The China Jinping Underground Laboratory (CJPL) represents the world’s deepest underground laboratory with the lowest cosmic-ray muon flux, largest usable space, extremely low radiation background, and top-notch comprehensive conditions. With ongoing support from the National Natural Science Foundation of China (NSFC), various deep-earth scientific research projects have been systematically conducted at CJPL, achieving significant results such as direct detection of dark matter and nuclear astrophysics. To further leverage CJPL’s unique advantages and promote international collaborative research in deep underground science, NSFC has established the "Jinping Large Scientific Infrastructure International Cooperation Research Program." Following the organizational model of NSFC Major Research Plan program, this program supports integration projects, key projects, and cultivation projects to support collaboration between Chinese scientists and leading international researchers. The program specifically targets research directions such as "Neutrinoless Double Beta Decay Search," "Deep Underground Nuclear Astrophysics," and "Deep Underground Frontier Science Exploration," aiming to position CJPL as a globally leading, internationally accessible hub for deep-underground scientific research.

I. Scientific Objectives

Leveraging the unique strengths of CJPL, this international cooperation program addresses three major scientific goals: searching for neutrinoless double beta decay, precise measurement of key nuclear astrophysical reactions, and exploring frontier deep underground science. The program aims to improve experimental sensitivity, acquire accurate data, and foster new principles, methods, and technologies crucial for breakthroughs in future underground science experiments.

II. Core Scientific Issues

1. Neutrinoless double beta decay search.

2. Direct measurement of key nuclear astrophysical reactions within the Gamow window.

3. Exploration of new principles, methods, and technologies in frontier deep underground science.

III. Application Requirements

1. The applicant shall form a joint research team with foreign researchers and submit a joint application. The foreign collaborators should have a clear division of responsibilities and make substantive contributions to the proposed research, as well as spend a certain period working in China each year for specific experiments or research.

2. Applicants shall contact CJPL in advance (email: cjpl@tsinghua.edu.cn, email title: Pre-approval for Jinping International Cooperation Research Program) and obtain a pre-approval letter from CJPL, stating that the proposed project will be allowed to proceed at CJPL if it passes NSFC review (template provided in Appendix II).

IV. Project Types and Funding Areas for 2025

Project types to be solicited and funded this year include:

1. Integration Project

Neutrinoless double beta decay using enriched scintillation crystals with dual-phase readout, encompassing:

· Research on key technologies for scalable preparation Mo-100 enrichment and low background lithium molybdate crystals. To meet the requirement of ton-scale experiment, conduct research on key technologies in the scalable enrichment of Mo-100 isotopes and the growth of low background lithium molybdate crystals.

· Research on key technologies for readout electronics of the scintillation bolometer detector.  To meet the signal readout and background control requirement, conduct research on key technologies for low background, high-performance readout electronic devices.

· Development of a Testing Platform for low background scintillation bolometer detectors. To meet the detector testing needs for ton-scale experiments, conduct research on key technologies such as low background cryostat, environmental radiation shielding, signal processing and analysis technologies.

· Physical design of a ton-scale experiment and the operation of a Kg-scale prototype. Conduct physical design for a ton-scale experiment, including experimental background models and expected sensitivities. Build and operate a kg-scale experimental prototype in the Jinping Underground Laboratory to validate the key technologies.

Applications for Integration Projects must comprehensively cover all the research tasks listed above. Applications addressing only partial aspects of these tasks will not be accepted.

2. Cultivation Project

Frontier deep underground science exploration, including but not limited to quantum technologies, solar neutrino detection, high-sensitivity detection technologies based on superconducting transition edge sensors (TES) and so on.

V. Funding Plan for 2025

· One integration project is to be funded. NSFC budget is up to 30 million RMB per project (direct costs) for a duration of 5 years, from January 1, 2026 to December 31, 2030.

· Up to three cultivation projects are to be funded. NSFC budget is up to 1.2 million RMB per project (direct costs) for a duration of 4 years, from January 1, 2026 to December 31, 2029.

Ⅵ. Application Guidelines   

1. Eligibility Requirements for Applicants

(1) Applicants must have experience in undertaking basic research projects.

(2) Applicants must hold senior academic ranks (titles).

(3) Postdoctoral researchers, individuals currently pursuing graduate degrees, and individuals without an affiliation or whose affiliation is not registered as a NSFC host institution are ineligible to apply.

2. Requirements for International Collaborators

(1) International collaborators must have experience conducting scientific research abroad as a project leader and managing research projects funded by the host country.

(2) International collaborators must hold senior academic ranks (titles) in the host country.

3. Limits on Parallel Application

(1) An applicant may apply for only one project under this program.

(2) The total number of NSFC projects that researchers with senior academic ranks (or titles) can apply for or undertake (as the PI or major participants) is limited to two projects. All project categories (Cultivation Projects and Integration Projects) shall be counted within the number limits.

(3) More requirements can be found in the NSFC 2025 Guide to Programs.

4. Application Requirements

Applicants and their host institutions shall carefully read and follow the guidelines provided in this call text, the NSFC 2025 Guide to Programs, and the Notice on the Application and Completion of NSFC Projects in 2025.

(1) No hard copy of the application is needed. Applications must be submitted electronically between July 7 and August 22 (by 16:00) in 2025.

· Applicants shall submit a completed online application to the NSFC’s Grants System (http://grants.nsfc.gov.cn). The procedure is to log into the Grants System as the PI, click the “online submission” button, then click the “new application” button, select “Science Fund for Global Challenges and Sustainability（面向全球的科学研究基金项目）”, and then “Large Scientific Infrastructure (CJPL)（重大科学基础设施(CJPL)）”， and choose one project type from "Cultivation Project（培育项目）", or "Integration Project（集成项目）," based on the specific research content of the application. Please choose the appropriate application code based on the proposed research topic.

· The number of collaborating research institutions is limited to a maximum of 4 for the Integration Project and a maximum of 2 for the Cultivation Project.

· Project titles, scientific objectives, research content, technical approach, and budget must be proposed by the applicant, aligned with the core scientific questions and funding priorities of this program.

· Applicants shall complete and submit electronic application forms and attachment materials online according to the instructions and outlines provided in the NSFC’s Grants System. The main part of the application shall be written in English. Applications that do not meet the requirements will not be accepted.

·  International collaboration is required. A Collaborative Agreement between the Chinese applicants and the international partners must be uploaded as an attachment (template provided in Appendix I). Applications that do not meet the requirements will not be accepted.

· The applicant must submit English-language CVs for the Principal Investigator, key domestic participants, and international collaborators as part of the proposal attachments.

· Applicants must submit a scanned copy of the pre-approval letter issued by CJPL as the proposal attachments. Applications that do not submit the document will not be accepted.

(2) The host institutions shall verify each item of the electronic application package via NSFC’s Grants System and submit all proposals and supplementary documents to NSFC by 16:00 on August 22, 2025. Late applications will not be accepted.

(3) To monitor project progress, an annual academic exchange meeting will be held for all funded projects. In addition, academic seminars in relevant research fields may be organized from time to time. Principal Investigators of funded projects are required to participate in academic exchange activities organized by the program's advisory expert group and management team.

5. Contact Information

Division III, Department of International Programs:

WU Congcong, SONG Shengqiang 

Tel: 010-6232 5143，010-6232 6440

Email: wucc@nsfc.gov.cn, songshengqiang@nsfc.gov.cn

NSFC Grants System technical support:  +86-10-6231 7474

Annexes

· Template of the Collaborative Agreement (Appendix I)

· Template of Pre-approval Letter for the Collaborative Research (Appendix II)