TRIUMF/VECC E-LINAC INJECTOR BEAM TEST R.E. Laxdal, F. Ames, Y.C. Chao, K. Fong, C. Gong, A. Laxdal, M. Marchetto, W.R. Rawnsley, J. Abernathy, D. Karlen, D. Storey, U. of Victoria, Victoria, Canada V. Naik, A. Chakrabarti, VECC, Kolkata, India Abstract TRIUMF is collaborating with VECC on the design of a 10 MeV injector cryomodule to be used as a front end for a high intensity electron linac. A electron gun and low energy beam transport (LEBT) have been installed in a test area to act as the injector for the cryomodule test. The LEBT includes a wide variety of diagnostics to fully characterize the beam from the gun. A series of beam tests are being conducted during the stage installation. The test configuration details and results of beam tests will be presented. INTRODUCTION TRIUMF is now preparing a new high intensity (10mA) 50MeV superconducting electron linear accelerator [1], e-Linac, as a key element of the ARIEL project. In brief the e-Linac consists of five 1.3GHz nine- cell niobium cavities each providing 10MV acceleration with two 50kW power couplers supplying the required beam loaded rf power. The five cavities are housed in three cryomodules, with a single cavity in an injector cryomodule, EINJ, and two identical accelerating cryomodules EACA and EACB with two cavities in each module. TRIUMF began developing EINJ in 2010 in collaboration with the VECC laboratory in Kolkata. As part of the collaboration two EINJs will be fabricated and beam tested at TRIUMF. One EINJ will be shipped and installed at VECC and the second will be installed in the e-Linac. The initial EINJ is presently in fabrication [2]. A beam test area is being installed in the ISAC-II building to eventually test the two injector cryomodules with beam. The site utilizes the existing ISAC-II cryogenics infrastructure and enables testing of the cryomodules well before the expected availability of the e-Linac cryogenics in 2014. The schedule calls for accelerated beam tests in early 2013. Moreover, the injector test facility provides an ideal proving ground for e-linac design and operation strategies. It duplicates the front-end of the e-linac up to the exit of the injector cryomodule with enhanced diagnostics capability for benchmarking both the performance of the gun but also of the various diagnostics themselves. In addition the test installation allows early demonstration and troubleshooting of various e-Linac sub-systems including MPS, controls, beam modes, safety, LLRF, HPRF, cryogenics and important feedback on beam quality, halo formation and high intensity operation. Commissioning this facility began Nov 2011. INJECTOR LAYOUT The test layout, shown in Fig. 1 includes an electron gun, a low energy beam transport (LEBT) complete with a beam diagnostics leg, the EINJ cryomodule, a medium energy beam transport and diagnostic end station (MEBT) and beam dump. Two guns are envisaged. In the first phase (present) a 100kV thermionic gun with rf modulated gridded cathode bias is utilized. The cathode rf drive is at 650MHz providing rf bunches for one of every two accelerating buckets. This will soon be replaced by a 300kV gun also with rf modulated gridded cathode bias at 650MHz. The higher energy is needed to achieve efficient capture in the EINJ while the 100kV gun is perfectly sufficient to characterize the rf modulation and commission the LEBT and diagnostics. In both cases the specified peak current is 10mA, with a bunch length of ≤±20 0 of 650 MHz (170 ps), a bunch charge of 15.3 pC, an energy spread of ≤ ±1 keV and a transverse emittance of ≤ 30 μm normalized to a 2σ x 2σ cylindrical beam.The rf modulation can also be pulsed to provide a macro duty cycle varying from 0.1% to 99.9% duty cycle at various macro periods. Figure. 1: TRIUMF/VECC beam test configuration. The LEBT straight section is designed to prepare the beam for acceleration. Three solenoids are used to provide transverse matching and transportation. An initial solenoid provides a waist at the buncher while the two downstream solenoids match the beam to the cryomodule. A 1.3GHz room temperature buncher provides longitudinal matching to the EINJ. An analyzing diagnostic line includes a 90 0 bending spectrometer, diagnostic boxes and a 1.3GHz rf deflector for bunch length measurements. DIAGNOSTICS The diagnostics used in the LEBT are shown in Fig. 2. The diagnostics fit in multi-port custom chambers machined out of solid stainless steel bulk material. The S. Saminathan, V. Verzilov, Q. Zheng, V. Zvyagintsev, TRIUMF, Vancouver, Canada Proceedings of LINAC2012, Tel-Aviv, Israel MOPB026 01 Electron Accelerators and Applications 1A Electron Linac Projects ISBN 978-3-95450-122-9 231 Copyright c ○ 2012 by the respective authors — cc Creative Commons Attribution 3.0 (CC BY 3.0)