The status of a Technical Associate Institute is designed for research laboratories or universities that seek to have a close cooperation with the ATLAS Collaboration on primarily technical work for a dedicated project over an extended (multi-year) but limited period of time. They do not intend to join the ATLAS Collaboration as a full member Institution and do not intend to contribute to the ATLAS physics programme.

The principal reason for a Technical Associate membership is cooperation on one or more challenging technical project(s) relevant for the ATLAS Collaboration. These projects are possible in the areas of detector development, engineering, electronics, firmware, software and computing. They may be linked to detector upgrade programmes. Engagement in R&D activities that could potentially be of interest for ATLAS is possible as well. There should be clear benefit to the group joining, as well as to ATLAS, from the application.

Given that no full membership is anticipated, no financial contribution to enter the collaboration and no M&O costs have to be paid. Technical Associate Institutes are not required to contribute to the OT tasks; however, they are welcome to do so, concerning the maintenance and operation of their deliverables.

Technical Associate Institutes appear under a separate heading on the list of ATLAS Institutions. While members from the Technical Associated Institutes do not sign the physics publications of the ATLAS Collaboration, they sign all project-related technical papers where they are involved together with authors from the ATLAS Collaboration.

• Initial contact should be with the ATLAS Spokesperson or with Project or Activity Leaders of Technical Projects in ATLAS.
• The applicant group should prepare an Expression of Interest detailing the interest of the group in a specific project, its background and the involved personnel (scientist, engineers and students) as well as the timeline of the common project between the ATLAS Collaboration and the applicant group and, linked to this, the duration of the association.
• The applicant group will be associated to one or more ATLAS detector systems and/or activity areas and well-defined deliverables should be defined. Long-term maintenance and OT linked to the deliverable of a Technical Associate Institute is the responsibility of the respective system or activity area. The Project Leaders and/or Activity Coordinators have to find appropriate groups (ATLAS Institutions) to cover this. Therefore, it is desirable that Technical Associate Institutes collaborate closely with existing ATLAS Institutions. It is also possible that the Technical Associate Institutes stay engaged beyond the development and construction phase and take longer-term commitments for operation.
• Technical Associate Institutes might partake in the resources available for technical projects in ATLAS, e.g. for upgrade projects or for software and computing projects, from central ATLAS resources or from resources in the respective countries. In the latter case the agreement of the respective national ATLAS community and the funding agency is required and a supporting letter from the corresponding NCP is expected.
• Before Technical Associate Institute status is granted, an agreement between the Technical Associate Institute and CERN (as the Host Laboratory) has to be prepared. Such an agreement should specify the details and deliverables of the project as well as ownership and definition of responsibilities for maintenance and operations. Where the technical project involves a contribution to an ATLAS Upgrade Project, the Technical Associate Institute has to comply with the agreed ATLAS procedures for preparation and implementation including critical reviews and timelines.
• The agreement with CERN is presented by the Spokesperson to the ATLAS CB, and a formal vote on the admission is taken. After admission by the CB and after signature of the agreement the Technical Associate Institute status is granted. The admission of a new Technical Associate Institute does not require an endorsement by the RRB, as the CB composition is unchanged; however, the RRB would be notified.