Positron bunching system for producing positronium clouds into vacuum

13th International Workshop on Slow Positron Beam Techniques and Applications

Penasa, L.^1 ; Di Noto, L.^1 ; Bettonte, M.^1 ; Mariazzi, S.^1 ; Nebbia, G.^2 ; Brusa, R.S.^1

Dipartimento di Fisica, Università di Trento, TIFPA-INFN, Via Sommarive 14, Trento, I-38123 Povo, Italy^1

INFN Padova, Via Marzolo 8, 35131 Padova, Italy^2

关键词: Construction solutions;    Cryogenic temperatures;    Electrical circuitries;    Fast switches;    High voltage;    Magnetic transport;    Parabolic potential;    Porous targets;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/505/1/012031/pdf
DOI  :  10.1088/1742-6596/505/1/012031

来源: IOP

【 摘 要 】

A magnetic transport line, a magnetic field terminator and a positron buncher were designed and built to focus low-energy positron pulses from a Surko-type accumulator on a porous target. The 25 electrodes buncher, which produces a parabolic potential, was designed to implant 5 ns positron bunches with a spot of 3 mm into a target held at cryogenic temperature. These pulses will be used to obtain cooled Ps clouds into vacuum for laser excitation in spectroscopy experiments. By using high-voltage fast switches and a proper mu-metal shield the requirement to form Ps in a free (magnetic and electric) field region was satisfied compatibly with the request of injecting positrons at energies of 5-9 keV. The optical design, the electrical circuitry of the buncher and the construction solutions of the whole apparatus will be presented and explained.