HERA

HERA (Hadron Elektron Ring Anlage) was a 6.3-kilometer-cirumference proton-electron collider at DESY, Hamburg, Germany.

The storage ring started in 1992 and joined the effort of 11 countries.

HERA had four huge detectors and associated experiments H1, ZEUS, HERMES and HERA-B.

The experiments were dismantled in 2007

HERA-B detector stopped taking data in 2003.

Detectors
Lab

HERA Status

Bit Preservation

Well-defined data and MC sets mainly in plain ROOT format. Migration to new tape generations planned.

Data

Transferred to DPHEP area on DESY dCache. 2 tape copies (different media generations 1.2 PiB) plus disk cache (700 TiB) for on-going analyses. A copy of the ZEUS data is also available at MPCDF (Munich) and further copies are under consideration.

Documentation

Non-digital documentation catalogued and stored in the DESY library archive; some digitized. Collaboration software notes in INSPIREHEP. Important internal web pages collected to a web-server with static content.

Software

“In the best of all worlds we would keep the software alive i.e. compilable on the latest Linux with the latest library versions”

We now follow a “freezing approach”, i.e. a VM with isolated storage and well defined set of external libs

Use Cases

Continued analyses by members of the HERA collaborations

Audience

Primarily the HERA collaborations, but also other physicists interested in HERA data

Value

Analyses, publications and PhDs continue to be produced

Uniqueness

Unique combination of initial state particles and energy

Status

Transitioning from experiment-specific to institutional solutions

Issues

Webservers: tension between production needs and long-term archiving.

Do not underestimate the effort! Experiment expertise fades away quickly once funding stops.

Data preservation must be prepared whilst effort is available!

Outlook

Continued ability to analyse data until 2020 (when support for SL6 stops); Migration to SL7 could extend this; Tape archive will life on.