High current density negative ion source for beam line transport studies

Abstract

The Fermilab Electron Cooling Program requires a 20-m solenoidal region to interact 8-GeV antiprotons with an escorting beam of 4.3-MeV electrons to improve the phase-space quality of the antiproton beam. The solenoidal section with additional transport lines to take and return a 0.5-A electron beam from an electrostatic accelerator, for energy recovery, must be precisely aligned and adjusted. For the initial setup and study, and later testing of this line, a 12.4-keV H -beam can be used to simulate the 4.3 MeV electron beam. For this purpose a high-brightness H -ion source has been developed and tested. The source, a semiplanatron type, with a hollow cathode discharge and spherical cathode focusing of the emitted ions to the emission aperture has given an emission current density up to 0.7 A/cm 2 . Continuous operation of 4 weeks has been demonstrated. Such an optimized source could have many applications for tandem accelerators, ion beam lithography and ion implantation.

Measurement of small radius gradient magnets using ion beams

“…Graph 2 shows the difference between the desired and measured field errors. A sextupole is evident and corresponds to a second order coefficient of 1.3 G/in 2 …”