An atomic hydrogen beam to test ASACUSA's apparatus for antihydrogen spectroscopy

The ASACUSA collaboration aims to measure the ground state hyperfine splitting (GS-HFS) of antihydrogen, the antimatter pendant to atomic hydrogen. Comparisons of the corresponding transitions in those two systems will provide sensitive tests of the CPT symmetry, the combination of the three discrete symmetries charge conjugation, parity, and time reversal. For offline tests of the GS-HFS spectroscopy apparatus we constructed a source of cold polarised atomic hydrogen. In these proceedings we report the successful observation of the hyperfine structure transitions of atomic hydrogen with our apparatus in the earth's magnetic field.Comment: 8 pages, 4 figures, proceedings for conference EXA 2014 (Exotic Atoms - Vienna

The ASACUSA antihydrogen detector : development and data analysis

Zusammenfassung in deutscher SpracheDie theoretische Beschreibung der Natur im Rahmen des Standardmodells der Teilchenphysik enthält eine Vielzahl an Symmetrien. Die fundamentalste ist die kombinierte Symmetrie aus Ladungsumkehr-, Paritäts- und Zeitumkehrsymmetrie (CPT Symmetrie). Nach allen verfügbaren experimentellen Befunden wurde bisher keine Verletzung dieser Symmetrie gefunden. Die ASACUSA Kollaboration am "Antiproton Deceleator" der Europäische Organisation für Kernforschung, CERN, versucht Übergänge in der Hyperfeinstruktur im Grundzustand von Antiwasserstoff zu messen. Antiwasserstoff ist das leichteste Element das vollständig aus Antimaterie besteht. Durch den Vergleich der Übergangsfrequenzen mit seinem Materie-Äquivalent, Wasserstoff, erlaubt diese Messung ein direktes Testen der CPT Symmetrie. Im Rahmen dieser Dissertationsschrift wurde ein Detektorsystem entwickelt, um die Annihilation der Antiatome am Ende des experimentellen Aufbaus nachzuweisen. Im Rahmen der vorliegenden Arbeit wird der vollständige Aufbau des Detektors, inklusive der Datenerfassung und Steuerung beschrieben. Besonders Augenmerk wird auf die Elektronik des Systems, die Funktionsweise der Datenaufnahme und die Struktur der gemessenen Daten gelegt. Mit dem Detektorsystem aufgezeichnete Daten wurden mittels bayesianischer Methoden analysiert. Es wird sowohl die Identifikation der Annihilationen und ihre Unterscheidung von Untergrundereignissen, als auch die tatsächliche statistische Analyse im Detail erläutert. Abschließend wird, aufbauend auf die statistische Analyse, die Signifikanz der erhobenen Daten und der Nachweis von Antiwasserstoff-Annihilationen im Detektor präsentiert.The theoretical description of nature, within the standard model framework of particle physics, gives rise to a manifold of different symmetries. The most fundamental one is the combined symmetry of charge conjugation, parity transformation, and time reversal (CPT symmetry). Currently all experimental evidence opposes the idea of a broken CPT symmetry. The ASACUSA collaboration, at the "Antiproton Decelerator", at the European Organisation for Nuclear Research (CERN), tries to measure the ground state hyperfine splitting of antihydrogen. By comparing this splitting with the similar signal in ordinary hydrogen, the CPT symmetry can be directly tested. During the course of this thesis, a detector system for detecting annihilations from antihydrogen at the end of the experimental setup was developed. In this work the construction of the detector will be described in detail, including control and data acquisition of the setup. A special focus will be on the electronic components, the inner working of the data acquisition, and the structure of the measured data. The recorded data was analysed using Bayesian methods. Both, the identification of annihilation events and their consequent distinction from background signals, and the statistical analysis of the data are covered in detail. Finally, based on the statistical analysis, the data significance is presented.10

waveformlibrary v1.0.0

<p>This is the first release of the SMI waveform library.</p> <p><strong>The highlights of this release are</strong>:</p> <ul> <li>reader class for TTrees in ROOT files</li> <li>reader class for MIDAS files using</li> <li>fully implemented plugin system</li> </ul> <p><strong>Available analyser plugins</strong>:</p> <ul> <li>pulse type detection, detect if signal is a positive or negative pulse</li> <li>select ADC range</li> <li>subtract baseline</li> <li>calculate mean and standard deviation within a gate</li> <li>calculate charge within a gate</li> <li>leading edge time stamp with linear interpolation</li> <li>constant fraction time stamp with linear interpolation</li> <li>repeat constant fraction calculation for many different fractions</li> <li>fit precomputed waveform templates and extract pulse height and time stamp</li> </ul

Annihilation detector for an in-beam spectroscopy apparatus to measure the ground state hyperfine splitting of antihydrogen

The matter-antimatter asymmetry observed in the universe today still lacks a quantitative explanation. One possible mechanism that could contribute to the observed imbalance is a violation of the combined Charge-, Parity- and Time symmetries (CPT). A test of CPT symmetry using anti-atoms is being carried out by the ASACUSA-CUSP collaboration at the CERN Antiproton Decelerator using a low temperature beam of antihydrogen—the most simple atomic system built only of antiparticles. While hydrogen is the most abundant element in the universe, antihydrogen is produced in very small quantities in a laboratory framework. A detector for in-beam measurements of the ground state hyperfine structure of antihydrogen has to be able to detect very low signal rates within high background. To fulfil this challenging task, a two layer barrel hodoscope detector was developed. It is built of plastic scintillators with double sided readout via Silicon Photomultipliers (SiPMs). The SiPM readout is done using novel, compact and cost efficient electronics that incorporate power supply, amplifier and discriminator on a single board. This contribution will evaluate the performance of the new hodoscope detector