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The Xenon VO (xenon.biggrid.nl) is the incubator grid community for work on the international Xenon 1T and related experiments in the search for dark matter. Members of the VO will work to build, understand and analyse the detector and resutls related to the Xenon experiment and to "Monte-Carlo" studies that will be used to design, build and understand the detector, as well as work with the supporting computing infrastructure to make this happen.


Science case

In the Universe, only 4% of what we can see exists of matter that we know, built up of atoms. No less than 96% of the Universe however, exists of what we now call dark energy (72%) and dark matter (23%).

Dark matter doesn't produce or reflect light en thus we cannot see it. However, we are sure it exists, judging from amongst other things the movement of stars and solar systems and other astronomical observations. Next to that, we expect to find dark matter all around us, here on Earth. The most likely candidate for dark matter is the WIMP (Weakly Interacting Massive Particle), a heavy particle participating in weak force. Because of this weak force, the WIMP has almost no interaction with other particles, meaning it hardly collides with other particles.

Technical case

Nikhef, in collaboration with BiG Grid, is currently running a pilot project to incubate the VO for the evaluation of infrastructure suitability for the Xenon 1T collaboration, aimed at detector construction and experiment analysis for the search of dark matter using Xenon detectors. Codes for simulation that run on a single system have already been developed and bench marked (600k events can be generated in 1 PNU), but many hundreds of millions of events will be needed, in many configurations.

Contact and technical details

lcg-infosites --vo xenon.biggrid.nl wms
lcg-infosites --vo xenon.biggrid.nl lfc
lcg-infosites --vo xenon.biggrid.nl ce
#CPU    ComputingElement
2324    juk.nikhef.nl:8443/cream-pbs-short
2324    juk.nikhef.nl:8443/cream-pbs-medium
2324    gazon.nikhef.nl:2119/jobmanager-pbs-short
2324    gazon.nikhef.nl:2119/jobmanager-pbs-medium
2324    trekker.nikhef.nl:2119/jobmanager-pbs-short
2324    trekker.nikhef.nl:2119/jobmanager-pbs-medium
lcg-infosites --vo xenon.biggrid.nl se
Avail Space(Kb) Used Space(Kb)  Type    SEs
17591626039     0               n.a     tbn18.nikhef.nl

Current work

At this moment, the Xenon collaboration does not use Grid computing, either at the national or international level. Nikhef wants to promote this in the collaboration, with the support of BiG Grid, by taking the role of ‘incubator’ for this effort within the collaboration, establishing the base infrastructure for running the collaboration on the e-Infrastructure including VO support, basic brokering and cataloging services, and demonstrating the effective use of the infrastructure for the collaboration, based on scaling-out the existing Monte-Carlo codes.

The pilot phase proposed here will:

  • demonstrate viability to run the Xenon monte-carlo codes on a distributed HTC infrastructure
  • establish the base community infrastructure (VOMS server, LFC, supporting services) for the global Xenon collaboration
  • act as a nucleus for other collaboration members to add their national resources to the effort

As the collaboration is currently being established, it is important that this demonstrator will show quick results, preferably a simple end-to-end working prototype before the end of August 2011.

When successful, a larger resource request (initially estimated to be 1M PNU per year and 100 TByte) to BiG Grid will follow (to be complemented by similar resource requests in other countries as well).

International case

The Xenon 1T VO (incubating) is being established by BiG Grid, but with the explicit intent to scale out to the collaboration. This by nature will involve sites and services being hosted in multiple countries in Europe and elsewhere. The European Grid Infrastructure EGI and/or Open Science Grid (OSG) resources in the US are likely to be involved in an early stage.

Information that these sites need to allow this VO access to their resources (i.e. to contribute computing and storage power to the Xenon VO) is collected in the ‘VO Identity Cards’, provided by the European Grid Infrastructure EGI to allow collaboration between infrastructures and communities.

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