摘要:

A new injector for the superconducting linac ALPI is under construction at LNL. This linac (called PIAVE) will be able to accelerate ions up to uranium, for an equivalent voltage of about 8 MV, and will improve the performances of ALPI (presently injected by a 15 MV Tandem) both in intensity and ions species availability. We shall discuss the design choices adopted for PIAVE, with the use of two compact 80 MHz superconducting RFQ up to about 530 keV/u, followed by eight independently phased QWR (minor modification of those already installed in ALPI). This approach, made possible by a rather sophisticated beam dynamics design, allowed to concentrate the R&D effort on the development of the RFQ structure. Details like the optimization of the acceleration in the RFQ, the bunching system and the transition between the two RFQs will be discussed. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58945

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Four new super-conducting Quarter Wave Resonators (QWR,&bgr;=0.13), obtained by niobium sputtered on an OFHC copper substrate, were recently installed and tested on the ALPI post-accelerator (1). The resonators substituted four similar ones that were operating at 4 MV/m at 7 W, because two of their couplers jammed. Now the cavities have a new coupler design and show an acceleration field, measured with different ion species, in excess of 6 MV/m at 7 W (about 1 MeV energy gain per cavity per charge unit). The resonators show excellent stability on long time runs even at such a high accelerating field. The high accelerating fields, together with the good stability and the low costs, made this technology almost ideal for heavy ion acceleration. Moreover the niobium sputtering process was applied to substitute the electroplated lead coating in four medium&bgr;(&bgr;=0.11)resonators after only minor changes in the resonator shape. Accelerating fields in excess of 4.5 MV/m a 7 W could be obtained in laboratory even though the cavity geometry was not optimised for the sputtering procedure. Beam tests are foreseen soon. The replacement of the installed resonators with sputtered units can either improve the ALPI performance or reduce the cryogenic power consumption. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58946

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

This paper reports the status and details of the costs of construction of niobium superconducting resonant cavities for a linear accelerator, presently being built as a booster for the 15 UD tandem Pelletron accelerator at the Nuclear Science Centre, New Delhi. The linear accelerator will have three cryostal modules, each holding eight quarter-wave resonators. Construction of a batch of ten resonators for the linac started at Argonne National Laboratory in May 1997. For production, all fabrication and all electron beam welding is being done through commercial vendors. Details of construction and present status of the project are presented. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58984

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

Quarter wave resonators used in independently phased linacs have a wide incident velocity acceptance above the velocity of about0.5&hthinsp;&bgr;opt,where&bgr;optis the optimum incident velocity for the resonators. Their transit time factor (TTF) crosses zero at the velocity of0.5&hthinsp;&bgr;optand has a small negative peak at0.35&hthinsp;&bgr;opt.An acceleration of ions across the zero-crossing velocity starting from a velocity in the negative peak is discussed. For taking into account of velocity changes in the resonators, a numerical calculation was carried out and it was found that a very slow acceleration can occur if the rf phase is properly changed over the transitional region. In the calculation,Cl10+ions and the shape of the quarter wave resonators of&bgr;opt=0.1in the JAERI Tandem Superconducting Booster were chosen. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58985

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

A system of computers connected by a local area network(ARCNET®)controls the Munich accelerator facility. This includes ion sources, the tandem accelerator, the beam transport system, the gas handling plant, parts of experimental setup and also an ion source test bench. ARCNET is a deterministic multi-master network with arbitrary topology, using coax cables and optical fibers. Crates with single board computers and I/O-boards (analog, parallel or serial digital), dependent on the devices being controlled, are distributed all over the building. Personal computers serve as user interfaces. The LAN communication protocol is a client/server protocol. Communication language and programming language for the single board computers is Forth. The user mode drivers in the personal computers are also written in Forth. The tools for the operators are MS-Windows applications, programmed in Forth, C++ or Visual Basic. Links to MS-Office applications are available, too. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58986

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

In the fall of 1992 at the SNEAP (Symposium of North Eastern Accelerator Personnel) a project to upgrade the ATLAS (Argonne Tandem Linear Accelerator System) control system was first reported (1). Not unlike the accelerator it services the control system will continue to evolve. However, the first of this year has marked the completion of this most recent upgrade project. Since the control system upgrade took place during a period when ATLAS was operating at a record number of hours, special techniques were necessary to enable the development of the new control system “on line” while still serving the needs of normal operations. This paper reviews the techniques used for upgrading the ATLAS control system while the system was in use. In addition a summary of the upgrade project and final configuration, as well as some of the features of the new control system is provided. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58947

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

This paper reviews the progress made in the development of the linac booster for Nuclear Science Centre (NSC). The prototype resonator for the booster has surpassed design accelerating field. A cryostat has been fabricated to house this prototype for in beam tests. The cryogenic system has been installed and several rf modules have been constructed. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58987

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

A single-gap multi-harmonic buncher, developed in collaboration with Argonne National Laboratory, has been installed in the pre-acceleration region of NSC Pelletron. This buncher is required for injecting bunched beam into the booster LINAC, presently under construction. A saw-tooth voltage generated across a single gap formed by a closely spaced pair of grids is used for bunching the dc ion beam produced by the Pelletron accelerator. This saw-tooth voltage is produced by adding a sinewave with its three higher harmonics in proper phase and amplitude.28Sibeam has been bunched successfully using this buncher. The best FWHM of the bunched beam was 1.5ns and the maximum efficiency of bunching was 50&percent;. The bunching voltage had no steering effect on the beam. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58948

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

A new time-of-arrival (TOA) control system has been developed at the Argonne Tandem Linear Accelerator System (ATLAS) for very low intensity radioactive ion beams. This new system utilizes a plastic scintillator which intercepts a small fraction of the beam edge particles and measures the time-of-arrival of a bunched beam at the entrance to the ATLAS superconducting linac after acceleration through the ATLAS 9MV tandem injector A radioactive56Nibeam has been accelerated through a 9MV tandem and then injected into a superconducting linear accelerator for further acceleration. The detector has been successful at stabilizing the pre-tandem bunching system with beam currents as low as2×104particles per second. This paper will describe the electronic circuitry developed for this system and details about the control range and limits. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58949

出版商:AIP    

年代:1999

数据来源: AIP

摘要:

ECR plasmas are utilized for : 1) Charge breeding of 1+ RIB into N+ RIB in continuous regime with an efficiency for one given charge of 10&percent; for noble gases and about 5&percent; for solid elements. 2) Charge breeding with beam bunching (bunch duration 20 ms, 5 Hz) was obtained forRb15+ions with an efficiency of 2.2&percent;. These results are very reproducible and need only about 200 W of RF power. The number of ions contained in one bunch exceeds 1000 times those achieved with EBIS systems. The ECR trap is better suited for pulsed post acceleration. 3) Ion accumulation in the ECR plasma trap may become a method for realizing a radioactive target. ©1999 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.58988

出版商:AIP    

年代:1999

数据来源: AIP