Feasibility and conceptual design of a C.W. positron source at CEBAF

Thesis/Dissertation · Sun Aug 01 00:00:00 EDT 2010

DOI:https://doi.org/10.2172/1004757· OSTI ID:1004757

Golge, Serkan ^[1]

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1. Old Dominion Univ., Norfolk, VA (United States)

A feasibility study of a CW positron source for the 12 GeV upgrade at Jefferson Lab (JLAB) is provided. The proposed ≥ 100 nA Continuous Wave (CW) positron source at JLAB has several unique and challenging characteristics: high current incident electron beam at 126 MeV with a high beam power (up to a MW); CW e^- beam and CW e⁺ production. The multiple scattering is a dominant process when creating e⁺ in a target, which results a large phase space area of the emitted positrons. An admittance study was done at CEBAF to find the maximum phase space area, which is tolerated in the machine. The measured geometrical transverse admittance (A) were A_x =10 and A_y = 5 mm∙mrad at the injector. Energy spread measurement was also done at the ARC1. The fractional spread limit in the ARC1 was measured as δ = 3×10^-3 at 653 MeV. By using the optimized results and the CEBAF parameters, three positron injector configurations are proposed; Combined Function Magnet, Two-Dipole and Microtron Dipole configurations. With the assumptions made, by using 126 MeV Ⓧ10 mA e^- beam impinging on a 2 mm W target with a 100 μm spot size, we can get up to 3 μA useful e⁺ current at the North Linac connection. One of the biggest challenges is the target design, which the deposited power is about 60 kW. ILC designs project power deposition up to 13 kW, which would allow the creation of a e⁺ beam of up to 650 nA otherwise. The results of analytic and monte carlo simulations of the positron production, capture and acceleration are presented. For the target design, a review is presented of solutions for the high power production target. Portions of this dissertation work have been published in two conference proceedings.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1004757
• Report Number(s): JLAB-ACP-10-1301; DOE/OR/23177-1458; TRN: US1101057
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATION
DEPOSITION
DESIGN
DIPOLES
ELECTRON BEAMS
LINEAR ACCELERATORS
MICROTRONS
MULTIPLE SCATTERING
PHASE SPACE
POSITRON SOURCES
POSITRONS
POWER GENERATION
PRODUCTION
TARGETS