Abstract
We present in this work measurements performed with a small Micromegas-TPC using a xenon-trimethylamine (Xe-TMA) Penning-mixture as filling gas. Measurements of gas gain and energy resolutions for 22.1 keV X-rays are presented, spanning several TMA concentrations and pressures between 1 and 10 bar. Across this pressure range, the best energy resolution and largest increase in gain at constant field (a standard figure for characterizing Penning-like energy transfers) is observed within the 0.9%–1.7% TMA range. A gain increase (at constant field) up to a factor 100 and best values of the energy resolution improved by up to a factor 3 with respect to the one previously reported in pure Xe -operated Micromegas, can be obtained. In virtue of the VUV-quenching properties of the mixture, the overall maximum gain achievable is also notably increased (up to 400 at 10bar), a factor ×3 higher than in pure Xe. In addition, preliminary measurements of the electron drift velocity in a modified setup have been performed and show good agreement with the one obtained from Magboltz.These results are of great interest for calorimetric applications in gas Xe TPCs, in particular for the search of the neutrino-less double beta decay (0νββ) of 139Xe.It is important to note that in this work some figures from [1] have been updated. Precisely, the TMA concentration has been re-estimated after a detailed re-calibration of the mass spectrometer yielding lower TMA concentration values, corrected by a factor in the range 0.5 – 0.7. An erratum to [1] is being submitted at the moment of writing.
Highlights
The detection of the 0νββ decay in 136Xe can provide both the neutrino mass scale and an unambiguous answer to its nature (Majorana or Dirac)
We have performed systematic measurements of gain and energy resolutions in a small Time Projection Chambers (TPCs) filled with Xe-TMA on a large range of concentrations and pressures
Between 1 and 10 bar, the Penning transfer is optimal for Micromegas operation in the 1.5%2.5% TMA concentration range, allowing to obtain the best energy resolutions and the highest gain increase at constant field
Summary
The detection of the 0νββ decay in 136Xe can provide both the neutrino mass scale and an unambiguous answer to its nature (Majorana or Dirac). For this reason, the development of large gas Xe Time Projection Chambers (TPCs) targeted at finding evidence for 0νββ in 136Xe is currently active. The development of large gas Xe Time Projection Chambers (TPCs) targeted at finding evidence for 0νββ in 136Xe is currently active This kind of detector can fulfill the main requirements of the current generation of experiments (100 kg Xe), which are an energy resolution down to 1% FWHM (full width half maximum) at the excess energy of the decay (Qββ), and topological information from track reconstruction. The microbulk technique [5] has been used in several experiments due to its excellent position resolution and good energy resolution, as well as robustness and low radioactivity [6, 7], being this latter feature more important for rare events searches [8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
