ACCELERATOR PHYSICS ISSUES AT THE POHANG LIGHT SOURCE

Since PLS started operation with 2 GeV beam in the range of 100 mA in 1994, the operation of PLS has aimed to realize stable beam operation with higher beam currents and higher beam energy. Through improvements in operational beam modes and cure of the beam instabilities, beam availability in the ring was raised to about 95% and beam quality could be also improved. We present several issues ofacceleratorphysicsthat haveperformedto achieve these improvements: such as operation beam modes, cure of beam instabilities, beam lifetimes, tune survey of dynamic aperture, estimation of the ring impedance, coupling constant and design of a low emittance lattice at the ring. OPERATIONAL BEAM MODE We have applied two methods to store the beams of 2.5 GeV: first method was to ramp the beam of 2 GeV in the ring to 2.5 GeV and second method was to perform full energy injection from the linac. We present these methods that have investigated for the 2.5 GeV beam operation.