Transport beam line for ultraslow monoenergetic antiprotons

Abstract

A beam line for the transportation of slow antiprotons from a multiring electrode trap to an experimental chamber is described. The beam line is equipped with a three-stage differential pumping system in order to maintain a pressure lower than 1×10−12 Torr in the trap region while simultaneously having a pressure of around 1×10−6 Torr in the chamber. Tests have shown that 105 positive ions per trapping cycle were successfully extracted at 250 eV from the trap positioned in a superconducting solenoid. The ions were then further transported through three small apertures to the target area located 3.5 m downstream of the trap. Results from the first delivery of a 250 eV antiproton beam are described.

Ionization of Helium and Argon by Very Slow Antiproton Impact

“…After cooling, the electrons were ejected, and the pure antiproton cloud was compressed [5]. The antiprotons were then extracted as a 250 eV dc beam by slowly ramping up the trapping potential and transported to a magnetic-field-free region through x and y deflectors and electrostatic lenses with three differential pumping stages separated by apertures [6]. The number of antiprotons transported to the end of the differentially pumped beam line was typically 6-7 10 5 per AD shot.…”

ASACUSA MUSASHI: New progress with intense ultra slow antiproton beam

“…We utilize a RFQD (Radio Frequency Quadrupole Decelerator) and a multiring-electrode trap (MRT) placed in a 5-T magnetic field; this trap stores, cools and ejects a large number of antiprotons. Recently, we succeeded in accumulating more than 10 7 antiprotons in the MRT and in providing slow-or pulse-extracted beam of approximately 10 6 antiprotons per 1 AD shot [3][4][5].…”

Observation of Ultra-Slow Antiprotons using Micro-channel Plate

“…In this system, the multiring-electrode trap [4] for accumulating antiprotons was placed in a 5-T magnetic field. Then, the antiprotons were extracted and delivered to downstream passing through a transport beamline for differential pumping [5]. Then, the antiprotons were extracted and delivered to downstream passing through a transport beamline for differential pumping [5].…”