Speaker
Description
The development of radiation detectors has seen significant
advancements over the past decades, particularly in those relying on
electroluminescence. Optical time projection chambers (OTPCs) have
become the preferred choice in the field of direct dark matter
searches (more specifically in WIMP searches), having also been
considered for neutrino experiments. Dark matter experiments examples
include XENON, LZ, DarkSide, and CYGNO where directional information
is expected to be explored. Moreover, these detectors have found
applications in nuclear physics, such as in the study of ββ0ν decay
(NEXT) and 2p-decay and related processes (Warsaw-TPC).
Even though significant progress has been observed in the development
of these detectors since the first works in the 1960s, the
optimization of the light collection efficiency remains an important
concern. Historically, these structures were mostly made up of meshes
or conventional micro-pattern gas detectors (MPGDs) designed for
avalanche mode and working mainly in quenched gases.
Given the expected scalability of most of the aforementioned
detectors, light production and collection pose unique challenges.
Dealing with alignment, and the use of meshes or wires spanning large
areas presents practical limitations. In most cases, relying on
scintillation originated in charge avalanches will affect not only the
energy resolution but also impact the attainable spatial resolution.
In addition, the use of lenses, while enabling the reduction of the
number of optical sensors required to read large areas and improvement
of the optical gain, may limit the spatial resolution attainable,
introducing undesirable optical effects (e.g. aberrations).
Nevertheless, it is important to consider techniques that can mitigate
potential adverse effects associated with the current amplification
structures and readout.
In this work, the challenges for improving the light collection as
well as the minimization of the background in dual-phase TPCs
resulting from spurious emission will be discussed. We will start with
a brief overview of the evolution of electroluminescence studies,
along with strategies to address some of the main challenges faced in
the development of such detectors for Dark matter searches.
Alternative structures, GEM-based, capable of providing higher optical
gains without relying on avalanche multiplication, thus enhancing
energy resolution and detector stability (while eliminating ion
back-flow), will be presented.
