Results from the CERN pilot CLOUD experiment

During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm -3 s -1, and growth rates between 2 and 37 nm h -1. The corresponding H2O concentrations were typically around 106 cm -3 or less. The experimentally-measured formation rates and htwosofour concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 °C

LHC: AN EXCITING PHYSICS FUTURE FOR CERN<BR>Lecture 1 - An introduction to structures on all scales

Starting from a discussion of the smallest constituents of matter to the largest structures in the universe, this 3 lecture series will review the successes of LEP and show how they open the door to an exciting programme of physics at the LHC. These open lectures are targetted at people who have a scientific, engineering or technical background but are not specialists in the field of particle physics. Anyone who is curious about CERN physics and its future will find something of interest

LHC: AN EXCITING PHYSICS FUTURE FOR CERN<BR>Lecture 2 - What we have learned from LEP

These open lectures are targetted at people who have a scientific, engineering or technical background but are not specialists in the field of particle physics. Anyone who is curious about CERN physics and its future will find something of interest. Lecture 1 - An introduction to structures on all scales is now available for viewing on the web at http://wlap.web.cern.ch/</A href

Thorium Energy for the World

The Thorium Energy Conference (ThEC13) gathered some of the world’s leading experts on thorium technologies to review the possibility of destroying nuclear waste in the short term, and replacing the uranium fuel cycle in nuclear systems with the thorium fuel cycle in the long term. The latter would provide abundant, reliable and safe energy with no CO2 production, no air pollution, and minimal waste production. The participants, representatives of 30 countries, included Carlo Rubbia, Nobel Prize Laureate in physics and inventor of the Energy Amplifier; Jack Steinberger, Nobel Prize Laureate in physics; Hans Blix, former Director General of the International Atomic Energy Agency (IAEA); Rolf Heuer, Director General of CERN; Pascal Couchepin, former President of the Swiss Confederation; and Claude Haegi, President of the FEDRE, to name just a few. The ThEC13 proceedings are a source of reference on the use of thorium for energy generation. They offer detailed technical reviews of the status of thorium energy technologies, from basic R&D to industrial developments. They also describe how thorium can be used in critical reactors and in subcritical accelerator-driven systems (ADS), answering the important questions: – Why is thorium so attractive and what is the role of innovation, in particular in the nuclear energy domain? – What are the national and international R&D programs on thorium technologies and how are they progressing? ThEC13 was organized jointly by the international Thorium Energy Committee (iThEC), an association based in Geneva, and the International Thorium Energy Organisation (IThEO). It was held in the Globe of Science and Innovation at the European Organization for Nuclear Research (CERN), Geneva, Switzerland, in October 2013