Novel resistive charge-multipliers for dual-phase LAr-TPCs: towards stable operation at higher gains

Abstract

Cryogenic versions of Resistive WELL (RWELL) and Resistive Plate WELL (RPWELL) detectors have been developed, aimed at stable avalanche multiplication of ionization electrons in the vapor phase of LAr (dual-phase TPC). In the RWELL, a thin resistive DLC layer deposited on top of an insulator is inserted in between the electron multiplier (THGEM) and the readout anode; in the RPWELL, a resistive ferrite plate is directly coupled to the THGEM. Radiation-induced ionization electrons in the liquid are extracted into the gaseous phase. They drift into the THGEM's holes where they undergo charge multiplication. Embedding resistive materials into the multiplier proved to enhance operation stability due to the mitigation of electrical discharges — thus allowing operation at higher charge gain compared to standard THGEM (a.k.a. LEM) multipliers. We present the detector concepts and report on the main preliminary results.

Development of Fe2O3/YSZ ceramic plates for cryogenic operation of resistive-protected gaseous detectors

“…A measurement at LNT up to comparable charges should be carried out at a later stage, as it can not be confirmed at the moment that the conductivity mechanism is the same across temperatures. It should be noted, however, that for transported-charge densities well in excess of those anticipated by some future experiments (around 100 μC/cm 2 (Leardini et al, 2023)), no effect could be seen at LNT either, for the 70%wt sample (Figure 9-right). This result is encouraging, as the above conditions approach closely those for which detector operation was demonstrated (section 5).…”

“…Hence the charge spectra displayed in Figure 12 correspond to charge-multiplication factors in the range of 10. A more detailed analysis shows that the highest stable gain is 16, about × 3 the values obtained for an unprotected structure (details can be found in (Tesi et al, 2023)).…”

“…Francesc Monrabal Capilla, Donostia International Physics Center (DIPC), Spain applications, operation in ultra-pure noble gas can in principle benefit from a similar protection scheme (Leardini et al, 2023), thus mitigating the impact of the feedback processes that eventually lead to discharge in those conditions.…”

Cryogenic RPWELL: a novel charge-readout element for dual-phase argon TPCs

“…This motivated the development of new materials, in collaboration with the Instituto Galego de Fisica de Altas Enerxias in Santiago de Compostela. A novel ceramic material based on Yttria-Stabilized Zirconia (YSZ) and iron oxide (Fe 2 O 3 ) was engineered for operation at 90 K, -1 - as reported in [29,30]. Compared to [26], the ceramics production, in particular the post-processing stage, has been improved, and the concentration range extended to cover all temperatures of potential interest down to liquid argon (LAr) temperature.…”