Test of a Liquid Argon TPC in a magnetic field and investigation of high temperature superconductors in liquid argon and nitrogen

Tests with cosmic ray muons of a small liquid argon time projection chamber (LAr TPC) in a magnetic field of 0.55 T are described. No effect of the magnetic field on the imaging properties were observed. In view of a future large, magnetized LAr TPC, we investigated the possibility to operate a high temperature superconducting (HTS) solenoid directly in the LAr of the detector. The critical current $I_c$ of HTS cables in an external magnetic field was measured at liquid nitrogen and liquid argon temperatures and a small prototype HTS solenoid was built and tested.Comment: 5 pages, 5 figures, to appear in Proc. of 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba (Japan), March 201

First operation of a liquid Argon TPC embedded in a magnetic field

We have operated for the first time a liquid Argon TPC immersed in a magnetic field up to 0.55 T. We show that the imaging properties of the detector are not affected by the presence of the magnetic field. The magnetic bending of the ionizing particle allows to discriminate their charge and estimate their momentum. These figures were up to now not accessible in the non-magnetized liquid Argon TPC.Comment: 9 pages, 3 figure

Feasibility of high-voltage systems for a very long drift in liquid argon TPCs

Designs of high-voltage (HV) systems for creating a drift electric field in liquid argon TPCs are reviewed. In ongoing experiments systems capable of approx. 100 kV are realised for a drift field of 0.5-1 kV/cm over a length of up to 1.5 m. Two of them having different approaches are presented: (1) the ICARUS-T600 detector having a system consisting of an external power supply, HV feedthroughs and resistive voltage degraders and (2) the ArDM-1t detector having a cryogenic Greinacher HV multiplier inside the liquid argon volume. For a giant scale liquid argon TPC, a system providing 2 MV may be required to attain a drift length of approx. 20 m. Feasibility of such a system is evaluated by extrapolating the existing designs.Comment: 8 pages, 13 figures, to appear in Proc. of 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba (Japan), March 201

High-Temperature Superconducting Level Meter for Liquid Argon Detectors

Capacitive devices are customarily used as probes to measure the level of noble liquids in detectors operated for neutrino studies and dark matter searches. In this work we describe the use of a high-temperature superconducting material as an alternative to control the level of a cryogenic noble liquid. Lab measurements indicate that the superconductor shows a linear behaviour, a high degree of stability and offers a very accurate determination of the liquid volume. This device is therefore a competitive instrument and shows several advantages over conventional level meters.Comment: 13 pages, 11 figures. Accepted for publication in JINS

Social differentiation and well‑being in the Italian Iron Age: exploring the relationship between sex, age, biological stress, and burial complexity among the Picenes of Novilara (8th–7th c. BC)

The restoration of the archaeological finds from Novilara was performed in the frame of the "Progetto di restauro degli oggetti di corredo rinvenuti nella necropoli picena di Novilara" (Swiss Federal Office of Culture) and with the additional financial support of Fondazione Scavolini (Italy).The possible association between “biological” and “social” status in the past is a central topic in bioarchaeological studies. For the Italian Iron Age, previous research comparing skeletal and funerary variables depicts a multifaceted scenario consistent with nuanced biocultural patterns. This calls for additional studies on a broader series of archaeological contexts and skeletal assemblages. Here, we contribute new data about the biological correlates of social differentiation during the Italian Iron Age by comparing paleopathological and funerary variables in the Picene necropolis of Novilara (Marche region, 8th–7th c. BC). Novilara is one of the largest Picene necropolises in the Italian Peninsula and one of the most important funerary sites of the Italian Iron Age. The skeletal sample includes 147 individuals (females: 70; males: 35; 10 unsexed adults; 32 non-adults). We use linear enamel hypoplasia, cribra orbitalia, porotic hyperostosis, non-specific periosteal lesions, and stature to approximate non-specific stressors and compare them with archaeological variables summarizing funerary variability by means of logistic models, Mann–Whitney and Spearman tests. Results are heterogeneous and vary according to the considered variables. On average, they however show that (a) adults featuring a more complex funerary treatment have a lower probability of showing stress-related skeletal changes, and (b) even though funerary features suggests a strong gender differentiation, frequencies of paleopathological variables do not differ between sexes. Our analyses point to a complex link between biological and social status in this population and call for a critical reflection about the theoretical and methodological issues affecting similar studies.Fondazione Scavolini (Italy

First results from a Liquid Argon Time Projection Chamber in a Magnetic Field

A small liquid argon Time Projection Chamber (LAr TPC) was operated for the first time in a magnetic field of 0.55 Tesla. The imaging properties of the detector were not affected by the magnetic field. In a test run with cosmic rays a sample of through going and stopping muons was collected. The chamber with the readout electronics and the experimental setup are described. A few selected events were reconstructed and analyzed and the results are presented. The magnetic bending of the charged particle tracks allows the determination of the electric charge and the momentum, even for particles not fully contained in the drift chamber. These features are e.g. required for future neutrino detectors at a neutrino factory.Comment: 35 pages, 25 figures, version with full resolution figures at available at http://neutrino.ethz.ch/GLACIER