新华网日内瓦6月23日电(记者张淼 王昭)欧洲核子研究中心23日发布新闻公报说，目前全球最大、能量最高的粒子加速器——欧洲大型强子对撞机重启准备工作已经开始，按计划对撞机将于2015年初恢复运行。

　　公报称，为准备重启，对撞机的冷却工作已开始，目前对撞机约八分之一部分已冷却至运行温度。本月18日，对撞机内部的质子同步加速器已重启。

　　公报称，在过去16个月中，大型强子对撞机与欧洲核子研究中心其他加速器经历了维修与升级，为保证对撞机重启后按预期能量运行，已在对撞机内部巩固了1万个超导磁体。按目前规划，对撞机重启后产生的质子束流能量将是此前运行阶段的约两倍。

　　“在经历重要‘外科手术’后，大型强子对撞机正从长时间休眠中苏醒，”欧洲核子研究中心科技和加速器项目主任弗雷德里克·博尔德里说，“我们正在小心唤醒它，争取在明年初对撞实验开始前进行诸多测试，2015年的目标是以13万亿电子伏特的质子束流能量进行实验。”

　　公报称，大型强子对撞机在首阶段运行中以7万亿至8万亿电子伏特的能量进行对撞实验，重启后对撞机可能会产生更高的质子束流能量，这将有助于科学家深入研究“上帝粒子”希格斯玻色子，为解开暗物质之谜等开启新窗口。

　　欧洲大型强子对撞机于2008年9月建成运行，首阶段运行于2012年末结束。大型强子对撞机可模拟宇宙大爆炸后的宇宙初期形态，帮助科学家研究宇宙起源和寻找新粒子。

　　来源：新华网 

　　CERN announces LHC restart schedule

　　The Large Hadron Collider is being prepared for its second three-year run (Image: CERN) 

　　The Large Hadron Collider (LHC), the largest and most powerful particle accelerator in the world, has started to get ready for its second three-year run. Cool down of the vast machine has already begun in preparation for research to resume early in 2015 following a long technical stop to prepare the machine for running at almost double the energy of run 1. The last LHC magnet interconnection was closed on 18 June 2014 and one sector of 1/8 of the machine has already been cooled to operating temperature. The accelerator chain that supplies the LHC’s particle beams is currently starting up, with beam in the Proton Synchrotron accelerator last Wednesday for the first time since 2012.

　　"There is a new buzz about the laboratory and a real sense of anticipation," says CERN Director General Rolf Heuer, speaking at a press conference at the EuroScience Open ForumExternal Links icon (ESOF) meeting in Copenhagen. "Much work has been carried out on the LHC over the last 18 months or so, and it’s effectively a new machine, poised to set us on the path to new discoveries."

　　Over the last 16 months, the LHC has been through a major programme of maintenance and upgrading, along with the rest of CERN’s accelerator complex, some elements of which have been in operation since 1959. Some 10,000 superconducting magnet interconnections of were consolidated in order to prepare the LHC machine for running at its design energy.

　　"The machine is coming out of a long sleep after undergoing an important surgical operation," says Frédérick Bordry, CERN’s Director for Accelerators and Technology. "We are now going to wake it up very carefully and go through many tests before colliding beams again early next year. The objective for 2015 is to run the physics programme at 13 TeV."

　　The LHC experiments also took advantage of this long pause to upgrade their particle detectors. "The discovery of a Higgs boson was just the beginning of the LHC’s journey," said senior CERN physicist Fabiola Gianotti at the same press conference. "The increase in energy opens the door to a whole new discovery potential."

　　The Higgs boson, first mentioned in a 1964 paper by Peter Higgs, is linked to the mechanism, proposed the same year by Higgs and independently by Robert Brout and François Englert, that gives mass to fundamental particles. During its first three years, the LHC ran at a collision energy of 7 to 8 TeV delivering particle collisions to four major experiments: ATLAS, CMS, ALICE and LHCb. With the large amount of data provided by the LHC during this first period, the ATLAS and CMS experiments were able to announce the discovery of the long-sought Higgs boson on 4 July 2012, paving the way for the award of the 2013 Nobel Prize in physics to theorists François Englert and Peter Higgs.

　　By providing collisions at energies never reached in a particle accelerator before, the LHC will open a new window for potential discovery, allowing further studies on the Higgs boson and potentially addressing unsolved mysteries such as dark matter. The ordinary matter of which we, and everything visible in the universe is composed, makes up just 5% of what the universe is made of. The remainder is dark matter and energy, so the stakes for LHC run 2 are high.

　　CERN’s accelerator complex: Restart schedule 

　　2 June 2014 Restart of the Proton Synchrotron Booster

　　18 June 2014 Restart of the Proton Synchrotron (PS)

　　Early July Powering tests at the Super Proton Synchrotron (SPS)

　　Mid-July Physics programme to restart at the ISOLDE facility and at the PS

　　Mid-August Antimatter Physics programme to restart at the Antiproton Decelerator

　　Mid-October Physics programme to restart at the SPS

　　Early 2015 Beam back into the Large Hadron Collider (LHC)

　　Spring 2015 Physics programme to restart at the LHC experiments

　　Source：home.web.cern.ch