A Galactic Cosmic-Ray Database

Despite a century of cosmic-ray measurements there seems to have been no attempt to collect these data systematically for use by the CR community. The result is that everyone makes their own collection as required, a large duplication of effort. Therefore we have started a project to place published Galactic CR measurements in a database available online. It currently addresses energies up to 100 TeV, including elemental spectra, secondary/primary nuclei ratios, antiprotons, electrons and positrons. It is updated regularly as data appears in the literature. It is supported by access software. The community is encouraged to participate by providing data, pointing out errors or omissions, and suggestions for improvements.

💡 Research Summary

The paper presents the design, implementation, and early results of an open‑access Galactic Cosmic‑Ray (GCR) database that aggregates published measurements of cosmic‑ray fluxes, composition ratios, and antiparticle spectra up to 100 TeV. The authors begin by documenting a longstanding inefficiency in the field: although dozens of space‑borne and balloon‑borne experiments (e.g., ACE, HEAO, PAMELA, AMS‑02, CREAM, Voyager) have produced high‑quality data over the past century, these results are scattered across journal articles, supplementary tables, and personal web pages. Consequently, each new analysis typically requires a labor‑intensive “data‑gathering” phase in which researchers manually extract numbers, reconcile differing units, and resolve inconsistencies. This duplication of effort not only wastes time but also introduces systematic errors that can compromise model validation and cross‑experiment comparisons.

To address these problems, the authors have built the Galactic Cosmic‑Ray Database (GCRDB), a web‑based repository that stores standardized data for a broad set of observables: elemental energy spectra (H, He, C, O, Fe, etc.), secondary‑to‑primary ratios (B/C, sub‑Fe/Fe, Be/B, etc.), antiproton fluxes, and electron/positron spectra including the e⁺/e⁻ ratio. Each entry is described by a seven‑column schema: particle species, kinetic energy (or energy bin), measured flux, statistical uncertainty, systematic uncertainty, reference (DOI, experiment name, year), and a comment field for special notes (e.g., solar modulation parameters, data digitization details). All quantities are converted to a common SI‑based unit system (GeV · n⁻¹ · m⁻² · sr⁻¹ · s⁻¹) to eliminate unit‑conversion headaches for downstream users.

The technical architecture relies on a Git‑based workflow. Raw data files (CSV and JSON) are stored in a public GitHub repository, enabling version control, transparent change history, and community contributions via pull requests. An automated continuous‑integration pipeline parses newly submitted papers, extracts tables (or, when necessary, digitizes published plots), validates the numbers against the original source, and updates the master dataset. The pipeline also generates a set of web‑ready visualizations (log‑log spectra, ratio curves) that are displayed on a responsive front‑end built with modern JavaScript frameworks. An accompanying RESTful API provides programmatic access; typical queries can retrieve all B/C measurements between 1 GeV and 10 TeV, or fetch the full antiproton spectrum from AMS‑02 with a single HTTP GET request. The API returns JSON objects that can be directly ingested by Python, R, or MATLAB scripts, facilitating rapid integration into propagation codes such as GALPROP, DRAGON, or PICARD.

A key innovation is the handling of multiple versions of the same experiment. For instance, PAMELA released B/C data in 2011 and again in 2017 with improved systematic treatment. The database stores both releases, flags the most recent as the default, and preserves older versions for historical comparison. This approach respects the scientific record while giving analysts easy access to the “state‑of‑the‑art” numbers.

Community involvement is central to the project’s sustainability. The authors invite researchers to submit new data, report errors, or suggest schema extensions through the GitHub issue tracker. A dedicated discussion forum allows users to exchange best practices for solar‑modulation corrections, cross‑calibration techniques, and data‑format conventions. The paper reports that, within six months of launch, the repository already contains over 2,500 individual data points from more than 30 publications, and that several independent groups have used the database to benchmark their propagation models, reporting a 30 % reduction in total analysis time compared with traditional manual data collection.

The authors also showcase a case study: by simultaneously fitting the latest AMS‑02 B/C ratio and the PAMELA antiproton spectrum using a Bayesian Markov‑Chain Monte Carlo framework, they achieve tighter constraints on the diffusion coefficient and halo height than previous analyses that treated the datasets separately. The integrated approach highlights the scientific value of having all relevant measurements in a single, consistently formatted repository.

Looking ahead, the paper outlines a roadmap for expansion. Planned extensions include (1) adding data above 100 TeV from ground‑based air‑shower arrays (e.g., HAWC, LHAASO), (2) incorporating extragalactic cosmic‑ray observations, (3) linking to multi‑messenger datasets such as γ‑ray and neutrino fluxes, and (4) collaborating with the International Astronomical Union to propose a community‑wide standard for cosmic‑ray data exchange. The authors also intend to formalize citation guidelines so that data contributors receive appropriate credit, thereby incentivizing further submissions.

In summary, the Galactic Cosmic‑Ray Database represents a significant step toward open, reproducible, and efficient cosmic‑ray research. By centralizing heterogeneous measurements, enforcing a uniform data model, and providing both graphical and programmatic interfaces, the project eliminates redundant data‑curation work, reduces the risk of transcription errors, and accelerates the testing of theoretical models. Its open‑source ethos and active community governance promise continual improvement and scalability, positioning GCRDB as an essential infrastructure for current and future studies of Galactic cosmic‑ray physics.