1. Building a UK Computing Grid for Particle Physics
GridPP
Building a UK Computing Grid for Particle Physics

2. 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….

3. How will LHC work?
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.

4. ATLAS CMS LHCb ALICE 4 LHC Experiments
general purpose: origin of mass, supersymmetry, micro-black holes
2,000 scientists from 34 countries
CMS
general purpose detector
muon tracking, electromagnetic calorimeter, central tracking and hadron calorimeter
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

5. The LHC Data Challenge A particle collision = an event
Physicist's goal is to count, trace and characterise 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

6. The LHC Data Challenge Starting from this event…
Selectivity: 1 in 1013
Like looking for 1 person in a thousand world populations
Or for a needle in 20 million haystacks!
..we are looking for this “signature”

7. LHC data 40 million collisions per second
Concorde
(15 Km)
Balloon
(30 Km)
DVD stack with
1 year LHC data
(~ 20 Km)
Mt. Blanc
(4.8 Km)
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
1 Gigabyte (1GB)
= 1000MB
A CD album
1 Terabyte (1TB)
= 1000GB
World annual
book production
1 Petabyte (1PB)
= 1000TB
Annual production of one LHC experiment
1 Exabyte (1EB)
= 1000 PB
World annual information production

8. data 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…

9. LHC Computing Grid (LCG)
By 2007:
100,000 CPUs
- >200 institutions worldwide
building on middleware being developed in advanced grid technology projects, both in Europe and in the USA
Currently running on around 200 sites.

10. LCG monitoring applet Monitor:
resource brokers
virtual organisations
ATLAS
CMS
LHCb
DTeam
Other
SQL queries to logging and book-keeping database

11. GridPP Middleware Development
Grid Data Management
Network Monitoring
Workload Management
Information Services
Security
Storage Interfaces

12. 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 gLite middleware
R-GMA structure

13. 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 EU
>400 software engineers + service support
70 European partners

14. The Grid What the User sees 1 11 Job Submit Event 2 Input Dataset
gridui
JDL
Output Dataset 11
Job Submit Event 2
The Grid

15. What the Grid does Replica Catalog Resource Broker Information Service
Input Dataset 1
gridui
JDL 3
Output Dataset 11
Job Submit Event 2 7 5
Resource Broker
Information Service 6 4
Job Submission Service 9 8
Computing Nodes
Storage
Job Status 10
Logging & Bookkeeping

16. Interoperability LCG collaborates with
to form the worldwide LHC Computing Grid
NorduGrid
OSG

17. 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, from

18. UK Tier-1/A Centre – Rutherford Appleton Laboratory
High quality data services
National and International Role
UK focus for International Grid development
1000 Dual CPU
200 TB Disk
220 TB Tape (Capacity 1PB)
Grid Operations Centre

19. UK Tier-2 Centres ScotGrid SouthGrid LondonGrid
Durham Edinburgh Glasgow NorthGrid
Daresbury Lancaster Liverpool
Manchester Sheffield
SouthGrid
Birmingham Bristol Cambridge
Oxford RAL PPD Warwick
LondonGrid
Brunel Imperial QMUL RHUL UCL

20. Applications – US experiments
BaBar (SLAC)
investigating asymmetry between matter and antimatter
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 (data handling system) with JIM (Job Information and Management)

21. 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
up to 40 million events per month on Grid since August 2004
QCDGrid
For Quantum Chromodynamics (QCD)
Currently a 6-site data grid
Key technologies used
- Globus Toolkit 2.4
- gLite
eXist XML database
ILDG Browser Client 1.5
Multi-terabyte storage facility

22. Applications - LHC ATLAS LHCb CMS
GANGA software framework (jointly with LHCb)
data challenges
producing Monte Carlo data
10 million CPU hours
per year
LHCb
DIRAC software to submit analysis jobs using Grid
2006 analysis job completion efficiency improved to 91%
CMS
Monte Carlo production, data transfer, job submission
CMS transfers top a petabyte a month for the last three months