110814792
Design of the MI40 beam-abort dump
A beam-abort dump for the Fermilab Main Injector to handle 3E13 protons per pulse at 150 GeV has been designed. A 120 GeV beam line goes through the beam-dump off-set by 27 cm from its center. The design and the environmental safety aspects of the beam-dump are described here.
135693994
Cryogenic Tests of Glass-Epoxy-Based Electrical Insulation
A thin, superconducting solenoid for the Time Projection Chamber (TPC) experiment at PEP was constructed at Lawrence Berkeley Laboratory (LBL) in 19791 and tested in 1980. A failure of the ground plane insulation damaged the coil to the point that it required rebuilding. An extensive study of this failure2 indicated that an iron chip embedded in the bore tube had penetrated the insulation. Before rebuilding the coil, the insulation system was investigated with the goal of determining the most reliable techniques and materials for withstanding high voltages in the coil package.
35394655
Magnetic field measurements of Fermilab main injector dipoles
Measurements of the Fermilab Main Injector dipoles using a partially redundant system of integrated and point measurements were carried out for quality assurance. Additional special measurements studied the hysteretic field strength. Results from these measurements are presented.
54609000
Strength and shape of the magnetic field of the Fermilab Main Injector dipoles
Measurements of 230 6-meter and 136 4-meter dipoles constructed for the Fermilab Main Injector were carried out as part of the magnet production effort. An automated measurement system provided data on magnetic field strength and shape using several partially redundant systems. Results of these measurements are available for each individual magnet for use in accelerator modelling. In this report we will summarise the results on all of the magnets to characterise the properties which will govern accelerator operation.
28650811
Crossing intrinsic depolarizing resonances by varying a partial Siberian snake.
We recently forced a 140 MeV polarized proton beam to cross intrinsic depolarizing resonances by varying a partial Siberian snake{close_quote}s strength for different values of the vertical and horizontal betatron tunes {nu}{sub {ital y}} and {nu}{sub {ital x}}. A weak second-order intrinsic resonance was observed in the {nu}{sub {ital x}} sweep; moreover, an unexpected partial spin flip was found in the {nu}{sub {ital y}} sweep. We also varied the snake ramp time to identify the {nu}{sub {ital y}} and {nu}{sub {ital x}} regions where the resonance crossings occurred during the snake variation; in these crossings the polarization partially deviated from Froissart-Stora behavior. {copyright} {ital 1996 The American Physical Society.}
122534152
Doubler system quench detection threshold
The experimental study leading to the determination of the sensitivity needed for protecting the Fermilab Doubler from damage during quenches is presented. The quench voltage thresholds involved were obtained from measurements made on Doubler cable of resistance × temperature and voltage × time during quenches under several currents and from data collected during operation of the Doubler Quench Protection System as implemented in the B-12 string of 20 magnets. At 4kA, a quench voltage threshold in excess of 5.0V will limit the peak Doubler cable temperature to 452K for quenches originating in the magnet coils whereas a threshold of 0.5V is required for quenches originating outside of coils.
14737332
The SUGRA Quintessence Model Coupled to the MSSM
We study the cosmological evolution of the universe when quintessence is modeled within supergravity, supersymmetry is broken in a hidden sector, and we also include observable matter in a third independent sector. We find that the presence of hidden sector supersymmetry breaking leads to modifications of the quintessence potential. We focus on the coupling of the SUGRA quintessence model to the MSSM and investigate two possibilities. First one can preserve the form of the SUGRA potential provided the hidden sector dynamics is tuned. The currently available limits on the violations of the equivalence principle imply a universal bound on the vacuum expectation value of the quintessence field now, \kappa ^{1/2}Q\ll 1. On the other hand, the hidden sector fields may be stabilised leading to a minimum of the quintessence potential where the quintessence field acquires a mass of the order of the gravitino mass, large enough to circumvent possible gravitational problems. However, the cosmological evolution of the quintessence field is affected by the presence of the minimum of the potential. The quintessence field settles down at the bottom of the potential very early in the history of the universe. Both at the background and the perturbation levels, the subsequent effect of the quintessence field is undistinguishable from a pure cosmological constant