The cyclotron chamber was designed around use in a 12-inch magnet, although initially tested in a 9-inch magnet. The chamber started out as a stainless steel bar that was about 3 inches by 1 inch by 42 inches. It was rolled, seem welded, and machined to specification by the Rutgers Machine Shop.

Fig.1 Tim holding the freshly rolled stainless steel bar.

Fig.2 The bar was rolled and seem welded prior to machining.

For achieving the best vacuum possible it was decided to use metal seals where ever possible. The machine shop TIG welded 1.33" and 2.75" conflat flange ports to the chamber with 1-inch ID stainless steel pipe. Use of the standard conflat style flanges made assembly and later modifications quite easy. Viton O-rings were used to make the vacuum tight seal between the chamber and the top and bottom lids. These seals have allowed the vacuum system to achieve pressures as low at 5E-7 Torr in the chamber.

Fig.3 Chamber with 1-inch port pipes TIG welded.

Fig.4 A quick check to see how things will fit.

Fig.5 Another view.

One quarter inch thick Aluminum was used for the lids, although not considered the best for vacuum applications. It was expected that modifications to the pole tips would eventually be desired, so it was essential that a material who was magnetically transparent be used for the lids - the stainless steel chamber already satisfied this requirement. The Al lids move slightly when vacuum is pulled, but this fact is only noticed in the RF system (see the 9-inch RF system discussion).

Fig.6 Picture of the chamber opened summer of 2003.

The chamber houses quite a bit, the ion source, electron catcher, the dee and the dummy dee, the fluorescent screen, and the target - now an ion collector. Mounted to the chamber are two pressure gauges, two linear positioners, an RF pickup, the dee stem and its ceramic break, two view ports, ion source gas and power lead feed-throughs, and the target holder. All ports are mounted using the metal sealed conflat flanges, with the exception of the target holder. The target holder is adapted to an O-ring based "Kwick-Flange" port since the target holder is removed frequently.

Fig.7 Top view of opened cyclotron chamber in August of 2004 (dummy dee removed for photo).

Fig.8 Labeled ports on RU 12-inch cyclotron chamber.