The Linac Coherent Light Source (LCLS) Protein Crystal Screening (PCS) program will dedicate shifts at the CXI instrument during Run 9, April – July 2014. PCS proposals must be submitted by October 22 to be considered for beam time starting in spring of 2014.

The LCLS PCS program aims to enable new users to get their first access to LCLS beam time for biological structure determination and also to allow testing samples in preparation of a full LCLS proposal. Successful PCS proposals are expected to receive short allocations of beam time, limited to 6 hours.

To enable measurements within such a short time frame and maximize the chances of success and efficiency, these studies must be carried out with limited flexibility to minimize the time impact of setup changes. Currently, gas dynamic virtual nozzle (GDVN) experiments are possible at CXI and several possibilities for fixed targets can be explored within CXI. All PCS experiments are currently carried out inside the standard CXI vacuum setup using the 1um or 100nm focus and CSPAD detectors.
Time-resolved studies and spectroscopy are currently not within the possible scope of PCS beam time. We will carefully consider any proposed alternative setup allowing screening within the 6 hour time frame to extend the accessibility. Such alternative setups include all kinds of liquid jet modifications and sample mounting options, as long as such setups are available and have been demonstrated to work at the time of scheduling. The decision on whether a proposed alternative setup can be supported within the PCS program will be entirely at the discretion of LCLS staff scientists involved in the PCS program.

PCS proposals are submitted independently of regular LCLS proposals, and there are no restrictions with regard to the scope and/or possible overlap or redundancy with regular LCLS proposals. If the PCS proposal is related to one or more regular LCLS proposals that have been previously submitted or already received beam time, the team must state this in the proposal. PCS proposals will be reviewed by the PRP BIO panel separately from regular proposals.

PCS proposals are limited to a two-page PDF, including references and figures. PCS proposals must provide sufficient information to evaluate the impact, originality, need for LCLS, scientific risk, as well as technical feasibility. LCLS PCS proposals should be submitted through the user portal available here. PCS proposals will follow a similar format as regular proposals. The two-page PDF proposal should include a descriptive title of the proposed experiment that can be made public if beam time is awarded, and a brief abstract. All proposal team members should be identified. In the safety management portion, identify safety concerns that may arise with samples, procedures or equipment, e.g. any physical, chemical or biological hazards, and how these issues will be addressed in the experiment design.

Researchers interested in submitting PCS proposals for the CXI instrument should contact LCLS-CXI Scientist Marc Messerschmidt (mcmesser@SLAC.Stanford.EDU).

The proposal process and guidelines are described at the LCLS website.

LCLS PCS proposals must be submitted before 4 PM (Pacific) on Tuesday, October 22, 2013.