LHC @ Home is a voluntary computing project on the BOINC platform , organized by CERN employees ( fr. Conseil Européen pour la Recherche Nucléaire ) to carry out the calculations necessary for the construction and operation of the Large Hadron Collider . In the course of these calculations carried out by volunteers on their home computers, the behavior of a beam of charged particles is simulated with various parameters of the action of the accelerator control magnets [1] using the SixTrack program. In the course of the calculations, the possibility of adding Garfield and ATLAS design modules to simulate collisions of proton beams in detectors was considered in the project, but they were never implemented (at least on the BOINC platform) [2] . The possibility of using the LHC @ home project for processing the experimental data was also considered, but the main difficulties are associated with the large amount of information required for transmission to remote computers (hundreds of gigabytes ) [3] . For this task, the grid system LCG is more convenient.
| LHC @ home | |
|---|---|
| Platform | BOINC |
| Downloadable software | 2 MB ( SixTrack ) |
| The amount of job data downloaded | 200–400 KB ( SixTrack ) |
| The amount of job data sent | 35KB ( SixTrack ) |
| Disk space | 14 MB |
| Used memory | 70 MB |
| Graphical interface | no (in development) |
| Average job calculation time | 1–23 hours |
| Deadline | 7 days |
| Ability to use GPU | not |
The project is managed by the Distributed Computing Manager ( BOINC Manager ), performing calculations in the background and periodically requiring an Internet connection to receive new tasks and send calculation results.
The calculations in the framework of the project started on the BOINC platform in September 2004 [4] . Initially, the number of participants in the project was limited to 1,000 people, then this value was repeatedly increased and as a result was finally canceled. As of June 5, 2010, more than 99,000 users (254,000 computers ) from 182 countries participated in the project. In the period from February 2009 to September 2011, tasks were issued extremely rarely; from September 19, 2011, assignments were resumed [4] . In March 2011, the LHC @ Home 2.0 (Test4Theory) project was launched, the purpose of which is to simulate collisions of proton beams.
Content
SixTrack
| External images | |
|---|---|
| Parameter space maps within which the beam is stable | |
| [one] | |
| [2] | |
The program simulates the movement of 60 particles moving along the accelerator ring for 1,000,000 cycles, which corresponds to less than 10 seconds of real time the beams are in the accelerator [5] . By repeating the launch of the program several times, one can choose the configuration of the parameters of the magnets, in which the beam remains stable during its motion along the accelerator ring (it has a stable periodic, rather than a chaotic orbit). The data obtained during the simulation are used to exclude situations in which a particle beam may become unstable during real experiments (which, at best, can lead to a rapid local temperature rise, as a result of which magnets can change from a superconducting state to a normal state and stopping the accelerator for several hours, and at worst - to the failure of some detectors) [6] . During the simulation, one can also take into account the effects of electromagnetic interaction of bunches in the composition of the beams during their movement ( English Collective instabilities ) and collisions in detectors ( English Beam-beam effect ), without which it is impossible to increase the number of bunches in the beam, the number of charged particles in the bunch and , respectively, the luminosity of the collider as a whole.
Development History [7]
The SixTrack program was developed by Frank Schmidt [ when? ] ( eng. Frank Schmidt ) on the basis of a program previously developed for modeling the beams of the electron-positron collider DESY [8] . In 2003, Eric McIntosh ( Eng. Eric McIntosh ) and Andreas Wagner ( Eng. Andreas Wagner ) from the IT department of CERN started testing the Compact Physics Screen Saver (CPSS) screensaver , which ran the SixTrack program in the background on the computers of CERN employees with debugging target. In January 2004, Ben Sigal ( Eng. Ben Segal ) and François Gray ( Eng. Francois Gray ) expressed the idea of popularizing the idea of distributed computing in order to familiarize the general public with the computational tasks facing CERN. A little later, in collaboration with Dave Andersen ( English Dave Anderson ), Director of the SETI Institute , by the efforts of students Christian Shettrup ( Eng. Christian Søttrup ) and Jacob Pedersen ( Eng. Jakob Pedersen ), who worked at that time on writing master's theses , under the leadership of Ben Segal, an adaptation of the calculation module for the emerging BOINC platform [9] was started (a little later Karl Chen, a student, joined the development team). A student, Yasenko Zhivanov ( born Jasenko Zivanov ) developed a graphic part. Finnish students Kalle Happonen ( Eng. Kalle Happonen ) and Mark Degerholm ( Eng. Markku Degerholm ) set up the server part of the project, which by September 2004 made alpha and beta testing on 25 machines first at CERN and then with experienced BOINC users, which ultimately resulted in an increase in the number of active project participants to 6000.
| External images | |
|---|---|
| SixTrack Development Team | |
| From left to right: Frank Schmidt, Jukka Klem ( Eng. Jukka Klem , Andreas Wagner, Erik Mackintosh, Ban Segal) | |
In November 2006, project management was transferred outside CERN to the University of London , and in August 2011 the project returned to CERN again.
LHC @ Home 2.0 (Test4Theory)
Currently, there is also a project LHC @ home 2.0 , which is open to everyone [10] . The goal of this project is to simulate collisions of proton beams with the aim of comparing the experimental and model data and identifying deviations. Within the framework of the project, simulations of potential manifestations of “ New Physics ” outside the Standard Model are being carried out [11] .
For the project to work, in addition to the BOINC Manager program, a VirtualBox virtual machine is required in which the Scientific Linux operating system is launched and the corresponding calculations are performed.
ATLAS @ Home
Also in June 2014, the ATLAS @ Home project was launched, the goal of which is to simulate particle collisions in the framework of the ATLAS detector of the same name in addition to the LCG grid.
Interesting Facts
- During the development of computational code running on various hardware platforms, programmers were faced with a situation of different errors in calculating the functions of the exponent and the logarithm , and, as a result, errors in the validation of tasks. Thus, the computational code of the project can be a kind of test for compliance with the IEEE 754 standard for various hardware platforms and compilers [5] .
See also
- The Large Hadron Collider
- Voluntary calculations
- BOINC
Notes
- ↑ Elements: Magnetic System LHC
- ↑ LHC @ home Archived October 2, 2010.
- ↑ LHC @ home
- ↑ 1 2 BOINCstats | LHC @ Home - Credit overview Archived July 19, 2006.
- ↑ 1 2 Numerical simulations
- ↑ Phys. Rev. ST Accel. Beams 13, 061002 (2010): Beam-related machine protection for the CERN Large Hadron Collider experiments
- ↑ SixTrack history in LHC @ home
- ↑ LHC @ home Archived October 2, 2010.
- ↑ FatBat Homepage
- ↑ Elements: The LHC @ home 2.0 project opens for everyone Archived on September 12, 2011.
- ↑ High Energy Physics simulations | LHC @ home 2.0
Links
- List of projects on the BOINC platform
- All Russian teams (inaccessible link)
- All Russian participants (inaccessible link)
- Main site of the project
- Description of the project on boinc.ru
- Translation of official project pages
- Translation of frequently asked questions about the project
- Information on the progress of construction of the LHC accelerator
- McIntosh E., Schmidt F., de Dinechin. F. Massive Tracking On Heterogeneous Platforms // 9th International Computational Accelerator Physics Conference (ICAP), October 2006
- Herr Werner; Kaltchev DI; McIntosh E .; Schmidt F. Large-scale beam-beam simulations for the CERN LHC using distributed computing systems // 10th European Particle Accelerator Conference, Edinburgh, UK, 26–30 Jun 2006, pp.526
Discussion of the project in the forums: