El Gran Colisionador aumenta energía y sigue batiendo récords

El Gran Colisionador de Hadrones (LHC) del Centro Europeo de Investigaciones Nucleares (CERN) consiguió ayer un nuevo récord de energía, al superar el nivel que alcanzó hace tres semanas y lograr que dos haces de protones circularan a 3.5 TeV (teraelectrovolts).

“Esta es la energía más alta lograda en un acelerador de partículas y un paso importante en el camino para iniciar el programa de investigación del acelerador”, indicó el CERN en un comunicado.

Ambos haces se desplazaron en ambas direcciones del túnel de 27 kilómetros del LHC, ubicado bajo la frontera entre Suiza y Francia, en Ginebra.

El objetivo es lograr una aceleración y colisión de protones con una energía de siete TeV, es decir, 3.5 TeV por haz, tarea cuya fecha, de acuerdo con el CERN, será anunciada en breve.

El Gran Colisionador deberá alcanzar esta aceleración próximamente, potencia sin precedentes que permitirá a los científicos del CERN recolectar información inédita sobre el universo y sus fuerzas, que todavía son en gran parte un misterio para el conocimiento humano.

En una primera fase el LHC trabajará a la mitad de su potencial. La energía de aceleración del LHC no deberá superar los siete TeV hasta otoño (boreal) de 2011. Luego, el LHC deberá volver a configurarse para alcanzar el objetivo ulterior de 14 TeV.
El director de Aceleradores y Tecnología del CERN, Steve Myers, dijo que el récord de ayer es “un testimonio de la solidez del diseño del LHC”, así como de “las mejoras que se le han hecho desde su avería en septiembre de 2008”.

En ese entonces, el LHC sufrió desperfectos en algunas de sus conexiones, a muy pocos días de empezar a funcionar por primera vez, lo que obligó a mantenerlo apagado durante 14 meses y supuso un desembolso por reparaciones de más de 20 millones de euros para el CERN.

BREVE RECUENTO. El reinicio de las pruebas del LHC comenzaron el 20 de noviembre de 2009 con 0.45 TeV, pero el acelerador de partículas sufrió varios fallos y debió interrumpirse la prueba. Un TeV equivale a un billón de electronvoltios.

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Los científicos del CERN aceleran los haces para lograr nuevos elementos de análisis para investigar la creación del universo.

Incluso trabajando a la mitad de su potencial permitirá nuevos conocimientos. Los físicos en este ámbito se enfrentan a nuevos desafíos, pues con la aceleración de partículas se simularán condiciones similares a las previas al Big Bang. Con esta prueba se podrán explicar quizás partículas que hasta aquí sólo pudieron ser probadas en teoría. Con una energía de aceleración de 1.8 TeV el LHC superó en noviembre el record que tenía el acelerador estadunidense Tevatron en el Laboratorio Nacional Fermi (Fermilab) en Chicago de 0.98 Tev.

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El CERN anunció que el 19 de marzo, poco después de las 5:20, Hora de Europa Central, dos haces de protones de 3.5 TeV cada uno, circularon exitosamente en el Gran Colisionador de Hadrones (LHC), por primera vez. Esta es la energía más alta jamás alcanzada en un acelerador de partículas, y un importante paso en el camino hacia el inicio del programa de investigación del LHC. El primer intento de colisionar haces de 7 TeV (a razón de 3,5 TeV por haz) se hará en una fecha que será anunciada en el futuro próximo.

El haber obtenido haces a 3,5 TeV es testimonio de la solidez del diseño general del LHC, y de las mejoras que hemos hecho desde la ruptura producida en septiembre de 2008″, explicó Steve Myers, Director para Aceleradores y Tecnología de CERN1. “Y es un gran crédito a la paciencia y la dedicación del equipo del LHC.”

El actual funcionamiento del LHC comenzó el 20 de noviembre de 2009, con el haz circulando primero a 0,45 TeV. Los hitos se sucedieron rápido, con la circulación de haces dobles establecida el 23 de noviembre y un récord mundial de la energía del haz, de 1,18 TeV, establecido el 30 de noviembre. En el momento en que el LHC se apaga en el año 2009, el 16 de diciembre, se había establecido otro récord con las colisiones registradas a 2,36 TeV y las significativas cantidades de datos registrados. Durante parte de la ejecución en 2009, cada uno de los cuatro más importantes experimentos del LHC, ALICE, ATLAS, CMS y LHCb, registraron más de un millón de colisiones de partículas, que fueron distribuidas sin problemas para el análisis de todo el mundo en la rejilla de computación del LHC. Los primeros documentos sobre la física de estos resultados fueron pronto conocidos.

Después de las colisiones de 2,36 TeV, se produjo una parada técnica a principios de 2010, durante la cual la máquina fue preparada para funcionar a más alta energía. Las colisiones de mayor energía requieren mayores corrientes eléctricas en los circuitos de imanes del LHC. Esto representa demandas más exigentes de los sistemas de protección de la nueva máquina, que ahora se han preparado para la tarea.

Una vez que las colisiones a 7 TeV hayan sido establecidas, el plan es funcionar continuamente durante un período de 18 a 24 meses, con una breve parada técnica a finales de 2010. Esto traerá datos suficientes, en todas las áreas de potenciales descubrimientos, para establecer firmemente el LHC como la instalación más importante del mundo en la física de alta energía de las partículas.

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This morning, Friday 19 March at 5:23 AM, the beam energy of the LHCwas ramped to 3.5 TeV, a new world record and the highest energy for this year’s run. Now operators will prepare the machine to make high-energy collisions later this month.

Interview with Alick Macpherson, Engineer in Charge and Mike Lamont, leader of the Operation Group

Produced by: CERN Video Productions
Director: CERN Video Productions

http://teknociencia.es/videos/LHC-sets-new-world-record-at-3-48-TeV-energy-CERN-19-march-2010.flv

LHC sets new world record 30/11/2009

Geneva, 30 November 2009. CERN1’s Large Hadron Collider has today become the world’s highest energy particle accelerator, having accelerated its twin beams of protons to an energy of 1.18 TeV in the early hours of the morning. This exceeds the previous world record of 0.98 TeV, which had been held by the US Fermi National Accelerator Laboratory’s Tevatron collider since 2001. It marks another important milestone on the road to first physics at the LHC in 2010. “We are still coming to terms with just how smoothly the LHC commissioning is going,” said CERN Director General Rolf Heuer. “It is fantastic. However, we are continuing to take it step by step, and there is still a lot to do before we start physics in 2010. I’m keeping my champagne on ice until then.” These developments come just 10 days after the LHC restart, demonstrating the excellent performance of the machine. First beams were injected into the LHC on Friday 20 November. Over the following days, the machine’s operators circulated beams around the ring alternately in one direction and then the other at the injection energy of 450 GeV, gradually increasing the beam lifetime to around 10 hours. On Monday 23 November, two beams circulated together for the first time, and the four big LHC detectors recorded their first collision data. Last night’s achievement brings further confirmation that the LHC is progressing smoothly towards the objective of first physics early in 2010. The world record energy was first broken yesterday evening, when beam 1 was accelerated from 450 GeV, reaching 1050 GeV (1.05 TeV) at 21:48, Sunday 29 November. Three hours later both LHC beams were successfully accelerated to 1.18 TeV, at 00:44, 30 November. “I was here 20 years ago when we switched on CERN’s last major particle accelerator, LEP,” said Accelerators and Technology Director Steve Myers. “I thought that was a great machine to operate, but this is something else. What took us days or weeks with LEP, we’re doing in hours with the LHC. So far, it all augurs well for a great research programme.” Next on the schedule is a concentrated commissioning phase aimed at increasing the beam intensity before delivering good quantities of collision data to the experiments before Christmas. So far, all the LHC commissioning work has been carried out with a low intensity pilot beam. Higher intensity is needed to provide meaningful proton-proton collision rates. The current commissioning phase aims to make sure that these higher intensities can be safely handled and that stable conditions can be guaranteed for the experiments during collisions. This phase is estimated to take around a week, after which the LHC will be colliding beams for calibration purposes until the end of the year.

Produced by: CERN video productions
Director: CERN video productions

http://teknociencia.es/videos/LHC-sets-new-world-record-noviembre-2009.flv

http://press.web.cern.ch/press/PressReleases/Releases2010/PR05.10E.html

The Large Hadron Collider is once again moving into world-record-setting territory as it gears up to smash protons at the unprecedented energy of seven trillion electron volts. As the accelerator gets ready to speed up and smash particles, the LHC experiments—which record and analyze the debris from high-energy collisions—are running through their final checks and preparing to take center stage.

Whenever the first 7 TeV collisions happen, particle physicists from the experiments will proudly show off snapshots of the very first collisions in their detectors. These snapshots, known as event displays, show the information recorded by the massively complex detectors. However, much like a baby’s first ultrasound image, it can be hard to make heads or tails of the physicists’ pictured pride and joy.

Over the next few days, we’ll help you decode ATLAS and CMS event displays, tell pixel detectors from particles, and follow the action in the accelerator with tips on reading LHC Page 1.

What is an event display?

Experiments performed at an accelerator like the LHC use collision event displays to trace the paths of particles produced in a collision. Below is an event display from the Compact Muon Solenoid (CMS) experiment at the LHC. Event displays are very helpful in visualizing specific physical processes and for checking that the detector and software are functioning properly.

Looking at the title and text on this image, we can see that this event occurred on December 14, 2009 at 4:46 a.m. Central European Time. This was the 5,686,693^rd event to be recorded in Run 124120. A run is a period of continuous operation in a given part of the detector.

The fourth line tells you that the energy level of the collision was 2.36 trillion electron volts (TeV). This event is significant in that it produced two muons, making this a possible dimuon event. The path of muons can be very clearly reconstructed in the CMS detector and can be produced in multiple kinds of collision processes.

The two muon paths seen in the detector could be the result of a single heavy particle, such as the J/Psi, decaying, or from two separate particles that each decay into a muon. The paths might also be caused by particles that are not muons but appear identical to muons within the detector. For these reasons, it is impossible to define what a single event is with total certainty. Instead, extensive analyses of multiple events can give physicists the probability of what a given event could be. This is why the event is referred to as a candidate.

Split screens

The event display is divided into different screens that give you different views of the split second when collision occurred and the produced particles travelled through the detector. In this display, there are three screens:

View A: On this screen, labeled Rho Phi, we have a beam’s eye view, looking straight at the central collision point (1). The particle beam is running straight through that central point.

View B: In this view, labeled Rho Z, the beam line (2) is running horizontally through the center of the screen and we can see the three main regions of the CMS detector.

View C: This three-dimensional perspective view allows physicists to rotate the collision event display around an axis. Here the beam line is on a diagonal, running from the upper left to the lower right portion of the screen.

These screens trace the paths of particles from the collision point through the detector. The detector records when and where it makes contact with a particle so that computers can reconstruct the particle’s path after the protons collide. Based on their final destination and movements, physicists can determine what kinds of particles were produced in a collision.

Collision and detector components

Surrounding the central collision point, the detector has three main components that record information about particle travel.

1: Collision point
The collision point, what particle physicists call the interaction point, is where the protons collide. You can orient yourself when looking at each screen by spotting the collision point and imagining where the beam line would pass.

2: Beam line
The beam line is the path that protons travel in opposite directions and into collision. On screen B, arrows represent the movement of protons along the beam line and towards the center of the detector for collision.

3: Silicon tracker
The innermost portion of the detector is the silicon tracker, outlined by a thin green line on screen A and screen B, and within the mesh cylinder in 3D view.

The tracker, which includes the pixel and silicon strip detectors, reconstructs the movement of particles point by point. These points are represented by yellow dots (you can also look at event displays of magnified tracker images). When we connect the dots we can see the particle tracks, represented here by red and green lines, tracing a particle’s trajectory.

The tracker detects charged particles, so the tracks you see in this section come only from particles with a charge, namely muons, electrons, and charged hadrons.

Because of the magnetic field in which the inner detector resides, these particle tracks are curved. From the degree of curvature, physicists learn about the particle’s momentum. Physicists can discern whether a particle’s charge is positive or negative from the direction, clockwise or counterclockwise, of the curve.

The magnetic field can bend the path of particles in some but not all directions. This is one reason why seeing the event from multiple angles is important. In screen A, we can clearly see curved tracks but in screen B they are not visible. The program used to create this display can rotate the angle and axis of the 3D image in view C. Doing so gives physicists a better sense of how the particles travel in space.

4: Calorimeters
The next main components of the detector are the electromagnetic and hadronic calorimeters, referred to by physicists as the ECal and HCal, respectively. When particles strike one or both, they leave an energy deposit. These deposits are represented by the bars (red for ECal and blue for HCal) just outside of the tracker. The height of the bar corresponds to the amount of energy deposited.

Particles that stop in the ECal are generally either electrons or photons. The two can be distinguished by the fact that electrons are charged and leave tracks in the tracker while photons are neutral and generally do not appear in the tracker.

Hadrons pass through the ECal but are stopped in the HCal. Charged hadrons leave tracks in the tracker while neutral hadrons do not.

It is also possible for the tracker or calorimeters to record signals that do not get reconstructed as particle trajectories or energies. Further analysis can help physicists decide whether these signals come from particles or other processes in the detector.

There is another particle that sometimes deposits energy in one or both calorimeters. This particle is the muon.

5: Muon chambers
The third and outermost components of the detector are the muon system’s muon chambers, so named because they are designed to study muons. A muon can pass through the tracker, calorimeters, and solenoid magnet (not visible in the displays but lying just beyond the calorimeters) to reach the muon chambers.

Muon chambers are visible in screen B as red and blue blocks and the chambers through which a muon has passed have been highlighted. On screen C, only those chambers through which a muon has passed are visible.

6: Muons
This event display illustrates a dimuon event or the production of two muons in a collision. The paths of the muons are shown by the thin red lines on each screen. The muons left signals that were reconstructed into tracks in the silicon tracker, deposited a little energy in the calorimeters, and passed through the muon chambers.

For a good summary of the parts of the CMS detector and the particles that pass through them, take a look at the CMS Detector slice.

Interested in learning more about event displays? Check back tomorrow to learn how to decode an event display from CMS’s sister experiment, ATLAS.

by Daisy Yuhas

http://www.symmetrymagazine.org/

LHCb Experiment

Experimento Atlas

ATLAS Experiment – Footages

CMS Experiment – Footages

ALICE Experiment – Footages

Interview with Karsten Eggert, introduction to TOTEM experiment, CERN

‘Explanation for the general public of the TOTEM detector (Total Cross Section, Elastic Scattering and Diffraction Dissociation) in the LHC tunnel, in particular the Roman Pots at LHC P5 and brief introduction to its main scientific objectives.’

The LHCb Experiment

Roger Forty, CERN’s deputy spokesperson for the LHCb project, points to the inner workings of his team’s detector at the Large Hadron Collider.

Las Catedrales de la Ciencia
Intervention of
John Ellis Theoretical Physicist
Alvaro de Rujula Theoretical Physicist
Robert Aymar General Director of CERN
Mike Lamont Experimental Physicist LHC
Jean-Luc Baldy Civil Engineering
Michel della Negra CMS experiment Project Director
Jurgen Schukraft ALICE experiment Project Director
Tatsuya Nakada LHCb experiment Project Director
Fabiola Gianotti ATLAS experiment Research Physicist
Rolf Landua ATHENA experiment Research Physicist
Juan Antonio Rubio Director for ETT unit
Robert Cailliau Co-developer of WWW
Francois Grey Information Technology Department
Sergio Giacoletto Oracle (Europe) Executive Vice President.