Understanding extraction and beam transport in the ISIS H− Penning surface plasma ion source

Lee

et al. 2010

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A front end is currently under construction consisting of a H(-) Penning ion source (65 keV, 60 mA), low energy beam transport (LEBT), and radio frequency quadrupole (3 MeV output energy) with a medium energy beam transport suitable for high power proton applications. Diagnostics can be divided either in destructive techniques such as beam profile monitor, pepperpot, slit-slit emittance scanner (preferably used during commissioning) or nondestructive, permanently installed devices such as photodetachment-based techniques. Another way to determine beam distributions is a scintillator with charge-coupled device camera. First experiments have been performed to control the beam injection into the LEBT. The influence of beam parameters such as particle energy and space-charge compensation on the two-dimensional distribution and profiles will be presented.

Section: Experimental Setup and Achieved Resultsmentioning

confidence: 99%

Diagnostic experiments at a 3 MeV test stand at Rutherford Appleton Laboratory (United Kingdom)

Gabor

Lee

et al. 2010

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“…For the studies presented here, the gap was either 13 or 6 mm, while the PA is technically not part of the LEBT both beamline components have to be treated together to achieve an optimized LEBT output (for further information see Ref. 1).…”

Section: Methodsmentioning

confidence: 99%

H– beam transport experiments in a solenoid low energy beam transport

Gabor

Back

et al. 2012

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The Front End Test Stand (FETS) is located at Rutherford Appleton Laboratory and aims for a high current, fast chopped 3 MeV H(-) ion beam suitable for future high power proton accelerators like ISIS upgrade. The main components of the front end are the Penning ion source, a low energy beam transport line, an radio-frequency quadrupole (RFQ) and a medium energy beam transport (MEBT) providing also a chopper section and rebuncher. FETS is in the stage of commissioning its low energy beam transport (LEBT) line consisting of three solenoids. The LEBT has to transport an H(-) high current beam (up to 60 mA) at 65 keV. This is the injection energy of the beam into the RFQ. The main diagnostics are slit-slit emittance scanners for each transversal plane. For optimizing the matching to the RFQ, experiments have been performed with a variety of solenoid settings to better understand the actual beam transport. Occasionally, source parameters such as extractor slit width and beam energy were varied as well. The paper also discusses simulations based on these measurements.

“…Additionally, the sector magnet is a combined function dipole, used to form the beam into a more uniformly round shape. 4 The performance of the ion source has been improved significantly in recent times, 5 meaning 55 mA of beam should now reach the LEBT on FETS. However, high beam current is not the only important factor.…”

Section: B Design Featuresmentioning

confidence: 99%

Plasma meniscus and extraction electrode studies of the ISIS H− ion source

Lawrie

Letchford

et al. 2010

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In order to reduce the emittance and increase the transported beam current from the ISIS Penning-type H(-) ion source, improvements to the extraction system are required. This ion source is currently being commissioned on the front end test stand at the Rutherford Appleton Laboratory, which demands higher extraction energies, higher beam currents, and smaller emittances. To facilitate this, the present geometry requires optimization. This paper details the experimental and simulation studies performed of the plasma meniscus and the possible electrode geometry modifications needed to extract the highest quality beam.