C. Cantini

ArDM: first results from underground commissioning

The Argon Dark Matter experiment is a ton-scale double phase argon Time Projection Chamber designed for direct Dark Matter searches. It combines the detection of scintillation light together with the ionisation charge in order to discriminate the background (electron recoils) from the WIMP signals (nuclear recoils). After a successful operation on surface at CERN, the detector was recently installed in the underground Laboratorio Subterr?neo de Canfranc, and the commissioning phase is ongoing. We describe the status of the installation and present first results from data collected underground with the detector filled with gas argon at room temperature.

Long-term operation of a double phase LAr LEM Time Projection Chamber with a simplified anode and extraction-grid design

We report on the successful operation of a double phase Liquid Argon Large Electron Multiplier Time Projection Chamber (LAr LEM-TPC) equipped with two dimensional projective anodes with dimensions 10

Commissioning of the ArDM experiment at the Canfranc underground laboratory: first steps towards a tonne-scale liquid argon time projection chamber for Dark Matter searches

\times

Performance study of the effective gain of the double phase liquid Argon LEM Time Projection Chamber

10 cm

First test of a high voltage feedthrough for liquid Argon TPCs connected to a 300 kV power supply

^2

Recent R&D results on LAr LEM TPC and plans for LBNO demonstrators

, and with a maximum drift length of 21 cm. The anodes were manufactured for the first time from a single multilayer printed circuit board (PCB). Various layouts of the readout views have been tested and optimised. In addition, the ionisation charge was efficiently extracted from the liquid to the gas phase with a single grid instead of two previously. We studied the response and the gain of the detector to cosmic muon tracks. To study long-term stability over several weeks, we continuously operated the chamber at fixed electric field settings. We reproducibly observe that after an initial decrease with a characteristic time of

Evidence of electric breakdown induced by bubbles in liquid argon

\tau\approx 1.6

Status of the ArDM Experiment: First results from gaseous argon operation in deep underground environment

days, the observed gain is stable. In 46 days of operation, a total of 14.6 million triggers have been collected at a stable effective gain of

Status of ArDM-1t: First observations from operation with a full ton-scale liquid argon target

G_\infty\sim 15

Measurement of the attenuation length of argon scintillation light in the ArDM LAr TPC

corresponding to a signal-to-noise ratio