Disassociation of Electrons From Partially Stripped Ion Beams Due to Strong Magnetic Fields

We study the probability of dissociating an electron from partially stripped ions in the AGS. Our calculation indicates that the probability for electron disassociation due to the strong external magnetic field in the AGS is very small for tightly bounded electrons. Two methods are used to estimate this effect: a one-dimensional JWKB method; an energy density approximation. Both methods yield a consistent picture to support the idea of accelerating the partially stripped ions in the AGS, which requires some upgrade in the vacuum pressure due to other processes such as electron capture and ionization. 5 refs., 4 figs

Energy upgrade as regards quench performance

Since the cross section for W production increases rapidly with energy, we consider the possibility of increasing the collision energy of polarized protons at RHIC. The limits of present hardware are examined with a particular emphasis on the quench training performance of magnets. Ignoring the limits of the DX magnets, the short-sample currents for the main arc (8 cm) dipoles could allow an increase of more than 30%, however we estimate 400 to 500 training quenches for the just 8 cm dipoles to reach this level. We propose that a 10% increase in energy might be achieved with the present hardware configuration. Raising the beam energy to 275 GeV ({radical}s = 550 GeV) should increase the W production rate by almost 50% from the 250 GeV level for the same optics with identical {beta}*'s at the collision points

Analytic method for spin transfer matrix in presence of snakes

Large accelerators can be made spin transparent using Siberian snakes. However, the number of snakes required is yet to be determined. An algorithm for finding the spin transfer matrix analytically is developed. This is applied to find the cos /sub p/ for the case involving 6 snakes in two different configurations. This is in contrast to R. Ruth's approach who found that the number of snakes is proportional to absolute value of epsilonS, where epsilon is the depolarizing resonance strength. Half the trace of the spin precession matrix with 6 equally spaced snakes is found analytically for two configurations. The first configuration involves alternating snakes with precession axes of +45 and -45 while the second configuration are alternating +75 and -75 as proposed by K. Steffen. Then the largest resonance strength absolute value of epsilon such that absolute value of cos /sub p/ less than or equal to less than or equal to 1 is determined. Finally, a comparison with tracking studies is made

BNL-built LHC magnet error impact analysis and compensation

Superconducting magnets built at the Brookhaven National Laboratory will be installed in both the Insertion Region IP2 and IP8, and the RF region of the Large Hadron Collider (LHC). In particular, field quality of these IR dipoles will become important during LHC heavy- ion operation when the beta * at IP2 is reduced to 0.5 meters. This paper studies the impact of the magnetic errors in BNL-built magnets on LHC performance at injection and collision, both for proton and heavy-ion operation. Methods and schemes for error compensation are considered including optimization of magnet orientation and compensation using local IR correctors. (2 refs)