The Canadian Light Source (CLS) conducts a Call for Proposals twice per year, accepting proposals for peer-reviewed access to beamtime in the upcoming 6-month cycle.

Cycle Scheduling Period Call Open Call Close PRC Meeting (Week of) Results Announced (Week of)
37 Jan-June, 2023 July 27, 2022 Aug 24, 2022 Oct 24, 2022 Nov 7, 2022
36 July-Dec, 2022 Jan 26, 2022 Feb 23, 2022 April 25, 2022 May 9, 2022
35 Jan-June, 2022 July 28, 2021 Aug 25, 2021 Oct 18, 2021 Nov 1, 2021
34 July-Dec, 2021 Jan 27, 2021 Feb 24, 2021 April 19, 2021 May 3, 2021

The Basics

Beamtime is access to a CLS beamline. Beamtime is allocated to users in shifts. One shift is 8 hours of beamtime. The CLS runs 24 hours a day, so beamtime can begin at 8AM, 4PM, or midnight.

Facility operations are scheduled in 6-month cycles. The facility operations schedule defines when the facility is open to user experiments (normal beamtime), shut down for maintenance, or in development mode (where maintenance and improvements to the linear accelerator and storage ring can be performed).

Users can access beamtime through a number of different mechanisms, including Peer-Reviewed Access, Puchased Access, Rapid Access, and Beamteam Access.

COVID-19 Rapid Access

In an effort to help fight this global pandemic, the CLS is offering a special call for proposals for any work that will actively contribute to finding COVID-related treatments or vaccines, or improve conditions for frontline workers, including developing sensors and diagnostic tools or special surfaces with antiviral properties.

Learn more about how to apply, and some of the exciting research that has already been facilitated through this program. 

Peer-Reviewed Access

Proposals for General User beamtime are submitted through the Call for Proposals, which is a competitive peer review process, twice per year, emphasizing the excellence of science where there is intent to publish scientific results. The CLS allocates and schedules the research time on all beamlines. 


Both Macromolecular Crystallography (MX) users and General Users (GU) should submit proposals for beamtime during an open Call for Proposals. A successful proposal results in a CLS project that is active for two years.

Beamtime Requests / Shift Requests

Beamtime requests for GU access can be submitted against active projects during subsequent Calls for Proposals. 

Shift requests for MX access can be submitted against active projects at least two weeks prior to the requested beamtime, even outside of a Call for Proposals.

APS Access: Requesting beamtime for access to CLS@APS beamlines must follow CLS@APS procedures and respect APS proposal deadlines. Due to the APS Upgrade, scheduled to begin April 17, 2023, CLS@APS proposals will not be accepted for Cycle 37. Beamtime requests may still be submitted for active CLS@APS projects per the APS beamtime request process. For inquiries regarding your beamtime request submission, please contact CLS@APS beamline scientist Debora Meira.


An access fee of $1 per eight hour shift and fees for other items such as materials, supplies, and/or shipping/receiving of samples and products are invoiced to the user.

Peer Review Process  How to Submit a Proposal

Purchased Access

Purchased Access is available through our Industrial Science program, a service group providing the mechanisms for researchers to do rapid access, proprietary and/or full service synchrotron measurements.

Industry Services

Rapid Access

Special requests for rapid access allow users to access beamtime outside our usual peer-review cycles, based on the beamline availability, and is awarded to projects needing beamtime very soon. Examples of urgency include, but are not limited to: high profile work in danger of losing out to international competition or critical time-limited work for inclusion in a graduate student's thesis. Any successful project will be limited to six months from the approval’s day and future access should be through the General User Access process. There must be an intent to publish via this mechanism.

Letters of Intent can also take advantage of rapid access to beamtime, providing the opportunity to perform exploratory experiments as a beamline is being commissioned. Research must be discussed with the appropriate CLS Beamline Responsible to confirm feasibility and timeframe prior to submitting an application. Letters of Intent are accepted throughout the commissioning phase by submitting a Rapid Access proposal.

Internal Review Process

The Science Director approves all Rapid Access proposals prior to the experiment being performed. It is required that you contact the appropriate CLS Beamline Responsible prior to submitting your proposal to discuss the feasibility of your research activity, and beamline availability. 


An access fee of $1 per eight hour shift and fees for other items such as materials, supplies, and/or shipping/receiving of samples and products are invoiced to the user.

How to Submit a Proposal

Beamteam Access

A Beamline Advisory Team (Beamteam) is a group of scientists dedicated to research which involves the use and application of the beamline sector with which they are associated. The Canadian Light Source  operates all facilities at the CLS, and the Beamteam provides expertise and advice to the CLS regarding beamline design, operations, and enhancement. The CLS acknowledges the role that the scientific leadership and expertise of Beamteams has played, and continues to play, in the development of the CLS. 

The amount of beamtime allocated to Beamteam members, if applicable, is defined in the Beamline Team Memorandum of Understanding (MOU) with CLSI for each beamline. Priority Access will be an allocation of beamtime to Beamteam members according to the internal agreement of Beamteam. The Beamteam will satisfy CLSI that there is an accepted method of allocation of this time among the Beamline Team dedicated to research involving the use and application of the beamlines.


Proposal submissions are accepted throughout the year, but must be received a minimum of four weeks prior to your desired experiment date for the necessary safety, technical, and ethics (if required) reviews. All proposals must be approved prior to performing the experiment. Beamteam members submit proposals via the User Portal, selecting Beam Team as the proposal type.


An access fee of $1 per eight hour shift and fees for other items such as materials, supplies, and/or shipping/receiving of samples and products are invoiced to the user.

Beamline Advisory Teams  How to Submit a Proposal