ANU Heavy Ion Accelerator Facility: The 14UD pelletron скачать в хорошем качестве

ANU Heavy Ion Accelerator Facility: The 14UD pelletron

The Department of Nuclear Physics houses two accelerators which operate as a National Facility, with the accelerator laboratories making up part of the Australian Collaboration for Accelerator Science (ACAS). The 14UD Pelletron electrostatic accelerator and the superconducting linear accelerator produce charged atoms (ions) with up to 10% of the speed of light. This is enough to overcome the electrostatic repulsion between atomic nuclei, and initiate nuclear reactions. The 14UD accelerator, housed in a 40m tall tower, can operate at over 15 million Volts, and delivers ion beams with pulse widths from a nanosecond to seconds. Beam energies can be doubled by a superconducting linear post-accelerator (LINAC). The varied interactions of beam nuclei with target nuclei are studied using state-of-the-art detector arrays, developed in-house, and located at the ends of the 10 beam lines. Our nuclear structure research investigates the properties of, and interactions between individual excited states of metastable nuclei, whilst the complex interactions between colliding nuclei are the subject of nuclear reaction dynamics studies. In our applied research, the accelerated beams are used in AMS measurements and in advanced materials characterization, to investigate subjects as diverse as landform evolution and internal electric fields in semiconductors. These main areas of research are complementary, overlapping in terms of shared techniques, and the understanding achieved of interrelated aspects of nuclear behaviour. Further information about the facility can be found at The 14UD, in stand-alone operation since 1973, services seven well established beamlines plus three new ones in the LINAC Hall. It runs between 3500 and 5000 hour per year depending on competition from development projects and is operated by experimenters. Ion sources include a NEC Multi-Sample SNICS and a Gas Cathode equipped SNICS II. These feed a high resolution injector system and a comprehensive pulsing system. The pulser boasts a programmable chopper which produces intervals of beam as short as 50 ps with repetition rates from sub microseconds to multi-milliseconds. A double gridded buncher, operating at 9.375 MHz, plus two harmonics, compresses the beam into pulses less than 1 ns wide at injection into the 14UD. Two orthogonal post acceleration choppers clean up the pulses. The phase detector is in front of the image slits of the energy analysing magnet. The high voltage terminal of the 14UD includes a gas stripper differentially pumped by two turbopumps and two ion pumps. This is followed by the existing foil stripper and electrostatic triplet quadrupole lens. All terminal equipment is controlled via optical cable. The 14UD routinely operates above 15.5 MV. The voltage performance upgrades include the installation of NEC compressed geometry accelerator tube, which increases the insulated length by 12%, and the local development of a robust resistor grading system for the column and tube.