109198934
A Large Superconducting Detector Magnet Without An Iron Return Path
This paper describes a detector magnet which returns flux between the coils rather than through an iron return path. This actively shielded, uniform field 2 T magnet can be fabricated in separate parts which can be manufactured on the SSC site. This magnet can be built so that central field is uniform enough to permit a TPC detector to be used without iron poles. The field outside of the coil can be made to fall of as R−N power where N approaches 9. A major advantage of the magnet described in the paper is that there is no pole piece to block the particle jets emanating from the collision region in the forward and backward directions. Inexpensive materials such as earth and concrete can be used to provide the mass needed to analyze particles such as mu mesons. As a result, problems such as experimental hall subsidence can be reduced. Perhaps the cost of such an experiment can also be reduced. This type of magnet would require experimenters to rethink their experimental concepts.
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.
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. >
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.
94844521
ACTIVE CENTER TAP QUENCH PROTECTION
122187455
Superfield theory of type (II) superstrings
Abstract Type (II) superstrings are described by light-cone superfields that are functionals of string superspace coordinates x i ( σ ) and ϑ a ( σ ) or the conjugate momenta p i ( σ ) and λ a ( σ ). The interaction hamiltonian and supersymmetry charges are determined to first order in the coupling constant by requiring invariance under the super-Poincare algebra, some of whose generators are implemented locally in σ. In a suitable low-energy limit the formalism goes smoothly into that of extended supergravity in ten dimensions.
120391337
Dynamical point-like structure and dual strings
Abstract The emission of zero momentum scalar particles into the vacuum from dual strings is shown to be equivalent to the insertion of point-like energy densities on the strings. This suggests a physically plausible procedure for modifying the dual model to incorporate point-like structure leading, for example, to power behaved large angle elastic scattering.
122189895
String field theory with chiral coordinates
Interesting string theories, such as the heterotic string, involve chiral coordinates, that is coordinates which are either right-moving or left-moving on the world sheet. In this paper the field theoretic formulation of such theories is studied with most emphasis on the light-cone gauge method although the main techniques would also apply in the various covariant approaches to string field theory. In the heterotic string the internal symmetry is described in terms of eight left-moving complex bosonic coordinates in a manner which parallels the treatment of fermionic Grassmann coordinates. The wave functions, and hence the free string fields, are described in these coordinates and the three-string interaction is derived from the requirements of supersymmetry and Lorentz invariance both in its functional form and in terms of its oscillator modes.
120850184
Dynamically based coupling scheme for the Pomeranchukon
120524357
Point-like particles and off-shell supersymmetry algebras
Abstract The reparametrization invariant action, describing supersymmetric particles, is shown to have a non-local symmetry and consequently an enlarged, N = 2, supersymmetry invariance with a central charge. The construction of multiplets of states only involves physical operators - there are no auxiliary states in the theory, even though the supersymmetry algebra applies off-shell. The free field action is described in terms of superfields which are Clifford operators. Comments are made about analogous string theories.