Physics / Physique - Master's Theses

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Browsing Physics / Physique - Master's Theses by Subject "calibration"

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    Design of a neutron calibration source for the SNO+ experiment
    (2017-11-13) Semenec, Ingrida
    SNO+ is a multipurpose detector situated at the SNOLAB facility located at Creighton mine 2 km deep. The SNO+ experiment will have three phases: water, pure scintillator and Te-loaded scintillator. With the detector filled with scintillator, solar neutrinos, geo and reactor anti-neutrinos, and supernova neutrinos can be studied. To analyze the data collected by the detector, it is important to have detailed knowledge of the detector response. This is why calibration is a crucial part of the experiment. The detector response to neutrons will allow us to study the anti-neutrino flux coming from reactors in Canada. Anti-neutrinos can be detected via the inverse beta decay reaction which can be tagged using the neutrons it produces. This thesis will discuss the radioactive calibration source Americium Beryllium (AmBe) which produces neutrons and gammas. The existing AmBe source - inherited from the SNO experiment - that will be used in water phase has to be modified for the scintillator and loaded scintillator phases. Simulations were carried out to determine the optimal additional shielding required for the scintillator phase. The optimal shielding was determined to be 2 mm of lead surrounded by 1 mm of stainless steel for the encapsulation. The new design for the AmBe source was finalised. The estimated neutron capture event detection efficiency is 74.22%. The analysis of the source deployment at various positions within the detector and the shadowing effects are discussed as well.
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    The SNO+ supernova calibration source development and testing
    (2016-07-19) Darrach, Caitlyn
    SNO+ is a kilotonne-scale, liquid scintillator-based neutrino detector housed in the underground facilities of SNOLAB at Creighton Mine, Sudbury. SNO+ is capable of detecting bursts of neutrinos released by nearby core-collapse supernovae among other physics goals. For such an event, stress testing is required to ensure that a burst of supernova neutrino events can be reliably read out and recorded by the electronics and data acquisition system to avoid data pileup and limit event separation. During a supernova, SNO+ needs to be able to record the burst, send a timely alert to the astronomical community, and quickly analyze and interpret the data. The supernova calibration system (SNC+) for SNO+ simulates the light produced by interactions of neutrinos from a supernova within the liquid scintillator target using pulsed, visible light from a laser diode. The SNC+ is a data-driven pulser capable of producing high-powered, ns-scale pulses with repetition rates up to 12.5 MHz. Each photon pulse is expected to deposit energy of up to 70 MeV within the liquid scintillator of the SNO+ detector. The light from the SNC+ laser diode will be delivered isotropically within the SNO+ detector by ber optics and a di using glass laserball. The SNC+ has undergone design, parts procurement, construction, assembly, and initial-stage testing for this thesis research.