AbstractsPhysics

Silicon strip detectors are fast, cost-effective and have an excellent spatial resolution. They are widely used in many high-energy physics experiments. Modern high energy physics experiments impose harsh operation conditions on the detectors, e.g., of LHC experiments. The high radiation doses cause the detectors to eventually fail as a result of excessive radiation damage. This has led to a need to study radiation tolerance using various techniques. At the same time, a need to operate sensors approaching the end their lifetimes has arisen. The goal of this work is to demonstrate that novel detectors can survive the environment that is foreseen for future high-energy physics experiments. To reach this goal, measurement apparatuses are built. The devices are then used to measure the properties of irradiated detectors. The measurement data are analyzed, and conclusions are drawn. Three measurement apparatuses built as a part of this work are described: two telescopes measuring the tracks of the beam of a particle accelerator and one telescope measuring the tracks of cosmic particles. The telescopes comprise layers of reference detectors providing the reference track, slots for the devices under test, the supporting mechanics, electronics, software, and the trigger system. All three devices work. The differences between these devices are discussed. The reconstruction of the reference tracks and analysis of the device under test are presented. Traditionally, silicon detectors have produced a very clear response to the particles being measured. In the case of detectors nearing the end of their lifefimes, this is no longer true. A new method benefitting from the reference tracks to form clusters is presented. The method provides less biased results compared to the traditional analysis, especially when studying the response of heavily irradiated detectors. Means to avoid false results in demonstrating the particle-finding capabilities of a detector are also discussed. The devices and analysis methods are primarily used to study strip detectors made of Magnetic Czochralski silicon. The detectors studied were irradiated to various fluences prior to measurement. The results show that Magnetic Czochralski silicon has a good radiation tolerance and is suitable for future high-energy physics experiments. Väitöstyössä käsitellään paikkaherkkien hiukkasilmaisimien säteilynkestoa sekä kehitetään mittauslaitteita ja -menetelmiä tämän tutkimuksen tarpeisiin. Suuren energian omaava hiukkanen voi saada laitteen toimimaan tilapäisesti väärin tai vaurioittaa sitä pysyvästi esimerkiksi kiderakennetta rikkomalla. Säteilynkestäviä laitteita tarvittiin alun perin avaruustutkimuksessa, mutta nykyään niitä käytetään myös esimerkiksi CERN:ssä sijaitsevan LHC-hiukkastörmäyttimen koeasemissa. Tällä hetkellä keskustellaan LHC-törmäyttimen uudistamisesta nk. Super-LHC:ksi. Uudistuksessa kiihdyttimen luminositeetti eli sen koeasemille toimittama hiukkasvuo kasvatetaan kymmenkertaiseksi. Nykyiset koeasemat eivät kykene toimimaan S-LHC:n…