1 June 2026

The Facility for Rare Isotope Beams (FRIB) is a U.S. Department of Energy (DOE) Office of Science (SC) User Facility, open to all interested researchers, subject to applicable laws and regulations. Beam time for non-proprietary experiments is granted based on a merit review of written proposals describing the proposed work. User fees are not charged for non-proprietary work if the user intends to publish the research results in the open literature. Full cost recovery is required for proprietary work¹.

With this call, we invite proposals for beam time to be considered at the fourth meeting of the FRIB Program Advisory Committee (PAC4) on 1-2 December 2026. All proposals for review by FRIB PAC4 need to be submitted online by 11 pm EDT on 9 September 2026 to allow for scientific and technical review of the proposals prior to the PAC4 meeting. Requests for secondary-beam-rate calculations should be submitted by 27 July 2026.

FRIB PAC4 will consider proposals for experiments using fast, stopped and reaccelerated rare-isotope beams from the FRIB linac. Newly offered for PAC4:

• Additional primary beams from the FRIB linac and increased primary beam intensity (see the FRIB beams page); 
• New instrument: Gamma-Ray Energy Tracking Array (GRETA) offered in both the S800 and ReA6 experimental areas;
• Clarification of the role of the Contact Spokesperson, and new role of the Scientific Spokesperson;
• A new experiment category is being offered – Opportunistic irradiations: These are short runs of <6 hours beam time per irradiation that irradiate material in ARIS, including a solid or liquid stopper, and utilize a fragment beam that is used for another experiment. Such short irradiations carry no primary or secondary beam tuning overhead and will at most involve an ARIS rigidity adjustment. Such runs can only be scheduled opportunistically together with an approved, main FRIB experiment that happens to use the desired fragment beam or cocktail. Typically, very close coordination with the facility is required, in terms of irradiation modalities and comportment with requirements arising from the NRC license. The total number of hours for opportunistic irradiations will be limited to less than 5% of the total awarded time for PAC4.
• The team of co-spokespersons of PAC1-PAC3 experiments that received beam time before the PAC4 submission deadline are required to submit a 1-page update on the status of the completed experiment. This can be as short as a reference of a publication or present the status of the results towards publication. Information on how the experiment, so far, has advanced workforce development is welcome. These brief status reports will be made in the PAC Book and made available to the PAC members together with the proposals. 

Please review the Instruments in Operation page for a list of experimental areas and instruments that are available at FRIB. In preparation of proposals, all users are expected to follow the FRIB Research Code of Conduct.

Members of the FRIB PAC are listed on the Program Advisory Committee page. The contents of this Call for Proposals can be found on the Call for Proposals for PAC Period 4 for Non-Proprietary Research page.

¹ science.osti.gov/User-Facilities/Policies-and-Processes/Definition

Timeline for FRIB PAC4

The FRIB Scientific Director, Alexandra Gade, is the non-voting PAC convener and the Manager for User Relations, Jill Berryman, is the PAC administrator. 

Clarification of the role of the Contact Spokesperson, and new role of the Scientific Spokesperson

All communication from FRIB will go through the Contact Spokesperson. The Contact Spokesperson must be a scientist that assumes the responsibility to assure the funding and workforce required to mount, run, and analyze the experiment, and publish the results if the proposal is approved. This role cannot be assumed by a student or postdoctoral research associate.

The Scientific Spokesperson is responsible for the articulation of the science case and the realization of the experiment to address the science goals and can be any level of scientist, including students and postdoctoral research associates. The Contact Spokesperson can fulfill both roles if desired. 

Beam information

The FRIB PAC4 beams page provides:

• available FRIB primary beams
• estimates for rare isotope beam rates 
• beam list for stand-alone operation at ReA3, ReA6, or the stopped beam area

FRIB Rare Isotope Scientists will assist in calculation of beam rates and purities and will need to validate any assumed rare isotope beam rates prior to proposal submission. Once you have decided on an isotope of interest for the proposal, please contact Jill Berryman, Manager for User Relations, to be assigned a Rare Isotope Scientist Contact. The Rare Isotope Scientist Contact will help you with the detailed calculation of the beam(s) you wish to propose for your experiment. The deadline for making your request is 27 July 2026. FRIB rare isotope scientists strive for a two-week response time for requests.

Workforce development

The proposal form includes a required section on Workforce Development. A knowledgeable and well-trained workforce is essential to the DOE mission to ensure America's security and prosperity by addressing its energy, environmental and nuclear challenges through transformative science and technology solutions². If your experiment will be part of a thesis experiment or postdoctoral research project, describe what part of the proposed measurement is important for workforce development. Please also describe any efforts related to this proposal that support a skilled workforce and create a welcoming and respectful research environment.

² www.energy.gov/mission

Collaboration organization 

The proposal form includes a required section on Collaboration Organization. Please provide a brief statement on collaboration organization that addresses the following points:

• Responsibilities of participants, 
• How conflicts will be resolved, 
• How the collaboration will interface with FRIB. 

The PAC will use this information to assess how likely the collaboration will be able to carry out the proposed work.  Examples of what could be used for this section are available on the Collaboration Organization Guidelines page.

The collaboration organization is advised to discuss data management and sharing. FRIB has established a Data Management and Sharing Plan to address the regulatory standards pertaining to FRIB’s obligations to comport with

• The Special Terms and Conditions of the Cooperative Agreement between the U.S. Department of Energy Office of Science (DOE-SC) and Michigan State University (MSU) to operate FRIB as a DOE-SC user facility (DE-SC0023633 FA RD Special TC FEB 2026), which implement the 
• DOE-SC user facility policy, and the
• DOE Public Access Plan (June 2023), and the
• DOE Requirements and Guidance for Digital Research Data Management (2025)

A DMSP for the experiment must be in place upon accepting beam time (see link).

Submitting your proposal

The contact spokesperson of the experiment must register on the FRIB User Portal to start their proposal. After registering, navigate to the Proposal Application. The Proposal Application will walk the contact spokesperson through all of the necessary information, including: 

• title and summary
  • Can specify if the proposal has applied interest (for example, isotope production, stockpile stewardship, radiation effects, nuclear energy applications) and/or can specify that the proposal would benefit from a PAC reviewer familiar with and cleared to discuss measurements relevant to the NNSA mission
• contact spokesperson and scientific spokesperson (see above)
• co-spokespeople, experiment participants, and theorists
  • All participants must be registered in the FRIB User Portal prior to being added to the proposal and must have a complete profile. Users must enter a digital persistent identifier (PID)/ORCID iD in order to have a complete profile.
  • Co-spokespeople may edit the proposal as well as the contact spokesperson.
• beam type, location/beamline, instruments
• scheduling information
• special requests
• status of previous experiments at FRIB
• workforce development (see above)
• collaboration organization (see above)
• beam parameter worksheets 
• instrument worksheets
• data acquisition and computing worksheet
• safety information 
• the proposal text

The proposal text, can be uploaded directly in the Proposal Application as a pdf. The proposal text should be no more than four 8.5x11 in pages, 10 pt Arial font, 1.5 spaced, 1” margins, with additional pages allowed for references, tables, and figures. Please include the following in the proposal text:

1. Scientific motivation
2. Specific goals of the proposed experiment
3. Experiment details
   1. what is to be measured;
   2. figure/diagram of experimental instrument;
   3. demonstration of technical feasibility of measurement (by simulation and/or reference to prior work);
   4. justification for beam on target time requested 
      1. counting rate estimates (including assumptions), expected statistics, and level of uncertainty in the final measurement;
      2. explanation of other time requested (include time for debugging the experimental setup, calibrations, any test runs, and any stable beam runs necessary for reference, etc.);
   5. an indication of present state of readiness of the experiment and an estimated earliest date for the run;
   6. a clear statement of any technical assistance (design, fabrication, installation, etc.) that may be requested from FRIB;
   7. list of items that would be brought to FRIB;

Proposal evaluation

The PAC evaluation is based on:

• The full scientific value of the proposed work
• The technical feasibility of the proposal
• The ability and past record of the collaboration to successfully conduct the proposed experiment, including the status of previously approved experiments at FRIB
• The ability and past record of the collaboration to publish results in a timely manner

A first and second specialist reviewer will be assigned to each proposal. There will be no oral presentations, but at the latest 10 days prior to the PAC4 meeting, the reviewers may submit questions to the spokespersons. The questions and responses will be made available to all PAC members. 

Based on its evaluation, the PAC will make recommendations for allocation of beam to the FRIB Laboratory Director. The FRIB Laboratory Director will decide what beam time is granted. Approximately 5 percent of beam time will be reserved for discretionary experiments. Approved proposals will be valid for a three-year period.

Technical review

Prior to the PAC meeting, technical experts (FRIB staff members) will review each proposal to assess its technical feasibility from the point of view of FRIB. Any issues identified in the technical review will be promptly communicated to the spokesperson of the proposal, and the issue(s) along with response(s) from the spokesperson will be distributed to the PAC. FRIB staff having access to pre-decisional proposals attest to disclose all actual, potential, or perceived conflicts of interest during the review.

Safety and compliance

FRIB users must perform their experiments safely and within the FRIB regulatory framework. To allow us to assess any hazards associated with the specific experimental set-up, the Safety Information Worksheet must be completed as part of the proposal package. FRIB safety experts will review all proposals upon receipt for safety issues. Any findings identified in the safety review will be promptly communicated to the spokesperson of the proposal, and the finding(s) along with response(s) from the spokesperson will be distributed to the PAC. For approved proposals, any specialized or non-commercial equipment brought to FRIB will require an evaluation be prepared with FRIB staff to review potential hazards and planned mitigation strategies. Transportation of all radioactive source materials and activated materials (for example, targets) must comply with the FRIB Laboratory radioactive materials license and must be approved in writing by the FRIB Laboratory Radiation Safety Officer. 

Letters of intent

Letters of Intent will be accepted for the following: 

• Programs that require significant investments in new instruments, and requests for new beams or beam properties. 
• Specifically for PAC4, Letters of Intent are also invited for potential experiments with the High Transmission Beam Line (HTBL) in the High rigidity Rare Isotope Beams at Zero Degrees (HiRIBZ) mode. The High Transmission Beam Line (HTBL) and the Spectrometer Section (SPS) constitute the two components of the High Rigidity Spectrometer. Prior to the completion of the SPS, the HTBL will be available for experiments in the High rigidity Rare Isotope Beams at Zero Degrees (HiRIBZ) mode. In the HiRIBZ mode, beams can be delivered to a target station located at the mid-point of the HTBL with the second half of the HTBL operated as a spectrometer for the reaction residues.  Alternatively, beams can be delivered to the end of the HTBL and detector systems can be employed as end stations in experiments with fast rare-isotope beams (see details on the HTBL on the FRIB instruments website).  

Letters of Intent can now be submitted on the FRIB Scientific User Portal. The submitter of the Letter of Intent will receive feedback from the PAC on how a proposal for the science described might be received in the future and may receive guidance on what would be expected in a full proposal.

Privacy

Proposals will be kept confidential as allowed by State of Michigan law, but will be available to PAC members, FRIB operations, and technical staff as needed.

Contact

Please contact the Manager for User Relations Jill Berryman with any questions you may have.