STATUS OF THE RAL FRONT END TEST STAND
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.
Modulator systems for the ESS 2.5 MeV fast chopper
Modulator system requirements for the ESS 2.5 MeV slow wave chopper are considered to be challenging. A description is given of candidate modulation schemes, and modulator configurations, where the chopper E-field is generated by a gated high frequency sinusoidal/trapezoidal waveform or by a combination of fast transition short duration, and slow transition long duration, trapezoidal pulses.
MEASURED PERFORMANCE OF THE ISIS RFQ
The ISIS RFQ is a 665 keV, 202.5 MHz, 4-rod RFQ intended as a replacement pre-injector for the ISIS spallation neutron source at RAL. A test facility has been constructed for soak testing and characterising of the RFQ before installation. Results are presented for measurements of the principal parameters of the RFQ together with its performance characteristics. A comparison is made between the measurements and the results from computer simulations. 1 THE ISIS RFQ TEST FACILITY The RFQ test facility is described in detail in [1][2]. An ISIS Penning ion source [3][4][5] produces a 30 mA beam of 35 keV H-minus ions which are matched into the RFQ by a three solenoid magnetic low energy beam transport (LEBT)[6][7]. A 202.5 MHz 4-rod RFQ [8][9] accelerates the beam to 665 keV using ~200 kW of RF power. Toroidal beam current transformers (BCTs) are installed at the ion source output and RFQ input at 35 keV as well as at the output and ~1m downstream of the RFQ at 665 keV. Time resolved emittance measurements are made using slit and cup scanners [10] upstream and downstream of the RFQ. A gas scattering energy analyser [11][12] is installed in an external beamline. Diagnostics soon to be installed include a magnetic spectrometer and a coaxial fast Faraday cup for bunch length investigations.