Progress in the Next Linear Collider Design

An electron/positron linear collider with a center-of-mass energy between 0.5 and 1 TeV would be an important complement to the physics program of the LHC in the next decade. The Next Linear Collider (NLC) is being designed by a US collaboration (FNAL, LBNL, LLNL, and SLAC) which is working closely with the Japanese collaboration that is designing the Japanese Linear Collider (JLC). The NLC main linacs are based on normal conducting 11 GHz rf. This paper will discuss the technical difficulties encountered as well as the many changes that have been made to the NLC design over the last year. These changes include improvements to the X-band rf system as well as modifications to the injector and the beam delivery system. They are based on new conceptual solutions as well as results from the R&D programs which have exceeded initial specifications. The net effect has been to reduce the length of the collider from about 32 km to 25 km and to reduce the number of klystrons and modulators by a factor of two. Together these lead to significant cost savings

A Discussion of the NLC Linac Alignment and Tuning Procedures

In this paper, we give a short introduction to the NLC linac alignment and tuning procedures. A more detailed description of the techniques, as well as the simulations verifying the techniques, can be found in the NLC Zeroth Order Design Report. In the next sections, we will describe the basic layout of the linac, the pre-alignment strategy, and the beam-based alignment techniques. Then, we will discuss the stability issues and possible methods of additional emittance control. Finally, it should be noted that the linac model described in this note is probably incorrect with the new (May 1997) parameters where the accelerator structures are naturally grouped in set of three and not pairs. However, the correction procedures described are still those thought to be utilized

NLC Luminosity as a Function of Beam Parameters

Realistic calculation of NLC luminosity has been performed using particle tracking in DIMAD and beam-beam simulations in GUINEA-PIG code for various values of beam emittance, energy and beta functions at the Interaction Point (IP). Results of the simulations are compared with analytic luminosity calculations. The optimum range of IP beta functions for high luminosity was identified.Comment: 4 pages, 7 figure

Simulation Studies of the NLC with Improved Ground Motion Models

The performance of various systems of the Next Linear Collider (NLC) have been studied in terms of ground motion using recently developed models. In particular, the performance of the beam delivery system is discussed. Plans to evaluate the operation of the main linac beam-based alignment and feedback systems are also outlined.Comment: Submitted to XX International Linac Conferenc