internal target were carried out. New tools and beam handling techniques for diagnostics of ultra-low energy ions at beam intensities less than 106 were developed by the QUASAR Group.

In addition, we have designed a very compact electrostatic ‘recycler’ ring, and associated electrostatic injection beamlines. The ring may be used for a variety of experiments using a choice of many types of recirculating ions (e.g., from protons, H-, and antiprotons up to and including large charged biomolecules).

Finally, the Group is contributing to the design of ELENA, a compact ring for cooling and further deceleration of 5.3 MeV antiprotons delivered by the CERN Antiproton Decelerator. With a circumference of about 30 m, ELENA can be located in the AD hall where assembly and commissioning would not disturb the current AD operation. Decelerating to these low energies is new and will be very challenging both in the design of the different elements and for the operation of the ring. We are carrying out beam dynamics and lifetime studies into the ELENA ring and beam lines.


Currently involved QUASARs:



Selected publications:


'Beam life time studies and design optimization of the Ultra-low energy Storage Ring', C. P.Welsch, A. I. Papash, J. Harasimowicz, O. Karamyshev, G. A. Karamysheva, D. Newton, M. Panniello, M. Putignano, M. R. F. Siggel-King, A. Smirnov, Hyperfine Interactions, DOI 10.1007/s10751-014-1063-2 (2014).

'Ultra-low energy storage ring at FLAIR', C. P. Welsch,  A. I. Papash. O. Gorda,  J. Harasimowicz, O. Karamyshev, G. Karamysheva, D. Newton, M. Panniello, M. Putignano, M. R. F. Siggel-King, A. Smirnov, Hyperfine Interact (2012).

'Design of the injector for a small recycling ring on the CERN-AD', O. Karamyshev, G. Karamysheva, A. Papash, M. R. F. Siggel-King, C. P. Welsch, Nucl. Instr. Meth. A vol 700 pp 182-187 (2012).

'Study of slow and fast extraction for the ultralow energy storage ring (USR)'. G. Karamysheva, A.I. Papash, C.P. Welsch
Part. Phys. Nucl. Let. 8 p.50-60 (2011).

'Realization of Nanosecond Antiproton Pulses in the Ultra-low Energy Storage Ring', A. Papash, C.P. Welsch, Nucl. Instr. and Meth. A 620 (2011).

'Electrostatic ultra-low-energy antiproton recycling ring', M.R.F. Siggel-King, A.I. Papash, H. Knudsen, M. Holzscheiter and C.P. Welsch, Hyperfine Interactions 199 (2011).