Aim of study:● recognition of long time phase fluctuation on the klystron output (especially during the period that beam arrives)●phase stability correlation with different system parameters change: HV drift, Gun iris temperature, GUN Cell 1 temperature.

Phase changes measurement in GUN HPC

Wojciech CICHALEWSKIwojciech.cichalewski@desy.de

28 February 2008

CHALLENGES ● ambiguous timing for: RF pulse start, Beam, Forward power readout, Controller output, HPC ADC (hard to synchronize measured signals !),● second preamplifier output has to be checked (suspicious signal shape and ADC saturation)● problems with klystron HV readout (ADC saturation?)

● not precise klystron output power measurement (probably ADC adjustment should be improved)

MEASUREMENT RESULTS: pulse-to-pulse studyTest time – 1h (measured each 2s). filename – amp_phase_k3_20080227_1656.matsample time – 700 us

Time domain RF gate phase measurement -1h test

Time domain klystron phase measurement - 1h test

MEASUREMENT RESULTS: pulse-to-pulse studyTest time – 3h (measured each 2s). sample time – 700 us