Increase in the beam intensity of the linac-based slow positron beam and its application at the Slow Positron Facility, KEK

New experiment stations at KEK Slow Positron Facility

“…About a half of the transported positrons went through a magnetic lens placed in the magnetic-field-free region, a φ10 mm aperture, a set of Einzel lens, and a φ3 mm × 30 mm collimator, then reached the sample. The observed specular intensity was 14 times intensified [1] over the former measurements with the 22 Na-based beam at JAEA.…”

“…It operates in two pulse modes: the long pulse mode of 1 μs pulse width, and the short pulse mode of variable 1-10 ns pulse width. In October 2010, a new positron converter and moderator assembly was introduced, yielding an increase of an order of magnitude in the intensity of the beam [1]. The long pulse The experiment hall of the facility consists of two floors.…”

“…RHEPD was proposed by A. Ichimiya [7] and was brought into practical use by Kawasuso and Okada [8] with a 22 Na-based slow-positron beam at Japan Atomic Energy Agency (JAEA). In 2010, a RHEPD station was installed at the end of the beam-line branch SPF-B1 in KEK-IMSS-SPF [1]. Magnetically transported positrons with an energy of 10 keV were introduced into the magnetic-field-free region, which were isolated from the magnetic field of the transportation coils by a 3 mm thick iron plate.…”

Observation of Low-Energy Positron Diffraction Patterns with a Linac-Based Slow-Positron Beam

“…The Slow Positron Facility (SPF) at the Institute of Materials Structure Science (IMSS) in KEK provides a high-intensity pulsed slow-positron beam generated using a dedicated normal-conducting linac operated at ∼50 MeV, < 0.6 kW with a repetition frequency of 50Hz [18,19]. Accelerated electrons are impacted on a tantalum (Ta) plate and deflected in the electric field around the Ta atom, emitting Bremsstrahlung X-rays.…”

Production of positrons via pair creation from LCS gamma-rays and application to defect study in bulk materials

“…In recent years, many positron beam facilities, such as positron micro-beam, polarized positron beam, positronium time of flight spectroscope and positron microscope, have been constructed and developed [6][7][8][9][10][11]. Typically, the maximum positron energy is a few tens of keV at these positrons beamlines.…”