Synchrotron, proton

X-radiation can also be induced by high energy (several Me proton beams from ion accelerators. Such particle-induced x-ray emission (PIXE) (284) is useful for thin samples and particulates, having detection Hmits of g. Intense synchrotron x-ray sources have found appHcations in... 

The Cockroft-Walton and Van de Graaff accelerators are linear that is, they accelerate particles in a straight line. A short time later Ernest Lawrence got the idea to build a circular accelerator, called a cyclotron, and with the help of M. Stanley Livingston he constructed it in 1932. This first cyclotron accelerated protons to about 4 MeV. Since then, many other cyclotrons have been built, and they have been used to accelerate particles to more than 50 times as much kinetic energy as the original one. Also, other kinds of circular accelerators, such as synchrotrons, have been constructed. 

Synchrotron radiation is not a serious problem for proton synchrotrons, but it is for high energy electron synchrotons because the mass of the electron is... 

Janssens, K., Aerts, A., Yincze, L., et al. (1996). Corrosion phenomena in electron, proton and synchrotron X-ray microprobe analysis of Roman glass from Qumran, Jordan. Nuclear Instruments and Methods B 109-110 690-695. 

In 2006, Lobinski et al.1 reported on the imaging and speciation analysis of trace elements to study the element distribution, oxidation state, metal site and metal structure in biological environments using mass spectrometric techniques (LA-ICP-MS, SIMS, MALDI-MS) and non-mass-spectrometric techniques such as micro-PIXE (proton induced X-ray emission), XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure) -the latter two techniques are very sensitive due the use of a more intense synchrotron beam.1... 

Fig. 5. An early fixed-target accelerator comprised of a laige main-ring synchrotron with four stages of acceleration (MRA) a booster synchrotron a linear accelerator (linac), and a Cockcroft-Walton generator. Pistons aie accelerated to 0, 5 MeV in the Cockcroft-Walton generator to 300 MeV in the linac to 8 GeV in the booster synchrotron, and to 400-500 GeV in the mam-ring synchrotron. Experiments are not limited to accelerated protons, but also can be conducted with beams of secondary particles (mesons and neutrinos) which are knocked out of the target by impacting protons...

Once more the development undergone between 1948 and 1961 by the experimental techniques as well as by the theoretical interpretation of subnuclear particles was amazing. In 1952, at the Brookhaven National Laboratory, the first proton synchrotron, the Cosmotron, entered into operation. It produced protons of energies up to 3.2 GeV, and became immediately a controlled source of pions and strange particles of much higher intensity than cosmic rays. 

Nuclear properties (spins, moments, charge radii) revealed by the analysis of hyperfine structure and isotope shift of atomic levels have been obtained in decades of experiments. Since 1975 with the introduction of tunable dye laser, the rebirth of the methods, some already known since 1930, had led to many on line experiments on short lived isotopes not investigated before. I report here a sample of the experiments done by the Orsay, Mainz groups at CERN. Although experiments have been carried out by the Orsay group using the proton beam of the CERN Proton Synchrotron, most of the experiments have been done at Isolde, the on - line mass separator at CERN, whose radioactive beams are essential to the success of these experiments [RAV 84]. 

The rest of the apparatus is the same as when operated at the Proton Synchrotron. First tested on cesium [ HUB 78 ], [ THI 81 ] the apparatus was used to uncover the resonance lines of francium for which no optical transition had ever been observed. The CERN on line mass separator, Isolde, makes available a source of more than 10 atoms/sec of chemically and isotopically pure 213 Fr isotope. Such an amount is more than needed for a laser atomic beam spectroscopy. The first step is obviously to locate the resonance line at low resolution, using a broad band laser excitation. In a second step, once the line is located, a high resolution study is undertaken, [ LIB 80] and [ BEN 84]. The observed signal is displayed (fig 3a) at low resolution and(3 b)at high resolution. 

The experiment on the observation of 7r+7r- atoms was carried out at the 70 GeV proton synchrotron (U-70) at Serpukhov [31,32]. Pionic atoms and 7r+7r pairs ( free pairs) were produced in a 8pm thick tantalum target ( thick target) inserted into the internal proton beam. The atoms can either annihilate into 7r°7r° pairs or break up (ionize) into 7r+7r pairs ( atomic pairs) inside the same target. The free and atomic pairs get into the 40 m long vacuum channel (the acceptance is 3.8 10-5 sr) at 8.4° to the proton beam and are detected by the setup in the 0.8 4- 2.4GeV/c pion momentum interval. 

Using the high intensity pulsed muon beam from the Rutherford Laboratory 1 GeV proton synchrotron, the Heidelberg group has initiated a new experiment... 

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