118036529
Operational experience with the CERN hadron linacs
A screw supply control apparatus controls screw-feed operations of a screw feeder which sequentially supplies to a robot a plurality of screws. The apparatus includes a screw feeder having a screw air-feed pipe through which the screws are air-fed to the robot, and an air-feed valve provided to the screw air-feed pipe. Compressed air is fed into the screw air-feed pipe to air-feed the screw when the screw air-feed valve is open whereas compressed air is not fed into the screw air-feed pipe when the screw air-feed valve is closed. A screw passage sensor is provided at the screw air-feed pipe for sensing passage of the screw and produces a passage signal when the passage of the screw is sensed. A monostable multivibrator is provided for measuring a predetermined period of time and produces a time-up signal when the predetermined period of time is measured. A control unit controls the air-feed valve to open in response to the passage signal and then to close the air-feed valve in response to the time-up signal wherein the monostable multivibrator is controlled to start measurement of the predetermined period of time when the screw passage sensor produces the passage signal.
55729922
Experiments on a 14.5 GHz ECR Source
A device for measuring the speed of the wind at medium altitude by the Doppler effect within the visible frequency range comprises a laser which emits pulses of light, a telescope which receives a scattered light and an interferometer used to measure the spectral shift of the scattered light in relation to the emitted pulse of light. The interferometer is a Fabry-Perot interferometer in which a part of one of the two mirrors of the interferometer is covered with an excess thickness of silica to form two separate filters. The spacing of the two mirrors and the excess thickness of silica are determined in such a manner that the pass bands of each one of the two filters thus constructed are centered on the flanks of the spectral distribution of the backscattered light.
102555920
The LHC Lead Ion Injector Chain
115300845
Status and first beam measurements on the CERN RFQ
119401628
The Electron Cooling Device for LEAR
The experiments1,2,3 in which low energetic protons were cooled by a “cold” electron beam have proved that this method is a very powerful technique to improve low energy beams and to increase their phase space density by several orders of magnitude in short times. The theoretical understanding of the cooling process is well advanced4,5,6. The applications of this technique, which was invented and developed in Novosibirsk, are manifold7. It seems to be clear that its main domain is the cooling of non-relativistic ions. However, also at extremely high energies, cooling of protons and antiprotons with stored electrons (cooled themselves by synchrotron radiation) can be contemplated8,9.
121894301
Studies on ECR4 for the CERN ion program
The CERN heavy ion community, and some other high energy physics experiments, are starting to demand other ions, both heavy and light, in addition to the traditional lead ions. Studies of the behavior of the afterglow for different operation modes of the ECR4 at CERN have been continued to try to understand the differences between pulsed afterglow and continuous operation, and their effect on ion yield and beam reproducibility. The progress in adapting the source and ion beam characteristics to meet the new demands will be presented, as will new information on voltage holding problems in the extraction.
122678636
One Loop Operator Matrix Elements in the Unruh Vacuum
Abstract We present the details of a study of the matrix elements of local operators in the Unruh vacuum for real massive scalar fields in arbitrary d -spatial dimensions (also the Casimir effects for an infinite plane conductor). This state produces negative expectations for renormalized operators such as φ 2 and T μν with the structure of thermal corrections where the temperature is a local Hawking temperature. We trace this to the lack of precise boundary conditions for the theory on the horizon. Though the Minkowski vacuum appears to be populated with Rindler particles, it produces the general coordinate transform of the Minkowski results as dictated by general covariance. A simple corollary is that broken symmetries are not seen to be restored at large acceleration; the dynamical interpretation of this fact by the accelerating observer is surprising.
121301170
Calculable nonminimal coupling of composite scalar bosons to gravity
The nonminimal coupling to gravity −ξRφ22 of a composite scalar field φ is calculated in the Nambu-Jona-Lasinio model. We find ξ = 16. The result is exact in a leading large-N approximation, or in a fully improved one-loop renormalization group approximation. We briefly discuss some related cosmological implications.
125438498
Top quark mass measurements
The top quark, with its extraordinarily large mass (nearly that of a gold atom), plays a significant role in the phenomenology of EWSB in the Standard Model. In particular, the top quark mass when combined with the W mass constrains the mass of the as yet unobserved Higgs boson. Thus, a precise determination of the mass of the top quark is a principal goal of the CDF and D0 experiments. With the data collected thus far in Runs 1 and 2 of the Tevatron, CDF and D0 have measured the top quark mass in both the lepton+jets and dilepton decay channels using a variety of complementary experimental techniques. The author presents an overview of the most recent of the measurements.
15892931
Gauge coupling unification with extra dimensions and gravitational scale effects
Abstract We study gauge coupling unification in the presence of extra dimensions compactified at a few TeV. Achieving unification requires a large number of gauge boson Kaluza–Klein excitations lighter than the string scale, such that the higher-dimensional gauge couplings are O (1) in string scale units. Corrections to the gauge couplings from two or more loops are about 10% or larger, hence string (or M) theory is generally expected to be strongly coupled in ∼TeV-scale extra-dimensional scenarios. Higher-dimensional operators induced by quantum gravitational effects can shift the gauge couplings by a few percent. These effects are sufficiently large that even the minimal Standard Model, or the MSSM, allow unification at a scale in the ∼TeV range. The strongly coupled unified theory may induce dynamical electroweak symmetry breaking.
111000899
Operational experience and performance of the CDFII silicon detector
The CDFII silicon detector consists of 8 layers of double-sided silicon micro-strip sensors totaling 722,432 readout channels, making it one of the largest silicon detectors in present use by an HEP experiment. After nearly 2 years of data taking, we report on our experience operating the complex device. The performance of the CDFII silicon detector is presented and its effect on physics analyses is discussed. The CDFII silicon detector has begun to show measurable effects of radiation damage. These results and their impact on the expected lifetime of the detector are briefly reviewed.