2 research outputs found
Conceptual design and progress of transmitting MV DC HV into 4 K LHe detectors
A dual-phase TPC (Time Projection Chamber) is more advanced in characterizing
an event than a single-phase one because it can, in principle, reconstruct the
3D (X-Y-Z) image of the event, while a single-phase detector can only show a 2D
(X-Y) picture. As a result, more enriched physics is expected for a dual-phase
detector than a single-phase one. However, to build such a detector, DC HV
(High Voltage) must be delivered into the chamber (to have a static electric
field), which is a challenging task, especially for an LHe detector due to the
extremely low temperature, 4 K, and the very high voltage, MV
(Million Volts). This article introduces a convincing design for transmitting
MV DC into a 4 K LHe detector. We also report the progress of
manufacturing a 100 kV DC feedthrough capable of working at 4 K. Surprisingly,
we realized that the technology we developed here might be a valuable reference
to the scientists and engineers aiming to build residential bases on the Moon
or Mars
Searching for ER and/or NR-like dark matter signals with the especially low background liquid helium TPCs
In the Dark Matter (DM) direct detection community, the absence of convincing
signals has become a ``new normal'' for decades. Among other possibilities, the
``new normal'' might indicate that DM-matter interactions could generate not
only the hypothetical NR (Nuclear Recoil) events but also the ER (Electron
Recoil) ones, which have often been tagged as backgrounds historically.
Further, we argue that ER and NR-like DM signals could co-exist in a DM
detector's same dataset. So in total, there would be three scenarios we can
search for DM signals: (i) ER excess only, (ii) NR excess only, and (iii) ER
and NR excesses combined. To effectively identify any possible DM signal under
the three scenarios, a DM detector should (a) have the minimum ER and NR
backgrounds and (b) be capable of discriminating ER events from NR ones.
Accordingly, we introduce the newly established project, ALETHEIA, which
implements liquid helium-filled TPCs (Time Projection Chamber) in hunting for
DM. Thanks to the nearly single-digit number of ER and NR backgrounds on 1
ton*yr exposure, presumably, the ALETHEIA detectors should be able to identify
any form of DM-induced excess in its ROI (Research Of Interest). As far as we
know, ALETHEIA is the first DM direct detection experiment claiming such an
inclusive search; conventional detectors search DM mainly on the ``ER excess
only'' and/or the ``NR excess only'' channel, not the ``ER and NR excesses
combined'' channel. In addition, we introduce a preliminary scheme to one of
the most challenging R\&D tasks, transmitting 500+ kV into a 4 K LHe detector