13 research outputs found
Simulation Study of Photon-to-Digital Converter (PDC) Timing Specifications for LoLX Experiment
The Light only Liquid Xenon (LoLX) experiment is a prototype detector aimed
to study liquid xenon (LXe) light properties and various photodetection
technologies. LoLX is also aimed to quantify LXe's time resolution as a
potential scintillator for 10~ps time-of-flight (TOF) PET. Another key goal of
LoLX is to perform a time-based separation of Cerenkov and scintillation
photons for new background rejection methods in LXe experiments. To achieve
this separation, LoLX is set to be equipped with photon-to-digital converters
(PDCs), a photosensor type that provides a timestamp for each observed photon.
To guide the PDC design, we explore requirements for time-based Cerenkov
separation. We use a PDC simulator, whose input is the light information from
the Geant4-based LoLX simulation model, and evaluate the separation quality
against time-to-digital converter (TDC) parameters. Simulation results with TDC
parameters offer possible configurations supporting a good separation. Compared
with the current filter-based approach, simulations show Cerenkov separation
level increases from 54% to 71% when using PDC and time-based separation. With
the current photon time profile of LoLX simulation, the results also show 71%
separation is achievable with just 4 TDCs per PDC. These simulation results
will lead to a specification guide for the PDC as well as expected results to
compare against future PDC-based experimental measurements. In the longer term,
the overall LoLX results will assist large LXe-based experiments and motivate
the assembly of a LXe-based TOF-PET demonstrator system.Comment: 5 pages, 7 figure
Experiments with mid-heavy antiprotonic atoms in AEgIS
ments which provide the most precise data on the strong interaction between protons and antiprotons and of the neutron skin of many nuclei thanks to the clean annihilation signal. In most of these experiments, the capture process of low energy antiprotons was done in a dense target leading to a significant suppression of specific transitions between deeply bound levels that are of particular interest. In particular, precise measurements of specific transitions in antiprotonic atoms with Z>2 are sparse.
We propose to use the pulsed production scheme developed for antihydrogen and protonium for the formation of cold antiprotonic atoms. This technique has been recently achieved experimentally for the production of antihydrogen at AEIS. The proposed experiments will have sub-ns synchronization thanks to an improved control and acquisition system. The formation in vacuum guarantees the absence of Stark mixing or annihilation from high n states and together with the sub-ns synchronization would resolve the previous experimental limitations. It will be possible to access the whole chain of the evolution of the system from its formation until annihilation with significantly improved signal-to-background ratio
Monte-Carlo simulation of positronium laser excitation and anti-hydrogen formation via charge exchange
The AEgIS experiment aims at producing antihydrogen (and eventually measuring the effects of the Earth gravitational field on it) with a method based on the charge exchange reaction between antiproton and Rydberg positronium. To be precise,antiprotons are delivered by the CERN Antiproton Decelerator (AD) and are trapped in a multi-ring Penning trap, while positronium is produced by a nanoporous silica target and is excited to Rydberg states by means of a two steps laser excitation. New Monte Carlo simulations are presented in this paper in order to investigate the current status of the AEgIS experiment [1] and to interpret the recently collected data [2]
AEgIS experiment: Towards antihydrogen beam production for antimatter gravity measurements
AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is an experiment
that aims to perform the first direct measurement of the gravitational acceleration g of
antihydrogen in the Earth’s field. A cold antihydrogen beam will be produced by charge
exchange reaction between cold antiprotons and positronium excited in Rydberg states.
Rydberg positronium (with quantum number n between 20 and 30) will be produced by a two
steps laser excitation. The antihydrogen beam, after being accelerated by Stark effect,
will fly through the gratings of a moiré deflectometer. The deflection of the horizontal
beam due to its free fall will be measured by a position sensitive detector. It is
estimated that the detection of about 103 antihydrogen atoms is required to determine the
gravitational acceleration with a precision of 1%. In this report an overview of the AEgIS
experiment is presented and its current status is described. Details on the production of
slow positronium and its excitation with lasers are discussed