• R. Bartolini, C. Christou, J.H. Han, I.P.S. Martin, J. Rowland
  Diamond, Oxfordshire
• D. Angal-Kalinin, F. Jackson, B.D. Muratori, P.H. Williams
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire

Several new light source projects aim at the production of X-ray photons with high repetition rate (1kHz or above). We present here the results of the start-to-end simulations of a 2.2 GeV superconducting LINAC based on L-band SC Tesla-type RF cavities and the corresponding optimisation of the FEL dynamics at 1 keV photon energy.

• P.H. Williams, D. Angal-Kalinin, J.K. Jones, B.D. Muratori, S.L. Smith
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• R. Bartolini
  JAI, Oxford
• I.P.S. Martin, J. Rowland
  Diamond, Oxfordshire
• H.L. Owen
  UMAN, Manchester
• P.H. Williams
  Cockcroft Institute, Warrington, Cheshire

A design for a free electron laser driver which utilises 1.3 GHz superconducting CW accelerating structures is studied. The machine will deliver longitudinally compressed electron bunches with repetition rates of 1 kHz with a possibility to increase up to 1 MHz. Tracking is performed from an NC RF photocathode gun, accelerating and compressing in three stages to obtain peak current greater than 1 kA at 2.2 GeV. This is achieved through injection at 200 MeV, then recirculating twice in a 1 GeV main linac. The optics design, optimisation procedures and start to end modelling of this system are presented.

• R.P. Walker, R. Bartolini, C. Christou, J.H. Han, J. Kay, I.P.S. Martin, G. Rehm, J. Rowland
  Diamond, Oxfordshire
• D. Angal-Kalinin, M.A. Bowler, J.A. Clarke, D.J. Dunning, B.D. Fell, A.R. Goulden, F. Jackson, S.P. Jamison, J.K. Jones, K.B. Marinov, P.A. McIntosh, J.W. McKenzie, B.L. Militsyn, A.J. Moss, B.D. Muratori, S.M. Pattalwar, M.W. Poole, R.J. Smith, S.L. Smith, N. Thompson, P.H. Williams
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• N. Bliss, G.P. Diakun, M.D. Roper
  STFC/DL, Daresbury, Warrington, Cheshire
• J.L. Collier, C.A. Froud, G.J. Hirst, E. Springate
  STFC/RAL, Chilton, Didcot, Oxon
• J.P. Marangos, J.W.G. Tisch
  Imperial College of Science and Technology, Department of Physics, London
• B.W.J. McNeil
  USTRAT/SUPA, Glasgow
• H.L. Owen
  UMAN, Manchester

The New Light Source (NLS) project was launched in April 2008 by the UK Science and Technology Facilities Council (STFC) to consider the scientific case and develop a conceptual design for a possible next generation light source based on a combination of advanced conventional laser and free-electron laser sources. Following a series of workshops and a period of scientific consultation, the science case was approved in October 2008 and the go-ahead given to continue the project to the design stage. In November the decision was taken that the facility will be based on cw superconducting technology in order to provide the best match to the scientific objectives. In this paper we present the source requirements, both for baseline operation and with possible upgrades, and the current status of the design of the accelerator driver and free-electron laser sources to meet those requirements.

• J. Rowland, I.P.S. Martin
  Diamond, Oxfordshire

The study of nonlinear effects in storage rings requires massively parallel particle tracking over a range of initial conditions. Stream processing architectures trade cache size for greatly increased floating point throughput in the case of regular memory access patterns. The symplectic integrator of Tracy-II* has been implemented in CUDA** on the nVidia stream processor and used to calculate dynamic apertures and frequency maps for the Diamond low-alpha lattice. To facilitate integration with existing workflows the the lattice description of Accelerator Toolbox*** is re-used. The new code is demonstrated to achieve a two orders of magnitude increase in tracking speed over a single CPU core and benchmarks of the performance and accuracy against other codes are presented.

*J. Bengtsson, Tracy-2 User's Manual, Feb 1997.
**NVIDIA, NVIDIA_CUDA_Programming_Guide_1.1.pdf
***A. Terebilo - ACCELERATOR MODELING WITH MATLAB ACCELERATOR TOOLBOX, PAC 2001

• I.P.S. Martin, J. Rowland, B. Singh, C.A. Thomas
  Diamond, Oxfordshire
• R. Bartolini, I.P.S. Martin
  JAI, Oxford

With the aim of generating short pulse radiation, a low momentum compaction lattice has recently been commissioned for the Diamond storage ring. By introducing both positive and negative dispersion in the bending magnets it has been possible to operate the storage ring in a quasi-isochronous state, resulting in a natural electron bunch length of less than 1 pico-second. A description of the techniques used to develop the lattice is given, along with first results obtained during recent machine trials. Operation with both positive and negative momentum compaction factor is also described

• B. Singh, R.T. Fielder, E.C. Longhi, I.P.S. Martin, C. Rau, U.H. Wagner
  Diamond, Oxfordshire
• R. Bartolini
  JAI, Oxford

A proposal has been developed to modify a long insertion straight (~11.4 m long) of the DIAMOND storage ring. Additional quadrupoles provide two sections with small vertical beta-function values, in order to accommodate two canted in-vacuum undulators for the imaging and coherence branches of the I13 beam line. A further requirement was to provide a horizontal focussing of the emitted undulator radiation by means of a positive alpha-x in the second section. This optic is obtained using a small relaxation in the “pi–trick”, approximately preserving the on-momentum nonlinear dynamics of the ring. The effects of the optic on beam dynamics (i.e. beam lifetime, injection etc.) and possible compensation schemes are presented.

• I.P.S. Martin, J. Rowland, B. Singh, C.A. Thomas
  Diamond, Oxfordshire
• R. Bartolini, I.P.S. Martin
  JAI, Oxford

With the aim of generating short pulse radiation, a low momentum compaction lattice has recently been commissioned for the Diamond storage ring. By introducing both positive and negative dispersion in the bending magnets it has been possible to operate the storage ring in a quasi-isochronous state, resulting in a natural electron bunch length of less than 1 pico-second. A description of the techniques used to develop the lattice is given, along with first results obtained during recent machine trials. Operation with both positive and negative momentum compaction factor is also described