Tandem Specifications
The ESTU (Extended Stretched TransUranium) tandem accelerator at the A.W. Wright Nuclear Structure Laboratory, Yale University is one of the largest operating electrostatic accelerators world-wide. Designed to incorporate components from the original MP tandem, which operated from 1966 to 1985, the ESTU employs the proven HVEC column and tube designs with an NEC Pelletron charging system and a Vivirad intershield.
The accelerator consists of a column made up of five 8 foot long high voltage modules on each side of a large center terminal, insulated with SF6 and contained in a tank 98 feet long and 25 feet in diameter. This structure sustained a D.C. potential of 22.5 MV during commissioning tests, corresponding to the design voltage of 4.5 MV per section. All of the ten accelerator tubes will individually sustain this potential. Beams can be accelerated at terminal potentials of at least 21 MV.
A high resolution negative ion injector, mounted on a pre-acceleration platform operating up to 200 keV, can inject beams of all masses from 1 to 250 with a mass resolution of better than 1/200 and intensities up to 20 microamps.
The accelerated beam is analyzed and switched by convential magnetic elements in the accelerator vault, whence it can be directed into any one of seven beam lines in target room 1. Two of these lines extend into target room 2, one passing through a second switcher magnet with the capability of feeding a further six beam lines.
The ETSU was installed between 1985 and 1987 and began operation in 1988. The beam is currently available for experiments for about 4500 hours per year.
