Abstract The PADME experiment is designed to search for a hypothetical dark photon A ' produced in positron-electron annihilation using bunched positron beam at the Beam Test Facility of INFN Laboratori Nazionali di Frascati. expected sensitivity -photon mixing parameter ? 10 -3 , mass ? 23.5 MeV/ c 2 after collecting ? 13 positrons-on-target. This paper presents detector status commissioning J...

Absolute cross sections for the vibrational excitation of CO, CO2, and H2 by positron impact are presented for incident positron energies from 0.5 eV to several electron volts. The measurements use a novel technique that exploits the adiabatic motion of a positron beam in a strong magnetic field. This work is the first systematic experimental study of vibrational excitation by positron impact, ...

In recent years slow positron beam physics has become a very active and diverse field [1] . Currently under consideration are several applications of slow positron beams which require intense beams (>_ 1 Ci of e + ) for their success. A partial list of such applications includes : the production and study of antihydrogen [2], the use of positrons in synchrotron light sources [3], positron micro...

The recent development of Accelerator-based Gamma-induced Positron Annihilation Spectroscopy (AGPAS) has shown the possibility of probing residual stress in thick materials by Doppler broadening measurements [1]. In those measurements, the residual stresses were reflected in the line shape parameters of the 511 keV annihilation peak. However, since positron lifetime spectroscopy is a powerful t...

Linear colliders, such as the SLC, are among those accelerators for which a high-yield positron source operating at the repetition rate of the accelerator is desired. The SLC, having electron energies up to 50 GeV, presents the possibility of generating positron bunches with useful charge even exceeding that of the initial electron bunch. The exact positron yield to be obtained depends on the p...

The local pulsar and its progenitor, SNR, can together accelerate the positron, electron nuclei to very high energy. famous excesses of positron(nuclei) above $20$($200$) GeV possibly come from such kind source. This hints that primary should also hold "excess" $200$ GeV, synchronously accelerated along with nuclei. recent precise measurement sharp dropoff at 284 positron by AMS-02 experiment t...

Recent experiments and simulations have shown that positron beams propagating in plasmas can be focused and also create wakes with large accelerating gradients. For similar parameters, the wakes driven by positron beams are somewhat smaller compared to the case of an electron beam. Simulations have shown that the wake amplitude can be increased if the positron beam is propagated in a hollow pla...

As a nuclear approach, Positron Emission Tomography (PET) is a functional imaging technique which is based on the detection of gamma ray pairs emitted by a positron-emitting radionuclide. There are certain limitations to this technique such as normal tissue uptake. Therefore, it has been recommended that patients prepare before scanning. Fasting for a short while before PET imaging is an exampl...

Division of Medical Physics, University of Leeds, UK Positron range is an important spatial resolution limiting factor in PET. When imaging inside a magnetic field the positron range is non-uniformly affected. A decrease of the positron range is expected in the directions perpendicular to the direction of the magnetic field, whereas no variation is expected in the direction of the magnetic fiel...

Abstract Nanochanneled silicon targets with high positron/positronium (Ps) conversion rate and efficient Ps cooling were produced. Morphological parameters of the nanochannels, such as their diameter length, adjusted to get a large fraction thermalized at room temperature being emitted into vacuum. measurements conducted combining single-shot positron annihilation lifetime spectroscopy Doppler ...