Development of an H− ion source for the high intensity proton linac

Oguri, H.; Okumura, Y.; Hasegawa, K.; Namekawa, Y.; Shimooka, T.

doi:10.1063/1.1428418

Cited by 18 publications

(8 citation statements)

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“…So far the production of H − with lower temperature by using Cs is not consistently demonstrated, although there are very good source data of a cesiated source. 19 but there is also an experience that only the emittance= f͑H − ͒ is extended. 18 Generally for the lowest emittances under cesiation, charge exchange reactions were assumed.…”

Section: H − Current and Emittancementioning

confidence: 97%

New developments in multicusp H− ion sources for high energy accelerators (invited)

Peters

2008

Review of Scientific Instruments

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A functional description of multicusp H(-) sources is given, focusing on the fundamental elements of this source type: the discharge chamber, the extraction plasma region, and electron dumping. Design choices for these elements will be presented and compared. The options of rf and filament heating of the discharge chamber will be presented. Also, the construction opportunities in the extraction plasma region using filter field arrangements and collars are described. Three methods to dump the electrons at three different regions are discussed. In a brief history, the development of multicusp sources are described. The status of the new sources under development at DESY, SNS, and in Japan will be given in a table for all types of operational H(-) sources. Finally, the limits to the H(-) current and emittance as well as the Cs question will be discussed.

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Section: H − Current and Emittancementioning

confidence: 97%

New developments in multicusp H− ion sources for high energy accelerators (invited)

Peters

2008

Review of Scientific Instruments

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“…17 The advantage of such an approach lies in the fact that the parasitic electrons are at first being extracted in a geometry with cylindrical symmetry, avoiding the build-up of asymmetric space-charge forces that could act on the very slow ions near the meniscus. When the electrons are finally being separated from the ion beam their own speed is high enough that asymmetric space-charge forces become essentially negligible.…”

Section: Discussionmentioning

confidence: 99%

Design, Operational Experiences and Beam Results Obtained with the SNS H− Ion Source and LEBT at Berkeley Lab

Keller¹,

Thomae²,

Stöckli³

et al. 2002

AIP Conference Proceedings

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Abstract:The ion source and Low-Energy Transport (LEBT) system that will provide H -ion beams to the Spallation Neutron Source (SNS)** Front End and the accelerator chain have been developed into a mature unit that fully satisfies the operational requirements through the commissioning and early operating phases of SNS. Compared to the early R&D version, many features of the ion source have been improved, and reliable operation at 6% duty factor has been achieved producing beam currents in the 35-mA range and above. LEBT operation proved that the purely electrostatic focusing principle is well suited to inject the ion beam into the RFQ accelerator, including the steering and pre-chopping functions. This paper will discuss the latest design features of the ion source and LEBT, give performance data for the integrated system, and report on commissioning results obtained with the SNS RFQ and Medium-Energy Beam Transport (MEBT) system. Prospects for further improvements will be outlined in concluding remarks. INTRODUCTIONBerkeley Lab has just completed building the linac injector (Front End, FE) for the Spallation Neutron Source project (SNS), and the commissioning of the entire system is proceeding. The main subsystems are the H -ion-source, the low-energy beam-transport system (LEBT), the 2.5-MeV radio-frequency quadrupole (RFQ) accelerator, and the medium-energy beam-transport system (MEBT). Ion source and LEBT are the subject of this paper; their task is to create a 65-keV, 38-mA ion beam, to match and steer it into the RFQ, and to pre-chop it into mini-pulses of about 600 ns duration. The nominal duty factor is 6%, with 1-ms macro-pulse length and 60-Hz repetition rate.Based upon the main design features of the SSC ion source, 1 an R&D version of the SNS ion source was built first to demonstrate the viability of the chosen approach, utilizing an rf driven discharge inside a multicusp plasma generator with magnetic filter, cesium enhancement, and electron suppression at low energy.2 This source version did not allow implementing cesium enhancement and electron suppression at the same time, but both features were proven to work satisfactorily in separate tests.

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“…18 The advantage of such an approach lies in the fact that the parasitic electrons are at first being extracted in a geometry with cylindrical symmetry, avoiding the build-up of asymmetric space-charge forces that could act on the very slow ions near the meniscus. When the electrons are finally being separated from the ion beam their own speed is high enough that asymmetric space-charge forces become essentially negligible.…”

Section: Discussionmentioning

confidence: 99%