M. C. ROSS, R. IVERSON, K. JOBE, D. MCCORMICK, P. TENENBAUM, P. RAIMONDI (SLAC)
The Next Linear Collider (NLC) electron and positron beams are capable of damaging the linac accelerating structure and beamline vacuum chambers during an individual aberrant accelerator pulse. Machine protection system (MPS) considerations have an impact on the engineering and design of most machine components downstream of the damping ring injector complex. Beam tests have been done at the SLAC FFTB to examine the behavior of the copper at and above the damage stress threshold. In this paper we present results of damage studies in copper as the predicted pulse heating is varied from below melting to near vaporization. The goal of the tests was to determine allowable limits on beam size and intensity of a benign single bunch pilot beam to be used in testing linac systems. Typical expected pilot beam parameters (compared with nominal) are: 10 times reduced intensity, 10 times increased horizontal emittance and 1000 times increased vertical emittance, resulting in a reduction in charge density of 105. The tests we report here used short 1 mm beam pulses of between 3 and 20 x 10^9 electrons with transverse sizes between 45 micron^2 and 200 micron^2
* Work supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00515
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