Thick GEM-like hole multipliers: properties and possible applications

The properties of thick GEM-like (TGEM) gaseous electron multipliers, operated at 1-740 Torr are presented. They are made of a G-10 plate, perforated with millimeter-scale diameter holes. In single-multiplier elements, effective gains of about 104, 106, and 105 were reached at respective pressures of 1, 10 Torr isobutane and 740 Torr Ar/5%CH4, with pulse rise-times in the few nanosecond scale. The high effective gain at atmospheric pressure was measured with a TGEM coated with a CsI photocathode. The detector was operated in single and cascaded modes. Potential applications in ion and photon detection are discussed.Comment: Contribution to the 2004 Vienna Conference on Instrumentatio

CsI-THGEM gaseous photomultipliers for RICH and noble-liquid detectors

The properties of UV-photon imaging detectors consisting of CsI-coated THGEM electron multipliers are summarized. New results related to detection of Cherenkov light (RICH) and scintillation photons in noble liquid are presented.Comment: 5 Pages, 10 Figures; Presented at the 7th International Workshop on Ring Imaging Cherenkov Detectors (RICH 2010) RICH2010 - Cassis, Provence, France, 3-7 May 201

Performance test of a micro-pattern stereo detector with two gas electron multipliers [online]

We report on the performance of a large micro-pattern detector with two gas electron multiplier foils (GEM) and a two-layer readout structure at ground potential. The two readout layers each have a 406 micro-m pitch and cross at an effective angle of 6.7 degrees. This structure allows for two orthogonal coordinates to be determined. Using a muon beam at CERN together with a silicon tracking system, the position resolutions of the two coordinates are measured to be 50 micro-m and 1 mm respectively (1 stand.dev.). The muon detection efficiency for the two-dimensional space points reaches 96%. The detector was found to be well operational over a wide range in the settings of the different electrical fields

Construction and performance of a micro-pattern stereo detector with two gas electron multipliers [online]

The construction of a micro-pattern gas detector of dimensions 40 x 10 cm² is described. Two gas electron multiplier foils (GEM) provide the internal amplification stages. A two-layer readout structure was used, manufactured in the same technology as the GEM foils. The strips of each layer cross at an effective crossing angle of 6.7 degrees and have a 406 micro-m pitch. The performance of the detector has been evaluated in a muon beam at CERN using a silicon telescope as reference system. The position resolutions of two orthogonal coordinates are measured to be 50 micro-m and 1 mm, respectively. The muon detection efficiency for two-dimensional space points reaches 96%. Key words: detector, position sensitive, GEM, two-layer readou

12 year Northern Borneo cave drip water oxygen isotopic time series

We present ~twelve year-long time series of biweekly cave drip water (oxygen isotope) variations from three sites from Gunung Mulu National Park in Northern Sarawak, Borneo. Lastly, seven spatial surveys of stalagmite and non-stalagmite forming cave drip water (oxygen isotopes) were taken in: August 2008 (N = 63), Feb/Mar, 2010 (N = 128), Oct/Nov 2012 (N = 291), Feb/Mar 2013 (N = 37), May, 2016 (N = 92), May, 2017 (N = 180), and Mar/Apr, 2018 (N = 124). Twelve years of monitoring data presented in this study identify individual El Niño-Southern Oscillation (ENSO) events in rainfall and cave drip water isotopic composition, providing a robust interpretive framework for past and future stalagmite isotope records from this site