EBTA proposals

Extensive Beam Time Access (EBTA) is a dedicated access route for experimental projects that require a long preparation phase and beam time of the order of a full reactor cycle or longer. It is designed for complex, high-impact experiments where an early and formal allocation of beam time is needed to secure funding, recruit staff and develop specific equipment.

EBTA is not intended for projects aiming at operating for several years on a given beam port, instrument or location at the ILL. Such long-term activities are handled through dedicated contracts with the ILL and the partner institutions.

Eligible instruments and scope

The EBTA scheme is currently open to proposals for the following instruments: PF1, PF2 and FIPPS. Projects should:

Require an extended preparation period (up to three years between allocation and experiment), and

Request instrument beam time comparable to a reactor cycle or longer.

It is strongly recommended that proposers fully involve at least one ILL scientist in the project from an early stage.

Call schedule

EBTA calls are organised on a yearly basis for the instruments listed above.
For the 2026 transition, a single EBTA call is foreseen in January for the spring round. From 2027 onwards, the scheme is expected to follow a regular annual rhythm.

HOW TO APPLY

1. Fill in the EBTA proposal form. Completing all requested information is essential for safety and health-physics approval and to avoid delays in the assessment of your proposal.

2. Scientific and Technical description : In addition to the form, each EBTA proposal must include a scientific and technical document (typically 5–10 pages) covering the following points: 

• Scientific motivation: clear rationale and scientific objectives of the project.
• Beam time request and preparation schedule: Justification of the requested amount of beam time; a preparation timeline over the coming years, including critical milestones.
• Technical description: Description of the experimental set-up and methodology; identification of potential technical and safety risks; critical milestones in the construction, commissioning and qualification of the set-up.
• Local resource estimate: List of ILL resources required during the preparation period and during the beam time (e.g. Health Physics, Safety Engineers, technical support labs).
• Team outline: Size and composition of the team responsible for preparation and operation of the experiment during beam time.

3. The form and the scientific description should be submitted to the ILL User Office by the deadline indicated in the current EBTA call.

DOCUMENT AND USEFUL LINKS

Current EBTA Call Text (pdf - 151 Ki) (deadlines, scope, practical details and process diagram).
EBTA Proposal Form (docx - 34 Ki) (including sample and safety information) – Word template. Please fill it in and add your detailed scientific description.
EBTA Experimental Report Template (for yearly and final reports) – to be used once an EBTA project is accepted.
 

Review and allocation process

The EBTA process runs in several stages and is aligned, where possible, with the standard ILL proposal evaluation scheme. A schematic flow diagram of the process is provided in the call document (page 3), showing the relation between EBTA and standard proposals.

The proposal (form + scientific document) is evaluated by the relevant ILL Subcommittee, following the usual peer-review practices.
Instrument Responsibles (IRs) provide comments and help identify technical constraints and safety aspects. 

Based on the Subcommittee’s recommendation, ILL management decides whether to allocate beam time to the project in the EBTA framework.
This allocation can be made up to three years before the envisaged experiment and is formally communicated to the proposers, who can then use this commitment to support funding applications, hiring and equipment development

After allocation, the proposers prepare the experiment, in close contact with the ILL (IRs, Safety, Health Physics, engineering support, etc.). 

Within a three-year period, the proposers must demonstrate that the experiment is fully ready and compliant with the ILL’s safety requirements. Once readiness is confirmed, the experiment is scheduled in coordination with the instrument teams and reactor planning. If readiness cannot be demonstrated within three years, the project is normally cut off. An extension is only possible in exceptional cases, where unforeseen circumstances can be clearly identified and a credible path to readiness is presented (see Monitoring section below).

Monitoring of individual EBTA projects

The EBTA framework includes a specific monitoring procedure for each accepted project.  Monitoring is a tool for the ILL to support decisions on beam-time allocation and scheduling. 

Yearly reports: Proposers must submit a yearly progress report, transmitted via the User Office to the relevant Subcommittee and IR. The reports are used to identify potential issues at an early stage and can also serve to advise the collaboration on improvements.

Discussion and recommendation: The Subcommittee and IR discuss each report and formulate a recommendation on the continuation of the project. In case of diverging views, the relevant Subcommittee members and the IR consult to seek a common recommendation. The recommendation is forwarded to the Science Director.

Three-year readiness limit: There is a strict three-year limit for the project to reach experimental readiness. This limit may only be relaxed in justified cases, when unforeseen circumstances have occurred and a clear, realistic plan towards readiness exists.

In exceptional circumstances, monitoring outcomes may lead to adjustments of the planned EBTA schedule, for example in case of:

• Unexpected delays on the user side,
• Changes in the reactor schedule,
• Modifications to the instrument or infrastructure that affect the EBTA project.

Such adjustments remain exceptional, as they may impact already-made beam time commitments.