Design of the SSC linac
The preliminary design of the 600-MeV H/sup -/ linac for the Superconducting Super Collider (SSC) injector is described. The linac must provide a 25-mA beam during 7-35 mu s macropulses at 10 Hz within injection bursts. Normalized transverse emittances of less than 0.4 pi mm-mrad (RMS) are required for injection into the low Energy Booster (LEB) synchrotron. Cost, ease of commissioning, and operational reliability are important considerations. The linac will consist of an H/sup -/ source with electrostatic low-energy beam transport (LEBT), a 2.5-MeV radiofrequency quadrupole (RFQ) accelerator, a 70-MeV drift-tube linac (DTL), and 530 MeV of coupled-cavity linac (CCL). The RFQ and DTL operate at 428 MHz and the CCL operates at 1284 MHz. A modest total length of 143 m results from the tradeoff between cost optimization and reliability.<<ETX>>
The SSC Linac: Status of Design and Procurement Activities
The Linear Accelerator1,2 (Linac) is the first element in the injector chain for the Superconducting Super Collider (SSC). It must be operational by October 1995 in order to commission the Low Energy Booster (LEB). The physics design of the Linac is now essentially complete, detailed engineering is well advanced, and manufacturing has begun. This paper will review the physics design with emphasis on recent significant improvements, summarize mechanical design and construction status, and describe recent achievements in the development program.
Study on Transmission Characteristics of Vertical Rail Vibrations in Ballast Track
A plane half-track model and a periodic track-substructure model are established. The spectral element method and spectral transfer matrix method are developed and applied to investigate the track decay rate (TDR) and transmission rate (TR) of the vertical rail vibrations, which can reflect the transmission characteristics in the longitudinal and downward directions, respectively. Furthermore, the effects of different track parameters on TDR and TR are investigated. The results show that the antiresonance frequency of the rail and the out-of-phase resonance frequency of the rail and sleeper form the boundary frequencies of the high-attenuation zone for longwise vibration transmission, where the vibration absorption of the sleeper is significant. The downward transmissibility of vertical rail vibrations is greatest around the antiresonance frequency of the rail. Vertical rail vibrations are primarily transmitted in the downward direction at low frequencies, while they are mainly transmitted along the rail at high frequencies. Stiffer rail pads can make more vibrations transmitted downwards to the sleeper above the antiresonance frequency of the rail, while the changes of other track parameters have different effects on the transmission characteristics. Additionally, a field measurement is performed for verification, and the simulations are well consistent with measurements.