June has been a very busy month. The annual Users' Executive Committee (UEC) meeting kicked things off on the evening of June 6th with the CHESS Users' Meeting following quickly the next day (read about it in last month's eNewsletter here
). On June 8th and 9th, CHESS hosted the first three of six science workshops exploring the science that will be enabled by the CHESS-U upgrade. (Find three workshop summaries below, and three to follow next month.) The following week contained both the 4th science workshop and the CHESS-U Machine Advisory Committee's (MAC) review of the CHESS-U accelerator design. The panel found that, "The overall plan and design of the CHESS lattice upgrade is in very good shape for the critical path components (i.e. lattice and magnets)," and congratulated CHESS on "success in building momentum for approval and funding of the upgrade." The MAC concluded that the CHESS-U design's ribbon-shaped beams and ability to support high (>65nC) bunch charges of CHESS-U create unique capabilities for hard x-ray imaging and timing experiments. The 5th and 6th Science Workshops were held the following two weeks. During this entire period, CHESS provided continuous x-ray user operations.
While x-ray user operations have ceased for the summer, July is turning out to be just as busy. The CHESS Scientists, Science Workshop Organizers, UEC, and External Advisory Committee (EAC) have begun a series of meetings to distill the output from the six workshops to create a Science Case Document for a modern 3rd generation high-energy synchrotron source. This Science Case will be completed in early September and will be both mail and panel reviewed by the National Science Foundation.
Just last week, CHESS-U took its first dramatic, visible steps as the riggers carefully unstacked and then removed the massive, blue, heavy-concrete shielding blocks which have protected users for many years. They're clearing the path required to remove the particle physics detector (CLEO). During this summer down, we will carefully open up the storage ring (CESR), remove and disassemble CLEO, and the ship the CLEO magnet to Jefferson Laboratory. We'll then reassemble CESR and recommission everything for x-ray operations for the fall user run which begins in late October.
During the fall of 2016, in collaboration with the user community, we will design x-ray beamlines that enable the science outlined in the Science Case. In parallel with the accelerator components, the x-ray beamlines will be procured, assembled and tested off-line. During the summer 2017 down period, we plan to re-locate the klystrons which provide the RF power to CESR into the (former) CLEO pit.
Then, in the summer of 2018, we will convert the south arc of CESR to a double bend achromat (DBA) lattice that provides straight sections for up to 10 insertion devices. CHESS-U will operate at an energy of 6-GeV with a stored beam current of 200 mA to produce X-rays up to high energy (order 100 keV) for in situ and operando studies. Operating with a single beam instead of with counter-rotating electron and positron beams will eliminate many of the performance limitations associated with the present 2-beam operation.
All-in-all this is an ambitious and aggressive schedule but, in typical CHESS fashion, we're excited to take on the challenge to achieve huge performance gains while still delivering all the x-ray running days our community needs. On to a brighter future for CHESS and its user community.