119539356
The PEP II injection kicker system
PEP II or the B-Factory consists of two asymmetric storage rings. The injection energy for electrons is 9 GeV, while that for positrons is 3.1 GeV. The bend angle into the high energy ring (HER) is 0.35 m-rad, and the angle into the low energy ring (LER) is 0.575 m-rad. The magnetic length for the HER kicker is 0.85 m, and 0.55 m for the LER kicker. The field produced by the magnet is therefore 123.5 G for the HER, and 132 G for the LER. Each ring has a kicker magnet upstream of the injection line which is used to distort the orbit of the stored beam. An identical magnet downstream of the injection line is used to restore the orbit of the stored beam and inject the incoming beam. The two magnets are driven in parallel by the modulator. The aperture of the magnets is 3.86/spl times/3.46 cm (H/spl times/V). Therefore the current required to drive the HER is 863 A, while for the LER it is 756 A. The inductance of the magnet is approximately 1.4 /spl mu/H/m. The current pulse is a critically damped sinusoid with a rise time of less than 300 ns. A kicker system has been designed which can be used for injection of both beams by varying the charge voltage. The modulator uses a conjugate circuit to match the impedance of the magnet, and coupling to the beam chamber.
109841692
A solid state induction modulator for SLAC NLC
The Next Linear Collider accelerator proposal at SLAC requires a high efficiency, highly reliable, and low cost pulsed-power modulator to drive the 500 KV, 260A X band klystrons. With a pulse width of less than 1.5 microseconds, it is difficult for the present SLAC type modulator with conventional pulse transformer to have a high efficiency due primarily to the inherently slow rise and fall time of the video pulse. The proposed induction modulator utilises a pulse transformer similar to an induction accelerator driven by solid state high voltage IGBTs. The performance of the IGBTs, induction cores and a low voltage model will be discussed as well as the design and construction of a prototype modulator capable of driving up to 8 of the X band klystrons.
15700414
Diagnosing the PEP-II Injection System
The injection of beam into the PEP-II B-Factory, especially into the High Energy Ring (HER) has some challenges. A high background level in the BaBar detector has for a while inhibited us from trickling charge into the HER similar to the Low Energy Ring (LER). Analyzing the injection system has revealed many issues which could be improved. The injection bump between two kickers was not closed, mainly because the phase advance wasn't exactly 180{sup o} and the two kicker strengths were not balanced. Additionally we found reflections which kick the stored beam after the main kick and cause the average luminosity to drop about 3% for a 10 Hz injection rate. The strength of the overall kick is nearly twice as high as the design, indicating a much bigger effective septum thickness. Compared with single beam the background is worse when the HER beam is colliding with the LER beam. This hints that the beam-beam force and the observed vertical blow-up in the HER pushes the beam and especially the injected beam further out to the edge of the dynamic aperture or beyond.
113772275
Update on Kicker Development for the NGLS
The latest requirements for the Next Generation Light Source (NGLS) beam spreader call for a kicker to deflect a 2.6 GeV electron beam by an angle of 0.7 mrad over a length of 1.8 meters. The rise and fall time requirements for the integrated B field are <50 ns, the pulse frequency is up to 100 kHz, and the inter-pulse and pulse to pulse ripple requirements are 0.004 % and <0.01 % respectively of full scale. These requirements, along with the basic design of the beam spreader are still evolving, and several magnet types and modulator topologies have been considered. This paper will discuss this evolution as it pertains to the kickers, what the current status is of the R&D effort, and the plan to build a full power prototype system.
17062817
Solid-State Modulators for RF and Fast Kickers
As the switching capabilities of solid-state devices increase, these devices are being incorporated into modulator designs for high voltage accelerator applications. Solid-state modulators based on inductive adder circuit topology have demonstrated great versatility with regard to pulse width and pulse repetition rate while maintaining fast pulse rise and fall times. Additionally, these modulators are capable of being scaled to higher output voltage and power levels. An explanation of the basic circuit operation will be presented as well as test data of several different hardware systems.
110722988
The prototype solid state induction modulator for SLAC NLC
The Next Linear Collider accelerator proposal at SLAC requires a high efficiency, highly reliable, and low cost pulsed power modulator to drive the X band klystrons. The present NLC envisions a solid-state induction modulator design to drive up to 8 klystrons to 500kV for 3/spl mu/s at 120 PPS with one modulator (>1,000 megawatt pulse, 500kW average). A prototype modulator is presently under construction, which well power 4 each 5045 SLAC klystron to greater than 380kV for 3/spl mu/s (>600 megawatt pulse, >300kW Ave.). The modulator will be capable of driving the 8 each X band klystrons when they become available. The paper covers the design, construction, fabrication and preliminary testing of the prototype modulator.
118302289
Matching of analytical and numerical solutions for neutron stars of arbitrary rotation
We demonstrate the results of an attempt to match the two-soliton analytical solution with the numerically produced solutions of the Einstein field equations, that describe the spacetime exterior of rotating neutron stars, for arbitrary rotation. The matching procedure is performed by equating the first four multipole moments of the analytical solution to the multipole moments of the numerical one. We then argue that in order to check the effectiveness of the matching of the analytical with the numerical solution we should compare the metric components, the radius of the innermost stable circular orbit (RISCO), the rotation frequency and the epicyclic frequencies ??, ?z. Finally we present some results of the comparison.
15957971
Extending Sibgatullin's ansatz for the Ernst potential to generate a richer family of axially symmetric solutions of Einstein's equations
The scope of this talk is to present some preliminary results on an effort, currently in progress, to generate an exact solution of Einstein's equation, suitable for describing spacetime around a rotating compact object. Specifically, the form of the Ernst potential on the symmetry axis and its connection with the multipole moments is discussed thoroughly. The way to calculate the multipole moments of spacetime directly from the value of the Ernst potential on the symmetry axis is presented. Finally, a mixed ansatz is formed for the Ernst potential including parameters additional to the ones dictated by Sibgatullin. Thus, we believe that this talk can also serve as a comment on choosing the appropriate ansatz for the Ernst potential.
123174300
A Newtonian problem as an insightful tool for the behavior of gravitational-wave sources
We present the intriguing mathematical and physical similarities arising from the study of the Kerr metric and the Euler's problem of two fixed gravitational centers. We show how one could extend these similarities to physical problems that emerge from the above integrable problems, when both are slightly perturbed.