[en] Two techniques are discussed for allowing fast changes in energy or ion species at the 88 inches Cyclotron at LBL. Fast energy changes are implement by accelerating different charge states of a heavy ion or different isotopes with the same charge state. This technique requires keeping all magnetic fields constant and scaling all voltages proportional to the ion charge-to-mass ratio. With the high charge states produced by the new Advanced ECR (AECR) source, energies as high as 13 MeV/u were obtained with ^78and86Kr and 6-8 MeV/u with ^{112,116,120,and124}Sn. The availability of fast energy changes has made it possible to measure detailed excitation functions of nuclear reaction products with an efficient use of accelerator time. A related technique for fast switching of ions consists of running a cocktail of several species in the EC exclamation point R or AECR source, injecting all species of near resonant charge-to-mass ratio into the cyclotron, then extracting different ions by adjusting the resonant frequency a few kHz

[en] After a number of refinements, the stability and ease of tuning of the LBL AECR ion source are greatly improved. Several nuclear science experiments have now used cyclotron ion beams injected by the AECR ion source and have taken advantage of its good short and long term-stability and high performance. Refinements include installation of a dc filament power supply for the electron gun, improved gas flow control.and temperature stabilization of parts of the microwave transmission network. Measurements of the mean plasma potential and plasma potential difference were made on the AECR and the LBL ECR sources. The absolute. mean potentials of plasmas of oxygen, argon, and argon mixed with oxygen in the AECR have been determined. These plasma potentials are positive with respect to the plasma wall and are on the order of a few tens of volts for microwave power up to 600 W and normal operating gas flow. Electrons injected by an electron gun into the AECR plasma reduce the plasma potentials. Beam energy spreads of oxygen, argon and argon mixed with oxygen have also been measured. Measurement of the plasma potential difference between the first and the second stage of the LBL ECR ion source shows that the plasma potential in the first stage is higher than the second stage. Such plasma potential differences range from about 10 to 200 volts depending on the microwave power and density of neutral atoms. With these potential differences, typically of 10 to 40 V at the LBL ECR running conditions, most of the 1+ ions produced by the first stage are probably not be confined by the second state plasma. Thus it appears that the main function of a microwave-driven first stage is to provide electrons to the second stage plasma, as is done with an electron gun in the AECR source

[en] The AECR source, which operates at 14 GHz, is being developed for the 88-Inch Cyclotron at Lawrence Berkeley Laboratory. The AECR has been under source development since December 1989, when the mechanical construction was completed. The first AECR beams were injected into the cyclotron in June of 1990 and since then a variety of ion species from the AECR have been accelerated. The cyclotron recently accelerated ²⁰⁹Bi³⁸⁺ to 954 MeV. An electron gun, which injects 10 to 150 eV electrons into the plasma chamber of the AECR, has been developed to increase the production of high charge state ions. With the electron gun the AECR has produced at 10 kV extraction voltage 131 eμA of O⁷⁺, 13 eμA of O⁸⁺, 17 eμA of Ar¹⁴⁺, 2.2 eμA of Kr²⁵⁺, 1 eμA of Xe³¹⁺, and 0.2 eμA of Bi³⁸⁺. The AECR was also tested as a single stage source with a coating of SiO₂ on the plasma chamber walls. This significantly improved its performance compared to no coating, but direct injection of electrons with the electron gun produced the best results. 5 refs., 6 figs., 4 tabs

[en] The new Advanced ECR (AECR) source is being developed for the 88-Inch Cyclotron at Lawrence Berkeley Laboratory. It operates at 14.5 GHz, compared to 6.4 GHz for the present LBL ECR source. An electron gun injects electrons into the plasma chamber to increase the production of high charge state ions. The first AECR beams were injected into the cyclotron in June of 1990 and since then a variety of ion species from the AECR have been accelerated, including beams from oxygen at 32 MeV/u to bismuth at 4.6 MeV/u. A Xe³²⁺ beam of 1054 MeV or 8 MeV/u was accelerated. 4 refs., 3 figs., 2 tabs

[en] This report describes the activities of the Nuclear Science Division (NSD) for the two-year period, January 1, 1995 to January 1, 1997. This was a time of major accomplishments for all research programs in the Division-many of which are highlighted in the reports of this document

[en] A new injection line for two ECR sources is under construction at SARA. The beam delivered by MINIMAFIOS or FERROMAFIOS has to be transported down to the inflector at the center of the injector cyclotron over a distance of 18 meters. The line includes a 11 m long electrostatic channel. Beam optics calculations and first results of emittance measurements of FERROMAFIOS are presented

[en] Starting with the pioneering work of R. Geller and his group in Grenoble (France), at least 14 E.C.R. sources have been built and tested during the last five years. Most of those sources have been extremely successful, providing intense, stable and reliable beams of highly charged ions for cyclotron injection or atomic physics research. However, some of the operational features of those sources disagreed with commonly accepted theories on E.C.R. source operation. To explain the observed behavior of actual sources, it was found necessary to refine some of the crude ideas about E.C.R. sources. Some of those new propositions are explained, and used to make some extrapolations on the possible future developments in E.C.R. sources

[en] In this report, the design and present performance of the RT-ECR will be presented. In addition, two new sources are under development at NSCL, and brief reports will be made here on each of these. A compact single stage source for light ions and metals, CP-ECR, is now under construction. The second, a superconducting source having a magnet capable of ECR operation a high as 30GHz, the SC-ECR project, is now in the design phase. (author)

[en] Intensive work on superconducting cyclotrons began at MSU in late 1973 (a brief earlier study had occurred in the early 1960's) and continues vigorously at present. One large cyclotron, the ''K500'', has been operating for a number of years, a second, the ''K800'', is nearing completion, the first operating tests of its magnet having occurred at the time of the previous conference, and a third, the ''medical cyclotron'', is now also nearing completion with first operation of its magnet expected just after the present conference. These cyclotrons like other superconducting cyclotrons are all dramatically smaller than comparable room temperature machines; overall weight is typically about 1/20th of that of room temperature cyclotrons of the same energy. This large reduction in the quantities of materials is partially offset by added complexity, but finally, a net overall cost savings of 50 to 70 % typically results; as a consequence the superconducting cyclotron is widely viewed as the cyclotron of the future. The thirteen years of experience at MSU involving three of these cyclotrons, together with much important work at other laboratories, gives a rather clear view of the advantages and disadvantages of various design approaches including by now a rather significant period of long term evaluation. This paper reviews highlights of this program. (author)

[en] SARA (Systeme Accelerateur Rhones-Alpes) was presented at the last Conference on Cyclotrons at CAEN. It is a two cyclotron accelerator; the first one is a compact cyclotron (K=88) which has been running since 1967, the second accelerator (K=160) has four separated sectors. Its construction began in 1977, the first beam was accelerated in March 1982 at the nominal energy of 30 MeV/amu and the first physics experiment was completed in May 1982. SARA has been routinely operated since September 1983 with the ECR MICROMAFIOS