136709664
SCMAG series of programs for calculating superconducting dipole and quadrupole magnets
94844521
ACTIVE CENTER TAP QUENCH PROTECTION
24392991
The Engineering Design of the 1.5 m Diameter Solenoid for the MICE RFCC Modules
The RF coupling coil (RFCC) module of MICE is where muons that have been cooled within the MICE absorber focus (AFC) modules are re-accelerated to their original longitudinal momentum. The RFCC module consists of four 201.25 MHz RF cavities in a 1.4 meter diameter vacuum vessel. The muons are kept within the RF cavities by the magnetic field generated by a superconducting coupling solenoid that goes around the RF cavities. The coupling solenoid will be cooled using a pair of 4 K pulse tube cooler that will generate 1.5 W of cooling at 4.2 K. The magnet will be powered using a 300 A two-quadrant power supply. This report describes the ICST engineering design of the coupling solenoid for MICE.
118834673
A Design for a Combined Function Superconducting Dipole for a Muon Collider FFAG Accelerator
The acceleration stages for a muon collider require that the muons be accelerated within a given ring in fewer than twenty turns. One type of accelerator that appears to be attractive for a synchrotron that accelerates the muon a factor of four in energy in a few turns is the Fixed Field Alternating Gradient (FFAG) type of accelerator. As the energy of the muon beam increases, the muons move toward a higher field region of a DC combined function dipole. The following dipole and quadrupole magnet characteristics are required for a muon FFAG machine to be successful: (1) The dipole will be a fixed field dipole with an impressed quadrupole and sextupole field. There may or may not be separate quadrupoles that mayor may not have added sextupole windings. (2) The horizontal aperture of the required good field region is wider than the vertical aperture of the required good field region. (3) The magnet is relatively short, so that the conventional SSC type of superconducting dipole or quadrupole ends can not be used. The field at the end of the magnet must fall off abruptly within the distance of less than one vertical aperture. For a magnet that is 400more » mm long, the end region can be no more than 80 mm long. (4) The structure of the integrated field within the end region must be the same as the structure of the two-dimensional filed at the center of the magnet. A very preliminary design concept for a FFAG combined function dipole is presented in this paper.« less
122748175
Calculation of the pressure rise in the cooling tube of a two-phase cooling system during a quench of an indirectly cooled superconducting magnet
Large superconducting detector magnets are indirectly cooled with two-phase helium flowing in cooling tubes attached to the coil or its support structure. Large detector magnets often quench such that most of the magnet stored energy ends up as heat stored in the coil package. The time constant for energy deposition in the coil and support structure is often quite short. This paper presents a method for calculating the peak pressure rise in the magnet two-phase cooling tube during a magnet quench. A comparison of calculated peak pressure rise and measured pressure rise for the PEP-4 solenoid is presented in this report. >
123081787
PROGRESS ON THE SUPERCONDUCTING MAGNET FOR THE TIME PROJECTION CHAMBER EXPERIMENT (TPC) AT PEP
The TPC (Time Projection Chamber) experiment at PEP will have a two meter inside diameter superconducting magnet which creatests a 1.5 T uniform solenoidal field for the TPC. The superconducting magnet coil, cryostat, cooling system, and the TPC gas pressure vessel (which operatests at 11 atm) were designed to be about two thirds of a radiation length thick. As a result, a high current density coil design was chosen. The magnet is cooled by forced flow two phase helium. The TPC magnet is the largest adiabatically stable superconducting magnet built to date. The paper presents the parameters of the TPC thin solenoid and its subsystems. Tests results from the Spring 1980 cryogenic tes are presented. The topics to be dealt with in the paper are cryogenic services and the tests of magnet subsystems such as the folded current leads. Large thin superconducting magnet technology will be important to large detectors to be used on LEP.
122251395
Average properties of dual resonances
Abstract As a consequence of the strong interaction (A.F.S.) scaling of dual amplitudes, we find that the average total width of a high mass resonance approaches a constant which is less than 1/π(GeV) 2 . We also obtain a logarithmic increase of the average multiplicity coming from the decay of dual resonances.
14956761
The Low-energy expansion of the one loop type II superstring amplitude
The one-loop four-graviton amplitude in either of the type II superstring theories is expanded in powers of the external momenta up to and including terms of order s^4 log s R^4, where R^4 denotes a specific contraction of four linearized Weyl tensors and s is a Mandelstam invariant. Terms in this series are obtained by integrating powers of the two-dimensional scalar field theory propagator over the toroidal world-sheet as well as the moduli of the torus. The values of these coefficients match expectations based on duality relations between string theory and eleven-dimensional supergravity.
18544496
Speculations on AdS/CFT at all orders in 1/N
A simple ansatz is considered for the scalar field dependence of the part of the fourgraviton scattering amplitude in type IIB superstring theory in AdS5 × S that comes from the (Weyl tensor) term. This incorporates SL(2, ZZ) duality at every order of the α/L expansion (where L is the AdS5 scale). The relative coefficients in this series are determined, via the AdS/CFT correspondence, by the contribution of a single Yang–Mills instanton to the correlation function of four energy-momentum tensors in the N = 4 SU(N) Yang–Mills theory, which is known exactly for all values of N . The resulting series is not Borel summable, which suggests that some puzzling contributions that are nonperturbative in α/L = (g Y M N) (where g Y M is the Yang–Mills coupling constant) may be present in the complete expression.
123045249
The insertion of boundaries in world-sheets
Abstract This paper considers the operator that inserts a boundary in a string world-sheet on which the string coordinates satisfy either Neumann or constant Dirichlet boundary conditions. With an arbitrary open-string state attached to the boundary, this describes the vertex coupling an open string to a closed string (the “open-closed string vertex”). A boundary with no open strings attached can be viewed as a vacuum correction to closed-string theory. This factories into two open-closed string vertices joined together by an open-string propagator. BRST-invariant open-closed string vertices of the Neumann and Dirichlet theories are constructed in a “light-cone-like” frame (familiar from some formulations of covariant string field theory) as well as the “vertex operator” frame (in which a general open-string state is represented by a vertex operator attached to the world-sheet boundary). The vertices of the Neumann and Dirichlet theories are related to each other by space-time duality. The insertion of a closed Dirichlet boundary may be expressed in the light-cone-like gauge as an interaction vertex that acts at a fixed “time” and generates an explicit mass term connecting two arbitrary closed-string states. Some examples of how the presence of such boundaries modifies amplitudes for low-lying states are presented.
120397444
The inclusion of fermions in dual N-point functions
Abstract Dual amplitudes of the five-point function for two fermions and three scalar bosons are constructed, and are used to obtain a consistent procedure for inclusing two fermions in the general N -point function.