GridPPBuilding a UK Computing Grid for Particle Physics

www.gridpp.ac.uk

A PPARC funded project

CERN Large Hadron Collider

•The world’s highest energy particle physics accelerator

•Due to turn on in 2007

•Looking for the Higgs boson, supersymmetry, quark-gluon plasmas, micro-black holes….

• LHC will collide beams of protons at an energy of 14 TeV

• Using the latest super-conducting technologies, it will operate at about – 2700C, just above absolute zero of temperature.

• With its 27 km circumference, the accelerator will be the largest superconducting installation in the world.

How will LHC work?

4 LHC Experiments

CMS- general purpose detector

- muon tracking, electromagnetic calorimeter, central tracking and hadron calorimeter

ATLAS- general purpose: origin of mass, supersymmetry, micro-black holes

- 2,000 scientists from 34 countries

LHCb- to study the differences between matter and antimatter

- producing over 100 million b and b-bar mesons each year

ALICE- heavy ion collisions, to create quark-gluon plasmas

- 50,000 particles in each collision

• A particle collision = an event

• Physicist's goal is to count, trace and characterize all the particles produced and fully reconstruct the process.

• Among all tracks, the presence of “special shapes” is the sign for the occurrence of interesting interactions.

One way to find the Higgs boson: look for characteristic decay pattern producing 4 muons

The LHC Data Challenge

Starting from this event…

..we are looking for this “signature”

Selectivity: 1 in 1013

Like looking for 1 person in a thousand world populations

Or for a needle in 20 million haystacks!

The LHC Data Challenge

LHC data

• 40 million collisions per second

•After filtering, 100 collisions of interest per second

• A Megabyte of data digitised for each collision = recording rate of 0.1 Gigabytes/sec

• 1010 collisions recorded each year = 10 Petabytes/year of data

Concorde(15 Km)

Balloon(30 Km)

DVD stack with1 year LHC data(~ 20 Km)

Mt. Blanc(4.8 Km)

1 Gigabyte (1GB) = 1000MBA CD album

1 Terabyte (1TB)= 1000GBWorld annual book production

1 Petabyte (1PB)= 1000TBAnnual production of one LHC experiment

1 Exabyte (1EB)= 1000 PBWorld annual information production

LHC processing

• Simulation: start from theory and detector characteristics and compute what detector should have seen

• Reconstruction: transform signals from the detector to physical properties (energies, charge of particles, ..)

• Analysis: Find collisions with similar features, use of complex algorithms to extract physics…

LHC Computing Grid (LCG)

By 2007:- 100,000 CPU- 300 institutions worldwide

- building on software being developed in advanced grid technology projects, both in Europe and in the USA

Currently running on around 200 sites.

LCG monitoring applet

• Monitor:– resource brokers– virtual

organisations• ATLAS• CMS• LHCb• DTeam• Other

• SQL queries to logging and book-keeping database

R-GMA

• Information and monitoring tool developed by Rutherford Appleton Laboratory

• Matches up users’ jobs with suitable resources

• Monitors the progress of jobs • Deployed in LCG middleware and gLite

R-GMA structure

Enabling Grids for E-sciencE

Deliver a 24/7 Grid service to European science

•build a consistent, robust and secure Grid network that will attract additional computing resources. •continuously improve and maintain the middleware in order to deliver a reliable service to users. •attract new users from industry as well as science and ensure they receive the high standard of training and support they need.

•100 million euros/4years, funded by EC

• >400 software engineers + service support

• 70 European partners

Interoperability

OSG

GridPP – the UK’s contribution to LCG

•19 UK Universities, CCLRC (RAL & Daresbury) and CERN

•Funded by the UK Particle Physics and Astronomy Research Council (PPARC)

•£33m, over 2001-2007

Applications - LHC

ATLAS• GANGA software framework (jointly with LHCb)• data challenges• producing Monte Carlo data

LHCb• DIRAC software to submit jobs using Grid• 2004 data challenge 190m events, 65TB

CMS• Monte Carlo production, data transfer, job submission• Data challenge 75 million events, 150TB

Applications – US experiments

BaBar (SLAC)- investigating asymmetry between matter and antimatter - aim to use LCG to run:

- Monte Carlo events- analysis of real data

SAM and SamGrid (Fermilab)- used by the D0 and CDF experiments and being tested by MINOS- combines SAM (datahandling system) with JIM (Job information and management)

Applications – other experiments

ZEUS• a large particle detector at the electron-proton collider HERA at the DESY laboratory in Hamburg• needs the Grid to respond to increasing demand for MC production• 1 million events on Grid since August 2004

QCDGrid• For Quantum Chromodynamics (QCD) • Currently a 6-site data grid • Key technologies used

- Globus Toolkit 2.4- European Data Grid-eXist XML database

•Multi-terabyte storage facility

Middleware Development

Network Monitoring Security

Information Services

UK Tier-1/A Centre – Rutherford Appleton

Laboratory

• High quality data services• National and International

Role• UK focus for International Grid

development

Grid Operations Centre

•1000 Dual CPU

•200 TB Disk•220 TB Tape (Capacity 1PB)

UK Tier-2 Centres

ScotGridDurham Edinburgh Glasgow NorthGridDaresbury Lancaster LiverpoolManchester Sheffield

SouthGridBirmingham Bristol CambridgeOxford RAL PPD Warwick

LondonGridBrunel Imperial QMUL RHUL UCL