Ion Beam Emittance Measurements of Proton Injector for Compact Neutron Source DARIA

Abstract

This article is devoted to measurement of proton beam parameters as one of the stages of proton injector for linear accelerator of compact neutron source DARIA development. Experimental results of ion source operating modes investigation are presented in this work. Gasdynamic electron-cyclotron resonance ion source GISMO is used as a proton injector. The plasma of the ion source is characterized as dense (the electron density is about 10¹³ cm^–3) and hot (the electron temperature is about 30 eV). High volumetric energy input in plasma (up to 250 W cm^–3) is achieved by the use of powerful “technological” gyrotron radiation to the plasma heating. The total ion beam current and beam emittance measurements were conducted during experiment at different facility parameters: inlet gas pressure, microwave power, magnetic lens current, and extraction voltage. The beam emittance was measured using pepper-pot method. The optimal ion source operation mode was found. The total beam current was above 100 mA at the proton beam energy of 40 keV, and the root-mean square normalized emittance was 0.21 π mm mrad. The obtained results of measurements are beneficial from the point of view of possibilities to control the ion source operating modes.