Magnet system for an ECR ion source

Abstract

A b s W t -A superconducting magnet usssmbly Bar Been built for rm ECR (Electron Cyclotron Resonarm$ Ion sowce at the 88~inch cyclohoti at LBL'. Three 34-cm ID solenoids provide axhl plasma cotijintw" and U sexfupole ussembly in the solenoid bore provides radial stabill@. Two large solenoid8 are spaced SO em. npwi with a smaller opposing solenoid bedween. The sexlupole ussembly is 92 cm long with winding inner diameter of 20 cm. and outer diameter of 27.2 em. Tfis design goat is fo achieve afield on axis of 4 T und 3 T a t the mirrors with 0.4 T behvees and a sexfapole field of 2.0 T at IS-cm diumeter iti the confinement volume. Emfr solenoid uses rectrsngrrlar conductor wtth mpper/'SC ratio of 4; flie three coils are wet-wound on a one-piece aluminlrm bobbin with aluminum bnndti!g for rudiui suppord. The sexapole uses rectangular conductor with copper/SC ratio of 3. EacR of the 6 eoik is wet-wound with filled epoxy ori a metal pole; the ends of the pole are ahminum and the central 34-cm h lron to augment the sextupokfldd. The a& coils me assembled on a 2O-cni4lD stainless steel hrbe with a I.4-cm thick 30.0.cm OD aluminum tribe over the assembly for striictural support. Thin metal bludders are exparrded adtnut!ially behveen each coil axially ab the ends to pre-load the assembly, The sexhrpob assembbflts inside lire solenoid bobtin, wlikb provMes support for the magnetic forces. The magnet exceeds design requirements with ni inim um training.

Construction and component testing of TAMU3, a 14 Tesla stress-managed Nb3Sn model dipole

“…To achieve accurate and uniform isostatic preload and force containment on the complete coil package, Wood's metal filled stainless steel bladders will be employed similar to TAMU2 and other magnets [9]. Vertical bladder preload friction locks the Ti end hoop piers in place when cold (4.2 K) to minimize axial movements.…”

Fabrication of ‘TAMU3’, a ‘Wind/React’ stress-managed 14T Nb3Sn block coil design

“…The use of metal filled bladders was first employed by Clyde Taylor (LBNL) in order to properly support an ion source sextupole [8]. The large cylindrical bladders between the Al Stress-Cylinder The only modifications to this apparatus were more temperature controllers and independent heating units for the valves next to the bladder stubs.…”

The effect of low temperature cryocoolers on the development of low temperature superconducting magnets

“…The Lawrence Berkeley Laboratory is active pursuing the use of cryocoolers for superconducting magnets for the following applications: 1) the three superconducting dipoles in the ALS ring will be cooled using 1.5 W cryocoolers [6]; 2) a mixed superconducting sextupole and solenoid for an ion source for the 88 inch cyclotron will be cooled using a pair of 1.5 W coolers [7]; 3) cryocoolers will probably be used to cool test magnets for the neutrino factory; 4) a test multi-bore quadrupole for heavy ion fusion can be cooled using cryocoolers; 5) a proposed superconducting undulator magnet for the ALS light source can be cooled using a 4.2 K cryocooler (probably a low vibration pulse tube cooler); and 6) a proposed superconducting gradient magnet for measuring the thickness and moisture content of paper being processed in a paper mill can be cooled using a 4.2 K cryocooler. The paper mill application is an application where conventional superconducting magnet cooling systems are completely unacceptable to the industry.…”