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A new strategic plan is in place to upgrade the ALS so it can continue to address fundamental questions, such as size-dependent and dimensional-confinement phenomena at the nanoscale; correlation and complexity in physical, biological, and environmental systems; and temporal evolution, assembly, dynamics and ultrafast phenomena. Moreover, the growing number of ALS users (now exceeding 2,000 per year) requires increased attention. Accordingly, our plan concentrates on projects that will continue to make it possible for ALS users to address grand scientific and technological challenges with incisive world-class tools and quality user support. Our highest priority is to begin top-off operation, in which electrons are injected into the storage ring at intervals of approximately 1 minute. The combination of top-off and concurrent development of small-gap in-vacuum undulators and superconducting undulators will allow an increase in brightness from eight to more than 100 times, depending on the specific undulators and photon energy range. As part of our core mission in the VUV and soft x-ray regions, we plan to exploit these accelerator developments to extend our capabilities for high spatial and temporal resolution and utilize the remarkable coherence properties of the ALS in a new generation of beamlines. Ranked by priority, several proposed beamlines will follow completion of five new beamlines already under construction or funded. The intellectual excitement of the ALS has been a powerful tool in the recruitment and retention of outstanding staff, but additional sustained efforts are required to increase diversity both in gender and in underrepresented groups. To this end, we intend to expand the ALS Doctoral Fellowship Program by giving special emphasis to underrepresented groups. We also envision a distinguished postdoctoral fellowship program with the same emphasis, to increase and diversify our pool of candidates for beamline scientist positions.

We present the concepts for an electron storage ring dedicated to and optimized for the production of stable coherent synchrotron radiation (CSR) over the far-infrared terahertz wavelength range from 200 mm to about one cm. CIRCE (Coherent InfraRed CEnter) will be a 66 m circumference ring located on top of the ALS booster synchrotron shielding tunnel and using the existing ALS injector. This location provides enough floor space for both the CIRCE ring, its required shielding, and numerous beamlines. We briefly outline a model for CSR emission in which a static bunch distortion induced by the synchrotron radiation field is used to significantly extend the stable CSR emission towards higher frequencies. This model has been verified with experimental CSR results. We present the calculated CIRCE photon flux where a gain of 6 - 9 orders of magnitude is shown compared to existing far-IR sources. Additionally, the particular design of the dipole vacuum chamber has been optimized to allow an excellent transmission of these far-infrared wavelengths. We believe that the CIRCE source can be constructed for a modest cost.

We present the concepts for a storage ring dedicated to and optimized for the production of stable coherent synchrotron radiation (CSR) over the far-infrar ed wavelength range from about 200 microns to 1 mm.

A variety of insertion devices (IDs), wigglers and undulators, linearly or elliptically polarized,are widely used as high brightness radiation sources at the modern light source rings. Long and high-field wigglers have also been proposed as the main source of radiation damping at next generation damping rings. As a result, it becomes increasingly important to understand the impact of IDs on the charged particle dynamics in the storage ring. In this paper, we report our recent development of a general explicit symplectic model for IDs with the paraxial ray approximation. High-order explicit symplectic integrators are developed to study real-world insertion devices with a number of wiggler harmonics and arbitrary polarizations.

We derive second and higher order explicit symplectic integrators for the charged particle motion in an s-dependent magnetic field with the paraxial approximation. The Hamiltonian of such a system takes the form of $H = \sum_k(p_k-a_k(\vec{q},s))^2 + V(\vec{q},s)$. This work solves a long-standing problem for modeling $s$-dependent magnetic elements. Important applications of this work include the studies of the charged particle dynamics in a storage ring with strong field wigglers, arbitrarily polarized insertion devices,and super-conducting magnets with strong fringe fields. Consequently, this work will have a significant impact on the optimal use of the above magnetic devices in the light source rings as well as in next generation linear collider damping rings.