| Paper | Title | Page |
|---|---|---|
| MOPPD037 | Investigation of Space Charge Compensation at FETS | 445 |
|
||
| In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The ion source and LEBT are operational with the RFQ under manufacture. In the LEBT a high degree of space charge compensation (~90%) and a rise time of space charge compensation around ~ 50 μs could be concluded indirectly from measurements . As a more detailed knowledge is of interest also for other projects like ESS the FETS LEBT was updated to perform a detailed experimental analysis of space charge compensation. In this paper the results of the experimental work will be presented together with discussion of the findings in respect to beam transport. | ||
| MOPPD046 | Lifetime of the Highly Efficient H− Ion Sources | 466 |
|
||
|
Funding: Work supported by grant DE-SC0006267, and STFC JAI grant ST/G008531 Factors limiting operating lifetime of Compact Surface Plasma Sources (CSPS) are analyzed and possible treatments for lifetime enhancement are considered. CSPSs have high plasma density (up to 1014 cm-3), high emission current density of negative ions (up to 8 A/cm2), small (1–5 mm) gap between cathode emitter, and a small extraction aperture in the anode. They are very simple, have high energy efficiency up to 100 mA/kW of discharge (~100 times higher then modern large Volume RF SPS) and have a high gas efficiency (up to 30%) using pulsed valves. CSPSs are very good for pulsed operation but electrode power density is often too high for dc operation. However, CSPSs were successfully adopted for DC operation with emission current density ~300 mA/cm2 in Hollow cathode Penning Discharge and up to 1 A/cm2 in Spherical focusing semiplanotron. Flakes from electrodes sputtering and blistering induced by back accelerated positive ions are the main reasons of ion source failure. Suppression of back accelerated positive ions, flakes explosion by pulsed discharges, and flakes gasification by discharge in NF3 (or XeF2) can be used for significant increase of operating lifetime of CSPSs. |
||
| THPPP051 | Status of the RAL Front End Test Stand | 3856 |
|
||
| The Front End Test Stand (FETS) under construction at RAL is a demonstrator for front end systems of a future high power proton linac. Possible applications include a linac upgrade for the ISIS spallation neutron source, new future neutron sources, accelerator driven sub-critical systems, a neutrino factory etc. Designed to deliver a 60mA H-minus beam at 3MeV with a 10% duty factor, FETS consists of a high brightness ion source, magnetic low energy beam transport (LEBT), 4-vane 324MHz radio frequency quadrupole, medium energy beam transport (MEBT) containing a high speed beam chopper plus comprehensive diagnostics. This paper describes the current status of the project and future plans. | ||