Master thesis in experimental particle physics – Study of antiproton annihilations at CERN
The Stefan Meyer Institute for Subatomic Physics (www.oeaw.ac.at/smi) is currently looking for a Master student for the antihydrogen group (www.antimaterie.at) which is part of the ASACUSA collaboration at CERNs Antiproton Decelerator. Additionally to our measurement of the ground state hyperfine splitting of antihydrogen [1], a study of antiproton annihilations with different materials is planned.
Antiproton annihilations are not well understood, none of the available annihilation simulation models can reproduce the experimental results in low energy regions. Thus, it is important for the understanding of antiproton annihilations and theoretical descriptions to study these annihilations experimentally.
During this years beamtime, it is planned to use an array of Timepix [2] detectors surrounded by ASACUSAs tracking detector which consists of a two layered hodoscope [3] to record the annihilation signals on foils of different materials.
This master thesis:
The goal of this master thesis is to study these foils for surface contaminations and determine the needed dimensions with a test experiment using protons and simulations. Also, longer stays (few weeks) at CERN for the antiproton study will be included (travel expenses will be covered by the institute).
Requirements: Solid knowledge of particle physics and programming skills (C/C++) are welcome. Good language skills (English) are helpful
Planned start: Summer 2017
Contact: Prof. Eberhard Widmann (eberhard.widmann@oeaw.ac.at)
References:
[1] E. Widmann et al. (2013). Measurement of the hyperfine structure of antihydrogen in a beam. Hyperfine Interactions, 215, 1–8
[2] medipix.web.cern.ch/medipix/pages/medipix2/timepix.php
[3] C. Sauerzopf et al. (2016). Annihilation Detector for an In-Beam Spectrsocopy Apparatus to Measure the Ground State Hyperfine Splitting of Antihydrogen. NIM A. doi.org/10.1016/j.nima.2016.06.023
Graduate School “Particles and Interactions” DKPI
The graduate school DKPI – “Particles and Interactions” is accepting applications for Ph.D. students. The topics include the HbarHFS program. Details can be found at http://www.dkpi.at/. For questions please contact eberhard.widmann@oeaw.ac.at.
Ph.D. project in Antihydrogen Research at SMI: Measurement of the pi1 hyperfine transition in hydrogen and antihydrogen
The PhD thesis will take place within the ASACUSA collaboration which aims at measuring the ground state hyperfine splitting GS-HFS of antihydrogen. Antihydrogen is formed at the Antiproton Decelerator (AD) at CERN by mixing slowed-down antiprotons with a cloud of positrons. ASACUSA aims at forming a beam of antihydrogen to perform in-flight spectroscopy of ground state antihydrogen [1]. By comparison with hydrogen, this measurement could provide one of the most sensitive tests of CPT symmetry [2, 3].
The first antihydrogen beam formation was reported by the ASACUSA collaboration this year [4], and further progress is expected during a few weeks of beam time in the end of 2014. In parallel a source of polarized hydrogen atoms was developed and measurements of one of two possible hyperfine transitions, the sigma1 transition, were made in a small external magnetic field created by a pair of Helmholtz coils. Measurements of the GS-HFS of hydrogen could be made with a precision better the 10–8. In order to measure the second transition pi1, which is much more sensitive to magnetic field inhomogeneities, new coils and correction coils have to be designed, built, and tested. Using these coils systematic measurements with the hydrogen beam to characterize the apparatus and afterwards with antihydrogen will be performed.
The candidate should have good experimental skills, both in numerical simulations as well as lab work.
The work can in the first place be performed at the Stefan Meyer Institute for Subatomic Physics in Vienna. Several months stay at CERN are necessary for data-taking periods and analysis.
[1] E. Widmann et al., Hyperfine Interactions, (2012) doi:10.1007/s10751-013-0809-6
[2] D. Colladay, V.A. Kostelecky, Physical Review D 55,6760 (1997)
[3] R. Bluhm, V. Kostelecky, N. Russell, Physical Review Letters 82 (11), 2254 (1999)
[4] N. Kuroda et al., Nature Communications (2014) doi: 10.1038/
Ph.D. project in Antihydrogen Research at SMI: Bayesian statistical analysis
The PhD thesis will take place within the ASACUSA collaboration which aims at measuring the ground state hyperfine splitting of antihydrogen. Antihydrogen is formed at the Antiproton Decelerator (AD) at CERN by mixing slowed-down antiprotons with a cloud of positrons. Unlike two other experiments at the CERN AD, which trap antihydrogen atoms in strong magnetic bottles, the ASACUSA experiment forms a beam of antihydrogen to perform in flight spectroscopy of ground state antihydrogen [1]. This method has the advantage of not requiring ultra cold (less than 0.5K) antihydrogen and be free of the disturbance generated by strong magnetic fields. The beam method can in principle reach a precision of 10–6 if enough statistics can be gathered. At this level of precision, and by comparison with hydrogen, this measurement could provide one of the most sensitive tests of CPT symmetry [2, 3].
The first antihydrogen beam formation was reported by the ASACUSA collaboration this year [4]. This is the first step towards an in-flight spectroscopy of antihydrogen. However due to the difficulties inherent to the production of antihydrogen, the current antihydrogen rate is limited. Furthermore, antihydrogen are not produced in Rydberg states and decay in flight on their way to the spectroscopy apparatus. The challenge is thus to extract a precise measurement of the ground-state hyperfine splitting given a large amount of background from excited stated and reduced statistics. Detailed geant4 simulations of the complete setup have been made [5] and will be improved in order to evaluate the impact of the different backgrounds on the achievable precision.
The goal of this PhD thesis would be to develop a Baeysian statistical analysis in order to combine the information collected by different detectors and simulation data to extract the best possible sensititvity with the available low statistics. In the first place, the full analysis can be developed with Monte Carlo toy data. First experimental data including the full spectroscopy apparatus are expected in 2014 and in larger amount in 2015.
The candidate should have good programming knowledge, in particular in C++. Knowledge of Geant4 would be preferable but is not required.
The work can in the first place be performed at the Stefan Meyer Institute for Subatomic Physics in Vienna.Several months at CERN are envisioned for data-taking periods and analysis.
[1] E. Widmann et al., Hyperfine Interactions, (2012) doi:10.1007/s10751-013-0809-6
[2] D. Colladay, V.A. Kostelecky, Physical Review D 55,6760 (1997)
[3] R. Bluhm, V. Kostelecky, N. Russell, Physical Review Letters 82 (11), 2254 (1999)
[4] N. Kuroda et al., Nature Communications (2014) doi: 10.1038/ncomms4089
[5] C. Malbrunot et al. Hyperfine Interactions (Feb. 2014) doi:10.1007/s10751-014-1013-z
Other thesis subjects available at SMI
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Bachelorarbeit
Simulation zur Messung der Hyperfeinstruktur von Antiwasserstoff
Antiwasserstoff [1] ist das leichteste Atom, dass vollständig aus Antimaterie besteht. Daher ist es ein idealer Kandidat um die grundlegendste Symmetrie in der Teilchenphysik, die CPT (Charge, Parity and Time) Symmetrie, zu testen. Die im Rahmen der ASACUSA Collaboration [2,3] am europäischen Kernforschungszentrum (CERN) durchgeführten Experimente versuchen durch Präzisionsmessungen die Brechung oder den Erhalt der Symmetrie zu untersuchen und damit, auf lange Sicht, die Frage nach dem Ungleichgewicht zwischen Materie und Antimaterie zu beantworten. In einer CPT symmetrischen Welt entsteht immer gleich viel Materie und Antimaterie warum also finden wir keine größeren Mengen Antimaterie im Universum und warum gibt es überhaupt Materie?
Die Durchführung von Präzisionsmessungen erfordert ein Höchstmaß an Verständnis des experimentellen Aufbaus, daher sind genaue und zuverlässige Simulationen unabdingbar. Im Rahmen einer Projekt- oder Bachelorarbeit bieten wir die Möglichkeit, Erfahrungen mit dem Simulationstoolkit Geant4 [4], der statistischen Analysebibliotheken ROOT [5] und den gängigsten Austauschformaten für Detektorgeometrien wie GDML, zu sammeln. Der Umfang der Arbeit wird an den verfügbaren Zeitrahmen und an die Interessenslage angepasst.
Anforderungen:
* gute Kenntnisse in C++
Die Arbeit wird am Stefan-Meyer-Institut für subatomare Physik (SMI) in der Boltzmanngasse 3 durchgeführt. http://www.oeaw.ac.at/smi
Contact eberhard.widmann@oeaw.ac.at
[1] http://www.antimaterie.at
[2] Kuroda et.al. A Source of Antihydrogen for in-Flight Hyperfine Spectroscopy, Nature Communications 5, 3089 (2014) (http://dx.doi.org/10.1038/ncomms4089)
[3] asacusa.web.cern.ch
[4] http://geant4.web.cern.ch
[5] root.cern.ch
Masterarbeit
Detektorentwicklung zum Nachweis von Antiwasserstoff
Antiwasserstoff [1] ist das leichteste Atom, dass vollständig aus Antimaterie besteht. Daher ist es ein idealer Kandidat um die grundlegendste Symmetrie in der Teilchenphysik, die CPT (Charge, Parity and Time) Symmetrie, zu testen. Die im Rahmen der ASACUSA Collaboration
[2,3] am europäischen Kernforschungszentrum (CERN) durchgeführten Experimente versuchen durch Präzisionsmessungen die Brechung oder den Erhalt der Symmetrie zu untersuchen und damit, auf lange Sicht, die Frage nach dem Ungleichgewicht zwischen Materie und Antimaterie zu
beantworten. In einer CPT symmetrischen Welt entsteht immer gleich viel Materie und Antimaterie warum also finden wir keine größeren Mengen Antimaterie im Universum und warum gibt es überhaupt Materie?
Aufgrund der großen Schwierigkeiten bei der Erzeugung von Antimaterie-Atomen ist es notwendig eine möglichst gute Identifikation der Antiwasserstoff-Annihilationen zu erreichen. Im Rahmen einer Diplomarbeit besteht die Möglichkeit bei der Konstruktion und dem Testen eines Detektors zum Nachweis von Antimaterie mitzuarbeiten. Die Aufgaben umfassen je nach Interessenslage, das Testen und Kalibrieren der einzelnen Detektorelemente, die Entwicklung der Triggerlogik mittels eines FPGAs (Field Programmable Gate Array), Entwicklung und Verbesserung der Datenerfassung (DAQ) und Experimentsteuerung (slow control) oder der Verbesserung und Entwicklung von Routinen zur Datenanlyse.
Wie bieten:
* Mitarbeit in einer internationalen Collaboration (ASACUSA)
* die Möglichkeit eines CERN Aufenthalts im Rahmen des Experiments
Anforderungen:
* Interesse an praktischer Arbeit (Testen und Kalibrieren des Detektors)
* vorteilhaft aber nicht zwingend erforderlich: Programmierkenntnisse (C, C++, VHDL)
* vorteilhaft aber nicht zwingend erforderlich: Erfahrung mit Datenanlyse und Signalverarbeitung
Ort:
Die Arbeit wird am Stefan-Meyer-Institut für subatomare Physik (SMI) in der Boltzmanngasse 3 durchgeführt. http://www.oeaw.ac.at/smi
Contact eberhard.widmann@oeaw.ac.at
[1] www.antimaterie.at
[2] Kuroda et.al. A Source of Antihydrogen for in-Flight Hyperfine
Spectroscopy, Nature Communications 5, 3089 (2014)
(http://dx.doi.org/10.1038/ncomms4089)
[3] asacusa.web.cern.ch