Speaker
Description
Neutrinoless double beta decay (0νββ) is an interaction forbidden by the Standard Model because of its lepton-number violating properties. However, if 0νββ was to be observed, the neutrino must be its own anti-particle and the decay would demonstrate lepton number violation. There are several groups searching for this rare decay as it would imply new and exciting physics beyond the Standard Model of particle physics. The nEXO collaboration is one of them and developing a multi-ton scale time-projection chamber. This nEXO detector is anticipated to be sensitive to half-lives on the order of $1\times10^{28}$ years.
A unique advantage of using a Xe time-projection chamber (TPC) detector is the possibility to locate the decay within the detector volume, and to extract into vacuum and identify Ba-136, the ββ-decay daughter of Xe-136. This so-called tagging allows one to dramatically reduce the background of the measurement to virtually zero, except from contributions of the allowed 2νββ. Ba-tagging is being developed as a potential upgrade of the nEXO detector.
The focus of the development is the extraction of individual Ba-ions from xenon, i.e. the extraction of one ion from mols of xenon. This challenging task is being tackled by the development of various techniques within the nEXO collaboration. An in-xenon ion source will be required to characterize the extraction process and efficiency.
To this end, I am virtually working with the Ba-Tagging group at McGill University to develop an In Gas Laser Ablation Source (IGLAS). The goal of this source is to provide ions for test of the Ba-Tagging extraction apparatus for the nEXO experiment upgrade. The source would provide Ba ions for extraction and identification tests. I am working with the group to acquire images of the ion plume using a high speed camera, from vacuum pressure to high-pressure xenon gas. Images will be acquired with a Vimba python program. Code is developed to trigger the camera and start measurements when ablation occurs. The software ImageJ is used to analyze these images and extract dynamical parameters of the ion plume, including plume length, plume angle, and most importantly expansion velocity. These algorithms will be used to better understand the characteristics of the ion plume, and will eventually be used to compute the expansion velocity of the ion plume which is important for the extraction of Ba from the plume. I will present the current status of the work, which includes the algorithms and how to extract the dynamical parameters.
