We investigate high brightness pumping of a multi-kW Yb fiber amplifier in a bi-directional pumping configuration. Each pump outputs 2 kW in a 200 μm, 0.2 NA multi-mode fiber. Gold-coated specialty gain fibers, with 17 m MFD and 5-dB/meter pump absorption, have been developed. The maximum fiber amplifier output power is 3.1 kW, limited by multi-mode instability, with 90% O-O efficiency 12 GHz ...

A compact 10 kW RF power amplifier at 352 MHz was developed at FREIA for the European Spallation Source, ESS. The specifications of ESS for the conception of amplifiers are related to its pulsed operation: 3.5 ms pulse length and a duty cycle of 5%. The realized amplifier is composed of eight kilowatt level modules, combined using a planar Gysel 8-way combiner. The combiner has a low insertion ...

The ISAC RF system at present consists of a Radio Frequency Quadrupole accelerator, five Drift Tube Linear Accelerators, six bunchers, two choppers and a bunch rotator. The RFQ operates at the fundamental frequency of 35.36 MHz, while the DTLs operate at the third harmonic frequency of 106.08 MHz. The operating power ranges from 45 W to 120 W for the choppers, 1 kW to 20 kW for the DTLs and bun...

In the early seventies the notion that computers could be programmed to create images worthy of being called "realistic" was a dream brought closer to reality by diligent experimentation with models and with light and display algorithms. Within a decade great progress was demonstrated by the almost commonplace production of high-quality images. But while the most complex real or fantastical obj...

2.2 Heating and cooling systems The power of the global heating/cooling system has been voluntarily oversize in order to generate an artificial climate whatever the season in the large room. The mains components are: a reversible air-to-water heat pump: 40 kW a second heat pump (only chilled water) : 24 kW an electric coil (24 kW) two regulated fans (supplied & exhausted air) : 0-6000 m3/h a ru...

For any finite word w on a finite alphabet, we consider the basic parameters Rw and Kw of w defined as follows: Rw is the minimal natural number for which w has no right special factor of length Rw and Kw is the minimal natural number for which w has no repeated suffix of length Kw. In this paper we study the distributions of these parameters, here called characteristic parameters, among the wo...

The development of a 10-kW average power, 94-GHz gyroklystron amplifier is described. This average power was obtained with 11% radio frequency (RF) duty factor and 92-kW peak power in the TE01 circular cavity mode. The instantaneous bandwidth was 420 MHz, and the efficiency was 33.5%. Low-duty-factor testing also yielded a peak power of as much as 115 kW with 600-MHz instantaneous bandwidth. Th...