Results of beam tests on a high current EBIS test stand
At Brookhaven National Laboratory there is an R&D program to design an Electron Beam Ion Source (EBIS) for use in a compact ion injector to be developed for the Relativistic Heavy Ion Collider (RHIC). The BNL effort is directed at developing an EBIS with intensities of 3/spl times/10/sup 9/ particles/pulse of ions such as Au/sup 35+/ and U/sup 45+/, and requires an electron beam on the order of 10 A. The construction of a test stand (EBTS) with the full electron beam power and 1/3 the length of the EBIS for RHIC is nearing completion. Initial commissioning of the EBTS was made with pulsed electron beams of duration <1 ms and current up to 13 A. Details of the EBTS construction, results of the pulse tests, and preparations for DC electron beam tests are presented.
DESIGN AND INITIAL RESULTS OF A HIGH CURRENT EBIS TEST STAND
There is a program at Brookhaven National Laboratory to do the R&D required to design an Electron Beam Ion Source (EBIS) which could be used as part of a new, compact heavy ion injector for RHIC. This injector could serve as a replacement for the tandem, offering a wider range of ion species, more efficient operation (single-turn injection into the Booster), and lower operating costs. The program addresses issues relevant to the scaling of EBIS performance to RHIC requirements. The BNL effort is directed at reaching intensities of 3x10 9 particles/pulse of ions such as Au 35+ and U, and requires an electron beam on the order of 10A. On our existing EBIS, pulsed electron beams above 1A and ions such as Tl have been produced. Much of our future research will move to a new test stand, now under construction. While the primary function of this test stand is the study of a 10A electron beam, it will be used to develop the technologies and study the physics relevant for a high intensity EBIS. The design and status of this EBIS, including the 10A electron gun and 1m long, 5T, warm bore superconducting solenoid, is described.
Time behavior of gas pressure and PD activity in insulation cavities under AC voltage
In the framework of developing defect-based life models (i.e. the life model of partial discharge-induced damage growth from a micro-void in polymer matrix), ageing tests were performed on PE layered specimens with artificial cavities under constant gas pressure and constant gas volume conditions, respectively. Time behavior of the discharge repetition rate and amplitude were recorded and compared under these two conditions. Results show that pressure variation has little influence on PD activities at constant gas volume. Under constant gas pressure, the evolution of gas volume has similar characteristic to the product of discharge amplitude and repetition rate.