125921586
Experiment on the fast beam-ion instability at the TRISTAN AR
122772838
Test results of a single aperture 10 tesla dipole model magnet for the Large Hadron Collider
A single aperture dipole magnet has been developed with a design magnetic field of 10 tesla by using Nb-Ti/Cu conductor to be operated at 1.8 K in pressurized super fluid helium, The magnet features double shell coil design by using high keystone Rutherford cable and compact non-magnetic steel collars to be adaptable in split/symmetric coil/collar design for twin aperture dipoles. A design central magnetic field of 10 tesla has been successfully achieved in excitation at 1.95 K in pressurized superfluid helium. Test results of the magnet with a summary of the design and fabrication are presented.
117037168
Testing of TRISTAN insertion quadrupole magnet in superfluid helium
523124
Development of a 56 mm aperture superconducting dipole model magnet for LHC
A 56 mm single aperture superconducting dipole model magnet, which is one of the frameworks of the LHC collaboration between KEK and CERN, has been developed. A central field of 8.65 T is provided at a load line ratio of 90% with a 5 block coil wound with NbTi superconducting cables. The magnet has a straight section of 0.8 m and a total length of 1.2 m. The distinctive features of the magnet are a magnetically symmetrical configuration being applicable to the twin aperture magnet and mechanical consideration sharing the magnetic forces with a high manganese steel collar and a horizontally split iron yoke. The magnet showed almost no training at 4.4 K. The first quench current at 1.8 K was 91% of the short sample I/sub c/ and the magnet reached a central magnetic field of 8.8 T. Finally it could be excited with the current of more than 99% of the short sample limit which corresponds to a central field of 9.63 T.
42191029
Multipole analysis for absolute magnetic field measured by multi-probe pulsed-NMR method
For accelerator dipole magnets, the study on multipole coefficients in a local region is useful for understanding magnet characteristics and checking construction procedure. The multi-probe pulsed-NMR method is a candidate for measurement of the local multipole coefficients. For the absolute fields measured by the multi-probe pulsed-NMR method, a rigorous application of the Fourier expansion is found to yield multipole coefficients. It is made clear that the direction of the dipole field is unable to be determined by the Fourier expansion alone. For estimating alignment accuracy of pulsed-NMR probes, the relationship between errors of multipole coefficients and those of probe position is derived by the Fourier expansion method. For applying of multi-probe pulsed-NMR method to accelerator dipole magnets, we designed and fabricated a field measuring system using two probes. The probes had NMR coils wound around glass ampoules with a diameter of about 1.4 mm. The NMR signal was processed with a phase lock loop circuit to produce the NMR frequency. Dipole field uniformity and multipole coefficients were measured at 0.35 T for a 1.5 m long dipole magnet. It was confirmed that the field data by this NMR system had an accuracy of 10/sup -6/.
125636037
TEST OF THE DELAY LINE FOR Z READOUT OF THE TOPAZ INNER DRIFT CHAMBER
119388026
An observation of the SQS mode in a gas counter
Abstract The SQS mode has been observed with α-rays and a counter using 25 μm thick anode wire for comparatively simple gases, 95% Ar + 5% CO 2 , 90% Ar + 10% CH 4 , CO 2 , CH 4 and iso-C 4 H 10 . The curves of gas multiplication are presented.
118484674
Trapped, Two-Armed, Nearly Vertical Oscillations in Disks with Toroidal Magnetic Fields
We have examined the trapping of two-armed (m = 2) nearly vertical oscillations (vertical p-mode) in vertically isothermal (cs = const.) relativistic disks with toroidal magnetic fields. The magnetic fields are stratified so that the Alfven speed, cA, is constant in the vertical direction. The ratio c 2 A =c 2 in the vertical direction is taken to be a parameter that examines the effects of magnetic fields on wave trapping. We find that the two-armed nearly vertical oscillations are trapped in the inner region of the disks, and their frequencies decrease with an increase of c 2 A =c 2 s . The trapped regions of the fundamental (n = 1) and the first-overtone (n = 2) are narrow (less than the length of the Schwarzschild radius, rg), and their frequencies are relatively high (on the order of the angular frequency of disk rotation in the inner region). In contrast to this, the second overtone (n = 3) is trapped in a wide region (a few times rg), and the frequencies are low and tend to zero in the limit of c 2 A =c 2 s = 2.0.
123323389
Multiwire Proportional Chambers in a 1 GeV/c Magnetic Spectrometer
A set of four multiwire proportional chambers with 612 wires has been constructed for an experiment on proton Compton scattering and π0 photoproduction with the 1.3 GeV electron synchrotron at Institute for Nuclear Study, University of Tokyo. It is located inside the 1 GeV/c Magnetic Spectrometer together with the wire spark chambers. Precise particle trajectories against a high background can be determined by the use of the multiwire proportional chambers. The construction of the chambers and electronics, and the performance of the system are described.
55477539
An idea of dynamical cooling of electron beam in SR ring
A beam cooling method which uses a stimulated emission of radiation by relativistic electrons in a magnetic field, is proposed to apply to an electron beam in synchrotron radiation rings. The simulation is produced by a traveling RF electric field in a transmission line against the beam. Averaging the emission power over electron energy distributions, the net emission from the beam is taken place in a certain frequency region. Some conditions for the energy emission are discussed. The emission power is shown to be enough large to decrease the horizontal emittance of the beam to a very small value in typical synchrotron radiation rings.<<ETX>>
124431523
Strong-interaction form factor of proton in high-energy proton-proton elastic scattering
SummaryAn analysis of high-energy proton-proton elastic-scattering data is made in terms of one-particle exchange type amplitude. The results show that the proton form factor is constant at large momentum transfer. This may be interpreted as evidence for the existence of a pointlike core in the proton.RiassuntoSi esegue un'analisi dei dati dello scattering elastico protone-protone di alte energie in termini dell'ampiezza del tipo dello scambio di una particella. I risultati mostrano che il fattore di forma del protone è costante a grande trasferimento di impulso. Questo può essere interpretato come prova dell'esistenza di un nocciolo puntiforme nel protone.РезюмеВ терминах амплитуды с одно-частичным обменом проводится анализ данных по протон-протонному упругому рассеянию при высоких энергиях. Полученные результаты показывают, что протонный форм-фактор является постоянным при больших передаваемых импульсах. Это можно интерпретировать, как подтверждение существования точечной сердцевины в протоне.