Research of Emittance Matching on the Low Energy Beam Transport Line for ADS Proton LINAC

Key words: 
• ADS accelerator /
• ECR proton source /
• LEBT /
• emittance

Abstract: An intense ECR proton source and low energy beam transport (LEBT) system have been developed for the proton Linac of China Initiative Accelerator Driven Sub-Critical system (C-ADS). The proton source can deliver stable 35 keV proton beams to the entrances of the downstream Radio-Frequency Quadrupole (RFQ). The optics mismatching between the LEBT sections is the main reason that leads to the beam loss in the intense RFQ. Optimum beam matching between the different accelerator sections is one of the key points to reduce the beam losses and emittance growth. For CI-ADS driver Linac system, beam loss at continuous wave operation mode leads to thermal deformation and sparks in the RFQ, and thus has big impact to the reliability of RFQ. Therefore, this paper was mainly studied how to achieve good beam matching and reduce beam losses between LEBT and RFQ. Experiments study show that beam emittance at the LEBT exit is less than 0.2 mm
mrad when the 10 mA/35 keV was extracted from the LEBT. The emittance meets the matching requirement of the RFQ entrance when the currents of solenoids lens were sets to 210 and 270 A.