Physical Sciences - Particle Physics at CERN and elsewhere

Transcription

1 Disciplinary Case Study 1 Physical Sciences - Particle Physics at CERN and elsewhere Jürgen Knobloch CERN/IT ERPANET/CODATA International Archiving Workshop on the Selection, Appraisal, and Retention of Digital Scientific Data Biblioteca Nacional, Lisbon, Portugal December 2003 last update: 07/01/ :49 Jürgen Knobloch - cern-it 1

2 Overview Physics data retention past and future Particle physics laboratory CERN Particle physics data flow data types data volume Keeping digital data available In the longer term For the public use Some examples LEP data long-term availability QUAERO opening data to the public Particle Data Group Limits of re-using data Conclusion Points for discussion Jürgen Knobloch- cern-it Slide-2

3 Physics data Laboratory, Karnak, Egypt > 3000 years Jürgen Knobloch- cern-it Slide-3

4 are not always cast in stone Law of motion Galileo s notebook ~ 1638 Jürgen Knobloch- cern-it Slide-4

5 Enrico Fermi Notebook recording the first controlled, self-sustaining nuclear chair reaction, December 2, 1942; Records of the Atomic Energy Commission; Record Group 326; National Archives. Jürgen Knobloch- cern-it Slide-5

6 or on film Bubble chamber CERN, 1973 Jürgen Knobloch- cern-it Slide-6

7 now it is all electronic! CERN UA Jürgen Knobloch- cern-it Slide-7

8 CERN CERN: Annual budget: ~1000 MSFr (~700 M ) Staff members: 2650 Member states: Fellows, Associates CERN users CERN (founded 1954) = Conseil Européen pour la Recherche Nucléaire European Organisation for Nuclear Reseach Particle Physics last update 07/01/ :49 km circumference Jürgen Knobloch- cern-it tunnel Slide-8

9 CERN where the Web was born Tim Berners-Lee Fist Web Server WSIS, Geneva, October 10-12, 2003 Jürgen Knobloch- cern-it Slide-9

10 CERN s 20 member states CERN Convention: shall provide research of pure scientific and fundamental character shall have no concern with work for military requirements and the results of its experimental and theoretical work shall be published or otherwise made generally available. Jürgen Knobloch- cern-it Slide-10

11 and scientists from the rest of the world: OBSERVERS: UNESCO EU Israel Turkey SPECIAL OBSERVERS (for LHC): USA Japan Russia Jürgen Knobloch- cern-it Slide-11

12 Other accelerators around the world Jürgen Knobloch- cern-it Slide-12

13 Particle Physics Establish a periodic system of the fundamental building blocks and understand forces Jürgen Knobloch- cern-it Slide-13

14 Methods of Particle Physics The most powerful microscope last update Creating 07/01/ :49 conditions Jürgen Knobloch- cern-it similar Slide-14 to the Big Bang

15 Particle physics data From raw data to physics results e + e - Z 0 f _ f Raw data Convert to physics quantities Detector response apply calibration, alignment Interaction with detector material Pattern, recognition, Particle identification Fragmentation, Decay, Physics analysis Basic physics Results Reconstruction Analysis Simulation (Monte-Carlo)

16 HEP Data Analysis Detector description Generate Generate Events Events Build Build Simulation Simulation Geometry Geometry Detector alignment Detector calibration Reconstruction parameters Physics Build Build Reconstuction Reconstruction Reconstruction geometry Geometry Geometry Reconstruct Reconstruct Events Events Analyze Analyze Events Events Simulation geometry Simulate Simulate Events Events Raw Data Jürgen Knobloch- cern-it ESD AOD Slide-16

17 CERN data archiving policy "CERN is not just another laboratory. It is an institution that has been entrusted with a noble mission which it must fulfil not just for tomorrow but for the eternal history of human thought. (Albert Picot, 3rd Session of CERN Council, Geneva, 1955) "Rules applicable to archival material and archiving at CERN CERN Operational circular No. 3 (1997) Historical and scientific archives Implemented by the CERN archivist Anita Hollier Does not specifically cover digital physics data Jürgen Knobloch- cern-it Slide-17

18 Technical issues shelf life technology cycle - metadata Jürgen Knobloch- cern-it Slide-18

19 Data archiving - LEP Large Electron-Positron collider (LEP) was running from ( GeV) Accelerator and experiments dismantled to make room for LHC Four experiments ALEPH, DELPHI, L3, OPAL Officially terminating in the near future Experiments request to keep the analysis of data alive (as long as possible/reasonable) In case that other experiments (e.g. at LHC) see new phenomena that are within the reach of LEP Require also to be able to re-run simulation (Monte Carlo). Jürgen Knobloch- cern-it Slide-19

20 LEP data agreement Keep the (FORTRAN) software running as is. No further development or maintenance to central software such as CERNLIB Have the required data available in the standard CERN hierarchical mass storage system CASTOR. Carry the data forward in case of MSS evolution. Have the software and data access running on a special cluster of LINUX computers. Carry software with the operating system and compiler forward as much as possible without major effort Run the whole as a Museum system Jürgen Knobloch- cern-it Slide-20

21 Issues and concerns Event displays of some experiments depend on external commercial software. Security updates for a given OS version are available for a limited time only. The system requires hopefully limited manpower for central support. The experiments need to keep it alive and perform regular tests. Major changes in hardware technology cannot be accommodated (what about emulators?). The data cannot be analyzed in a meaningful way by people who were not involved in the original collaboration. Jürgen Knobloch- cern-it Slide-21

22 QUAERO Making HEP data publicly available Developed by Bruce Knuteson Jürgen Knobloch- cern-it Slide-22

23 Data Monte Carlo Signal - Background Jürgen Knobloch- cern-it Slide-23

24 Quaero - choices Jürgen Knobloch- cern-it Slide-24

25 Quaero policy Jürgen Knobloch- cern-it Slide-25

26 HEP-wide data compilation: Particle Data Group (PDG) Jürgen Knobloch- cern-it Slide-26

27 PDG: Rosenfeld tables First review of particle properties & data: Hyperons and Heavy Mesons (Systematics and Decay) by M. Gell-Mann and A. H. Rosenfeld, Ann.Rev.Nucl.Sci. 7 (1957) 407 Separate efforts at LBL and CERN joined in 1964 Rev.Mod.Phys. 36 (1964) 977 Particle Data Group: Maintaining a data-base of experimental results. More than 20,000 measurements from 6000 papers. Review and the Booklet are published in even-numbered years. Web version updated between printed editions Jürgen Knobloch- cern-it Slide-27

28 PDG: Particle properties Jürgen Knobloch- cern-it Slide-28

29 PDG: Compilations Cross-sections Structure functions Jürgen Knobloch- cern-it Slide-29

30 PDG: Following history can be revealing! Jürgen Knobloch- cern-it Slide-30

31 The next step: LHC (Large Hadron Collider) Jürgen Knobloch- cern-it Slide M cost 27 km circumference 100 m underground

32 Challenge 1: Large, distributed community ATLAS Offline software effort: 1000 person-years per experiment CMS Software life span: 20 years ~ 5000 Physicists around the world -around the clock LHCb Jürgen Knobloch- cern-it Slide-32

33 Challenge 2: Data Volume Annual data storage: PetaBytes/year Balloon (30 Km) CD stack with 1 year LHC data! (~ 20 Km) Concorde (15 Km) 50 CD-ROM = 35 GB 6 cm Mt. Blanc (4.8 Km) Jürgen Knobloch- cern-it Slide-33

34 Challenge 3a: Find the Needle in a Haystack Jürgen Knobloch- cern-it Slide-34

35 Challenge 3a: Find the Needle in a Haystack 9 orders of magnitude! All interactions The HIGGS Rare phenomena Huge background Complex events Jürgen Knobloch- cern-it Slide-35

36 Challenge 3b: Provide mountains of CPU Calibration Reconstruction Simulation Analysis For LHC computing, some 100 Million SPECint2000 are needed! 1 SPECint2000 = 0.1 SPECint95 = 1 CERN-unit = 4 MIPS - a 3 GHz Pentium 4 has ~ 1000 SPECint2000 Jürgen Knobloch- cern-it Slide-36

37 We count on the Grid - what about archiving? Jürgen Knobloch- cern-it Slide-37

38 Limits of re-using data Example: Fischbach et al. re-analysing after 100 years data from Eötvös classic experiment concerning the proportionality of inertial and gravitating masses. Eötvös had an accuracy of 1/ Fischbach et al. used the data to claim the discovery of the fifth force! Influence of the architecture of the building, the geology and people moving about make the conclusion rather difficult to say the least! Jürgen Knobloch- cern-it Slide-38

39 Points for discussion Experimental physics is publicly funded and expensive LHC costs Not easy to repeat Experimental data are useless without documentation, metadata, and software Technology evolution is a serious burden Have to keep data alive (re-copying) What is the right level of archiving? A la Particle Data Group reliable, long-term Four vectors limited possibilities not always useful (Mini)-DST requires more expertise Making raw and intermediate data publicly available Education a clear case that is pursued by several groups Scientists are rather hesitant to do it in general Jürgen Knobloch- cern-it Slide-39