Show simple item record

dc.contributor.author
Epprecht, Lukas
dc.contributor.supervisor
Rubbia, André
dc.contributor.supervisor
Wallny, Rainer
dc.date.accessioned
2017-11-17T15:16:20Z
dc.date.available
2017-06-10T13:57:14Z
dc.date.available
2017-11-17T15:16:20Z
dc.date.issued
2012
dc.identifier.uri
http://hdl.handle.net/20.500.11850/63614
dc.identifier.doi
10.3929/ethz-a-009759662
dc.description.abstract
With today's understanding of the Universe, a large quantity of non luminous matter is necessary to describe several cosmological eects. This so called Dark Matter (DM) is hunted, among others, with the Argon Dark Matter experiment (ArDM). ArDM aims at a direct detection of the nuclear recoil from a collision of a (hypothetical) DM particle with an argon nucleus. ArDM is a liquid argon double phase time projection chamber (TPC) with calorimetric capabilities. The detector has a ducial volume of about 800 l of highly puried liquid argon, combined with a charge readout system in the argon vapor above the liquid surface. Besides the detection of the ionization charge, ArDM also has a highly sensitive light readout system. It is capable of reading out single photoelectrons and, therefore, to quantify the emitted argon scintillation light from the interaction between an entering particle and the argon atoms. This allows to measure the recoil energy and to discriminate between electron and nuclear recoils, yielding a clue to the nature of the interacting particle and allowing to suppress background events. The topic of this thesis is the design, construction and commissioning of the ArDM detector at CERN. It describes the development of the dierent sub-detectors and the technical and physics challenges faced in their construction. Having a good knowledge of the electric drift eld is important for the operation of a TPC. It has to be uniform and constant, with a known eld strength, in order to be able to evaluate the drift distance from the primary interaction to the readout of the ionization electrons. The high voltage needed in ArDM to maintain the electric eld over a drift distance of more than one meter is rather big and providing the source for this HV is a major challenge. Instead of a standard power supply, a Greinacher high voltage generator was developed. First results of a 210 stages Greinacher circuit, operated in liquid argon, are discussed. Also essential for the operation of a cryogenic experiment are the facilities to keep the liquid gas at stable pressure and temperature. Dierent topics like the insulation vacuum and cooling of the experiment are described. For safety reasons, the experiment is built as a zero loss experiment, which means there is no argon nor other gas escaping from the closed system. For this purpose, two cryocoolers are installed and a constant liquefaction of the argon vapor has to be maintained. An ecient operation of the TPC can only be achieved if the contamination of the liquid argon with electronegative molecules, like oxygen or water, is very well controlled and kept below one part per billion (1 ppb). For this reason, the detector material has to be cleaned of the above mentioned molecules. This calls for an initial evacuation of the setup for several months to reduce the outgassing of these molecules to an acceptable level. A detailed look on the outgassing properties of dierent materials is given in this work. Also, the active recirculation and purication of the liquid, and the argon vapor are discussed. Because ArDM is aiming for the detection of very rare events, the control of the background is essential. To reduce the unwanted interactions of cosmic muons with the argon atoms, the experiment has to be installed in a low background environment. This was found in the underground laboratory of Canfranc, Spain (LSC). After several commissioning runs on the surface at CERN, the experiment was dismantled and the cryogenic facilities were moved to this underground laboratory. In this thesis, the installation and rst results from the commissioning of the insulation vacuums and the cryogenic facilities are discussed.
en_US
dc.format
application/pdf
dc.language.iso
en
en_US
dc.publisher
ETH
en_US
dc.rights.uri
http://rightsstatements.org/page/InC-NC/1.0/
dc.subject
FEHLERRECHNUNG + AUSWERTUNG + INTERPRETATION (PHYSIK)
en_US
dc.subject
CALIBRATION AND TESTING OF INSTRUMENTS (PHYSICS)
en_US
dc.subject
DATA EVALUATION + ERROR CALCULATION (PHYSICS)
en_US
dc.subject
DUNKLE MATERIE (ASTRONOMIE)
en_US
dc.subject
COUNTERS AND DETECTORS OF PARTICLES AND QUANTA (NUCLEAR METHODS)
en_US
dc.subject
EICHUNG UND PRÜFUNG VON MESSGERÄTEN (PHYSIK)
en_US
dc.subject
DARK MATTER (ASTRONOMY)
en_US
dc.subject
ZÄHLER UND DETEKTOREN FÜR TEILCHEN UND QUANTEN (KERNPHYSIKALISCHE METHODEN)
en_US
dc.title
Design, construction and first commissioning of the ArDM detector
en_US
dc.type
Doctoral Thesis
dc.rights.license
In Copyright - Non-Commercial Use Permitted
dc.date.published
2013
ethz.size
1 Band
en_US
ethz.code.ddc
DDC - DDC::5 - Science::530 - Physics
en_US
ethz.identifier.diss
20921
en_US
ethz.identifier.nebis
009759662
ethz.publication.place
Zürich
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02010 - Dep. Physik / Dep. of Physics
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02010 - Dep. Physik / Dep. of Physics::02532 - Institut für Teilchen- und Astrophysik / Inst. Particle Physics and Astrophysics::03503 - Rubbia, André / Rubbia, André
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02010 - Dep. Physik / Dep. of Physics::02532 - Institut für Teilchen- und Astrophysik / Inst. Particle Physics and Astrophysics::03503 - Rubbia, André / Rubbia, André
ethz.date.deposited
2017-06-10T13:58:54Z
ethz.source
ECOL
ethz.source
ECIT
ethz.identifier.importid
imp59365057d373d40692
ethz.identifier.importid
imp59366b3b906b165693
ethz.ecolpid
eth:6818
ethz.ecitpid
pub:100658
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2017-07-19T00:58:44Z
ethz.rosetta.lastUpdated
2020-02-15T09:26:39Z
ethz.rosetta.versionExported
true
ethz.COinS
ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.atitle=Design,%20construction%20and%20first%20commissioning%20of%20the%20ArDM%20detector&rft.date=2012&rft.au=Epprecht,%20Lukas&rft.genre=unknown&rft.btitle=Design,%20construction%20and%20first%20commissioning%20of%20the%20ArDM%20detector
 Search print copy at ETH Library

Files in this item

Thumbnail
Thumbnail

Publication type

Show simple item record