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A comprehensive R&D program on LAr Time Projection Chambers (LAr TPC) is presently being carried out at the University of Bern. Many aspects of this technology are under investigation: HV, purity, calibration, readout, etc. Furthermore, multi-photon interaction of UV-laser beams with LAr has successfully been measured. Possible applications of the LAr TPC technology in the field of homeland security are also being studied. In this paper, the main aspects of the program will be reviewed and the achievements underlined. Emphasis will be given to the largest device in Bern, i.e. the 5 m long ARGONTUBE TPC, meant to prove the feasibility of very long drifts in view of future large scale applications of the technique.

Radiation hardness up to 10 16 n eq /cm 2 is required in the future HEP experiments for most inner detectors. However, 10 16 n eq /cm 2 fluence is well beyond the radiation tolerance of even the most advanced semiconductor detectors fabricated by commonly adopted technologies: the carrier trapping will limit the charge collection depth to an effective range of 20–30 μm regardless of depletion depth. Significant improvement of the radiation hardness of silicon sensors has been taken place within RD39. Fortunately the cryogenic tool we have been using provides us a convenient way to solve the detector charge collection efficiency (CCE) problem at SLHC radiation level (10 16 n eq /cm 2 ). There are two key approaches in our efforts: (1) use of the charge/current injection to manipulate the detector internal electric field in such a way that it can be depleted at a modest bias voltage at cryogenic temperature range (⩽230 K); and (2) freezing out of the trapping centers that affects the CCE at cryogenic temperatures lower than that of the LN 2 temperature. In our first approach, we have developed the advanced radiation hard detectors using charge or current injection, the current injected diodes (CID). In a CID, the electric field is controlled by injected current, which is limited by the space charge, yielding a nearly uniform electric field in the detector, independent of the radiation fluence. In our second approach, we have developed models of radiation-induced trapping levels and the physics of their freezing out at cryogenic temperatures. In this approach, we intend to study the trapping effect at temperatures below LN 2 temperature. A freeze-out of trapping can certainly help in the development of ultra-radiation hard Si detectors for SLHC. A detector CCE measurement system using ultra-fast picosecond laser with a He cryostat has been built at CERN. This system can be used to find out the practical cryogenic temperature range that can be used to freeze out the radiation-induced trapping levels, and it is ready for measurements on extremely heavily irradiated silicon detectors. Initial data from this system will be presented.

There are two key approaches in our CERN RD 39 Collaboration efforts to obtain ultra-radiation-hard Si detectors: (1) use of the charge/current injection to manipulate the detector internal electric field in such a way that it can be depleted at a modest bias voltage at cryogenic temperature range (⩽150 K), and (2) freezing out of the trapping centers that affects the CCE at cryogenic temperatures lower than that of the liquid nitrogen (LN 2 ) temperature. In our first approach, we have developed the advanced radiation hard detectors using charge or current injection, the current injected diodes (CID). In a CID, the electric field is controlled by injected current, which is limited by the space charge, yielding a nearly uniform electric field in the detector, independent of the radiation fluence. In our second approach, we have developed models of radiation-induced trapping levels and the physics of their freezing out at cryogenic temperatures.

In this paper we report on the design, construction, and operation of a cryogenic system designed to cool a Superheated Superconducting Granule (SSG) detector for dark matter search. The volume accommodating SSG detector is 20 cm in diameter and 67 cm long. The system provides a lowest operating temperature of 115 mK for long-lasting (several months) experiments in the Bern Underground Laboratory.

The ORPHEUS dark matter detector consists of 450 g superconducting tin granules with diameters of 28 and 36 μm . The detector has been operating in the shallow site of the underground laboratory in Bern ( 70 m . w . e ). First preliminary results on WIMP detection sensitivity will be presented.

RD39 collaboration develops new detector techniques for particle trackers, which have to withstand fluences up to 10 16 cm −2 of high-energy particles. The work focuses on the optimization of silicon detectors and their readout electronics while keeping the temperature as a free parameter. Our results so far suggest that the best operating temperature is around 130 K . We shall also describe in this paper how the current-injected mode of operation reduces the polarization of the bulk silicon at low temperatures, and how the engineering and materials problems related with vacuum and low temperature can be solved.

The CERN RD39 Collaboration studies the possibility to extend the detector lifetime in a hostile radiation environment by operating them at low temperatures. The outstanding illustration is the Lazarus effect, which showed a broad operational temperature range around 130 K for neutron irradiated silicon detectors.

We present a study of the modeling of the electric field distribution, which is controlled by injection and trapping of nonequilibrium carriers, in Si detectors irradiated by high neutron fluences. An analytical calculation of the electric field distribution in detectors irradiated by neutrons up to fluences of 1 /spl middot/ 10/sup 14/ to 5 /spl middot/ 10/sup 15/ cm/sup -2/ shows the possibility of reducing the full depletion voltage at low temperatures via hole injection. For this calculation, we use the detector operating parameters and equivalent neutron fluences expected for Large Hadron Collider experiments. The results of the calculation are in good qualitative agreement with published experimental data, lending strong support for the model and for an earlier proposal of electric field manipulation by free carrier injection.

Though several studies have proved the radiation tolerance of silicon detectors at cryogenic temperatures, following room temperature irradiation, no previous investigation has studied the behaviour of detectors irradiated ‘‘in situ’’ at low temperatures. In this work, effects of irradiation of 450 GeV protons at 83 K will be presented, showing that after a dose of 1.2 � 10 15 pc m � 2 a charge collection efficiency (CCE) of 55% is reached at 200 V before the annealing. The same results were found at the end of the irradiation, after the sample has spent more then one year at room temperature. This shows that the CCE recovery by low temperature operation is not affected by the temperature of irradiation and by the reverse annealing. r 2002 Elsevier Science B.V. All rights reserved.

It has been recently observed that heavily irradiated silicon detectors, no longer functional at room temperature, "resuscitate" when operated at temperatures below 130 K. This is often referred to as the "Lazarus effect". The results presented here show that cryogenic operation represents a new and reliable solution to the problem of radiation tolerance of silicon detectors.

ARGONTUBE is a liquid argon time projection chamber (LAr TPC) with a drift field generated in-situ by a Greinacher voltage multiplier circuit. We present results on the measurement of the drift-field distribution inside ARGONTUBE using straight ionization tracks generated by an intense UV laser beam. Our analysis is based on a simplified model of the charging of a multi-stage Greinacher circuit to describe the voltages on the field cage rings.

We present a method to reach electric field intensity as high as 400 kV/cm in liquid argon for cathode-ground distances of several millimeters. This can be achieved by suppressing field emission from the cathode, overcoming limitations that we reported earlier.

ARGONTUBE is a liquid argon time projection chamber (TPC) with an electron drift length of up to 5 m equipped with cryogenic charge-sensitive preamplifiers. In this work, we present results on its performance, including a comparison of the new cryogenic charge-sensitive preamplifiers with the previously used room-temperature-operated charge preamplifiers.

In this paper, we report on the performance of heavily irradiated silicon detectors operated at cryogenic temperatures. The results discussed here show that cryogenic operation indeed represents a reliable method to increase the radiation tolerance of standard silicon detectors by more than one order of magnitude. In particular, a 400 μm thick “double-p” silicon detector irradiated up to 1×10 15 n/cm 2 delivers a mip signal of about 27 000 electrons when operated at 130 K and 500 V bias. The position resolution of an irradiated microstrip detector, and “in situ” irradiation of a pad detector during operation in the cold are also discussed.

We present results on the measurement of the charge collection efficiency of a p + /n/p + silicon detector irradiated to 1×10 15 n/cm 2 , operated in the temperature range between 80 and 200 K. For comparison, measurements obtained with a standard silicon diode (p + /n/n + ), irradiated to the same fluence, are also presented. Both detectors show a dramatic increase of the CCE when operated at temperatures around 130 K. The double-p detector shows a higher CCE regardless of the applied bias and temperature, besides being symmetric with respect to the polarity of the bias voltage. At 130 K and 500 V applied bias the double-p detector shows a CCE of 80%, an unprecedented result for a silicon detector irradiated to such a high dose.

We have investigated the superheating and the supercooling fields of a planar array of tin cylinders with diameters ranging from 40 to 80 μm and thickness 8.3 μm evaporated onto a glass substrate and onto a kapton foil. Experimental values of the Ginzburg–Landau parameter have been obtained and compared with results from tin spheres. The spread of the superheating curves is below 5%.

This paper reports on measurements at cryogenic temperatures of a silicon microstrip detector irradiated with 24 GeV protons to a #uence of 3.5]1014 p/cm2 and of a p}n junction diode detector irradiated to a similar #uence. At temperatures below 130 K a recovery of charge collection e$ciency and resolution is observed. Under reverse bias conditions this recovery degrades in time towards some saturated value. The recovery is interpreted qualitatively as

A considerably improved phase transition homogeneity was observed with superheated superconducting Sn spheres as a result of laser melting and fast cooling. These spheres exhibited a very homogeneous phase transition behaviour independent of the orientation of the spheres with respect to the direction of the external magnetic field. Compared to previously untreated Sn spheres the spread of the phase transition boundaries was reduced by almost an order of magnitude. In addition, we studied mass production of Sn structures using vacuum evaporation and deposition. First encouraging results are reported.

An increasing interest in the behaviour of silicon detectors at cryogenic temperatures has been awakened by the discovery of the so-called Lazarus effect, namely the recovery of charge collection efficiency (CCE) by means of cryogenic cooling. We measured the CCEs of three single diodes previously irradiated with different neutron fluences. The current-voltage characteristic were measured at 300 and 77 K, showing that the low-temperature operation considerably decreases the steady-state current. This is also the case when a forward voltage bias is applied, which then becomes a suitable option. At 77 K, in the case of samples irradiated with 5 x 10 14 neutrons cm -2 , the CCE is completely recovered. A third sample irradiated with 2 x 10 15 neutrons cm -2 shows a 60% CCE at 250V forward bias.

This paper presents results on the measurement of the cluster shapes, resolution and charge collection efficiency of a double-sided silicon microstrip detector after irradiation with 24 GeV protons to a fluence of 3.5×10 14 p/cm 2 and operated at cryogenic temperatures. An empirical model is presented which describes the expected cluster shapes as a function of depletion depth, and is shown to agree with the data. It is observed that the clusters on the p-side broaden if the detector is under-depleted, leading to a degradation of resolution and efficiency. The model is used to make predictions for detector types envisaged for the LHC experiments. The results also show that at cryogenic temperature the charge collection efficiency varies depending on the operating conditions of the detector and can reach values of 100% at unexpectedly low bias voltage. By analysing the cluster shapes it is shown that these variations are due to changes in depletion depth. This phenomenon, known as the “Lazarus effect”, can be related to similar recent observations on diode behaviour.

The charge collection efficiency (CCE) of heavily irradiated silicon diode detectors was investigated at temperatures between 77 and 200 K. The CCE was found to depend on the radiation dose, bias voltage value and history, temperature, and bias current generated by light. The detector irradiated to the highest fluence 2×10 15 n/cm 2 yields a MIP signal of at least 15000 e − both at 250 V forward bias voltage, and at 250 V reverse bias voltage in the presence of a light-generated current. The “Lazarus effect” was thus shown to extend to fluences at least ten times higher than was previously studied.

In this work we show that a heavily irradiated double-sided silicon microstrip detector recovers its performance when operated at cryogenic temperatures. A DELPHI microstrip detector, irradiated to a fluence of /spl sim/4/spl times/10/sup 14/ p/cm/sup 2/, no longer operational at room temperature, cannot be distinguished from a non-irradiated one when operated at T

We demonstrate the hybrid superconducting pixel detector (HSPD) principle using a test configuration. This device consists of a Si detector bonded by ultra-thin Al wires to a high quality Nb/AlOx/Nb Josephson Tunnel Junction acting as current sensitive discriminator. Experimental data, obtained with a 106 Ru beta source, clearly show minimum ionising particle (mip) detection capability. The efficiency of the tested device reaches 90% with signals corresponding to 2 mips and it can be significantly improved once the complete device is monolithically integrated in one circuit.

One of the limitations of the ORPHEUS dark matter detector performances was the phase transition smearing of the spherical granules. This could be dramatically improved by the use of cylindrical tin arrays. Results of measurements with prototypes are shown.

The ORPHEUS dark matter detector consists of 450 g superconducting tin granules with diameters of 28 μm and 36 μm. The detector has been operating in the shallow site of the underground laboratory in Bern (70 m.w.e). Preliminary results on WIMP detection sensitivity are presented.

We report on the design, construction, and operation of a PID temperature controlled and vacuum tight camera casing. The camera casing contains a commercial digital camera and a lighting system. The design of the camera casing and its components are discussed in detail. Pictures taken by this cryo-camera while immersed in argon vapour and liquid nitrogen are presented. The cryo-camera can provide a live view inside cryogenic set-ups and allows to record video.

The Liquid Argon Time Projection Chamber (LArTPC) is a prime type of detector for future large-mass neutrino observatories and proton decay searches. In this paper we present the design and operation, as well as experimental results from ARGONTUBE, a LArTPC being operated at the AEC-LHEP, University of Bern. The main goal of this detector is to prove the feasibility of charge drift over very long distances in liquid argon. Many other aspects of the LArTPC technology are also investigated, such as a voltage multiplier to generate high voltage in liquid argon (Greinacher circuit), a cryogenic purification system and the application of multi-photon ionization of liquid argon by a UV laser. For the first time, tracks induced by cosmic muons and UVlaser beam pulses have been observed and studied at drift distances of up to 5 m, the longest reached to date.

More than 170 pecan (Carya illinoensis (Wangenh.) K. Koch) cultivars were evaluated formalate dehydrogenase, phosphoglucose isomerase, phosphoglucomutase, leucine aminopeptidase (LAP), and diaphorase (DIA). Isozymes of LAP were observed in two regions after starch gel electrophoresis. The faster region of activity (Lap-1) was polymorphic and consistently expressed in leaves, wood, and roots. Controlled crosses suggest that Lap-1 is simply inherited and controlled by at least two alleles. DIA was well resolved and storable only from leaf material and produced a complex banding pattern. The ability to differentiate among cultivars by isozymes was good. The 177 cultivars sorted into 72 classes. Forty of the cultivars (23% ) possessed a unique series of isozyme patterns. Most cultivars (124 of 177) shared common banding patterns with less than four other cultivars. From the inheritance models of four isozymes, some historical pedigrees can be questioned. Most notably,' Western Schley' could not have been parented by 'San Saba' based on the inheritance of Mdh-1 and Lap-1. Isozyme analysis by gel electrophoresis can help validate plant pedigrees, phylogeny, ploidy, and mating systems and help distin- guish among named cultivars (Peirce and Brewbaker, 1973). Isozymes typically are simply inherited and largely unaffected by the environment. Pecan is presumed to be a heterogeneous species based on the relatively large native range (Little, 1971; Thompson and Grauke, 1990), observed variability of isozymes, and morpho- logical variability. About 1000 cultivars have been named since the mid- 1800s (Thompson and Young, 1985). Pecan breeding by U.S. Dept. of Agriculture (USDA) scientist's began in the 1930s. Most pecan cultivars are wild selections, or have pedigrees that are incomplete or limited to one or two generations.

This work is part of an ongoing project to develop a Superheated Superconducting Granule (SSG) detector for cold dark matter and neutrinos. The response of SSG devices to nuclear recoils has been explored irradiating SSG detectors with a 70MeV neutron beam. The aim of the experiment was to test the sensitivity of Sn, Al and Zn SSG detectors to nuclear recoil energies down to a few keV. The detector consisted of a hollow teflon cylinder (0.1cm$^3$ inner volume) filled with tiny superconducting metastable granules embedded in a dielectric medium. The nuclear recoil energies deposited in the SSG were determined measuring the neutron scattering angles with a neutron hodoscope. Coincidences in time between the SSG and the hodoscope signals have been clearly established. In this paper the results of the neutron irradiation experiments at different SSG intrinsic thresholds are discussed and compared to Monte Carlo simulations. The results show that SSG are sensitive to recoil energies down to $\sim$1keV. The limited angular resolution of the neutron hodoscope prevented us from measuring the SSG sensitivity to even lower recoil energies., 14 pages in pure LaTeX, 17 figures available on request from schmiemann@lhep.unibe.ch, submitted to Phys. Rev. D, August 1994

We present a study on the dependence of electric breakdown discharge properties on electrode geometry and the breakdown field in liquid argon near its boiling point. The measurements were performed with a spherical cathode and a planar anode at distances ranging from 0.1 mm to 10.0 mm. A detailed study of the time evolution of the breakdown volt-ampere characteristics was performed for the first time. It revealed a slow streamer development phase in the discharge. The results of a spectroscopic study of the visible light emission of the breakdowns complement the measurements. The light emission from the initial phase of the discharge is attributed to electro-luminescence of liquid argon following a current of drifting electrons. These results contribute to set benchmarks for breakdown-safe design of ionization detectors, such as Liquid Argon Time Projection Chambers (LAr TPC)., Comment: Minor revision according to editor report. 17 pages, 15 figures, 2 tables. Turboencabulator

The response of Superheated Superconducting Granule (SSG) devices to nuclear recoils has been explored by irradiating SSG detectors with a 70Me$\!$V neutron beam. In the past we have tested Al SSG and more recently, measurements have been performed with Sn and Zn detectors. The aim of the experiments was to test the sensitivity of SSG detectors to recoil energies down to a few ke$\!$V. In this paper, the preliminary results of the neutron irradiation of a SSG detector made of Sn granules 15-20$\mu$m in diameter will be discussed. For the first time, recoil energy thresholds of $\sim$1ke$\!$V have been measured.

We investigated the phase transition time of single Sn, In and Al granules from 20 μm up to 50 μm in diameter. The transitions from the superconducting to the normal state were induced by ramping the external magnetic field above the superheating field or by irradiating the granules with X-ray or β sources at a constant magnetic field. The readout electronics was optimized to allow real-time measurements with a signal resolution of 11 ns. Within the experimental errors, the irradiation measurements revealed no difference between magnetically and thermally induced phase transitions. The dependence of the transition time on the temperature, the granule size and the orientation of the sample with respect to the magnetic field is discussed. The presented results are part of an ongoing project to develop a Superheated Superconducting Granule (SSG) detector for cold dark matter search and neutrino detection.

The ORPHEUS dark matter experiment is completed at our shallow depth laboratory in Bern (70 m.w.e.). The detector relies on measuring the magnetic flux variation produced by weakly interacting massive particles (WIMPs) as they heat 30 μm diameter superheated superconducting tin granules (SSG) and induce superconducting-to-normal phase transitions. In an initial phase, 0.45 kg of tin granules in a segmented detector volume have been used. Preliminary results of the experiment will be reported.

The response of Superheated Superconducting Granule (SSG) devices to nuclear recoils has been explored by irradiating SSG detectors with a 70MeV neutron beam. In the past we have tested Al SSG and more recently, measurements have been performed with Sn and Zn detectors. The aim of the experiments was to test the sensitivity of SSG detectors to recoil energies down to a few keV. In this paper, the preliminary results of the neutron irradiation of a SSG detector made of Sn granules 15–20µm in diameter will be discussed. For the first time, recoil energy thresholds of ∼1keV have been measured.

The presented results are part of a feasibility study of a Superheated Superconducting Granule (SSG) device for weakly interacting massive particles (WIMPs) detection. The sensitivity of SSG to nuclear recoils has been explored irradiating SSG detectors with a 70MeV neutron beam proving that energy thresholds of ∼1keV can be reached in 30µm Zn and 17µm Sn granules. The successful irradiation experiments with neutrons encouraged us to plan a prototype SSG dark matter detector. The status of the project will be presented and the expected counting rate for spin-independent WIMP interactions in SSG detectors will be discussed.

The presented results are part of a feasibility study of superheated superconducting microstructure detectors. The microstructures (dots) were fabricated using thin film patterning techniques with diameters ranging from $50\mu$m up to $500\mu$m and thickness of $1\mu$m. We used arrays and single dots to study the dynamics of the superheating and supercooling phase transitions in a magnetic field parallel to the dot surface. The phase transi- tions were produced by either varying the applied magnetic field strength at a constant temperature or changing the bath temperature at a constant field. Preliminary results on the dynamics of the phase transitions of arrays and single indium dots will be reported., Comment: 7pages in LaTex format, five figures available upon request by schmiemann@lhep.unibe.ch, preprint Bu-He 93/5

We present results of an irradiation of a Superheated Superconducting Granule (SSG) detector with a 70 MeV neutron beam. The aim of the experiment was to measure the sensitivity of the detector to nuclear recoil energies produced by elastically scattered neutrons. The detector consists of a small readout coil (diameter 5 mm, length 10 mm) filled with aluminum granules of average diameter 23 μm embedded in an Al2O3 granulate with a 6% volume filling factor. The neutron scattering angles were determined using a scintillator hodoscope. Coincidences in time between the SSG and the hodoscope signals have been clearly established. Data were taken at an operating temperature of 120 mK for different SSG intrinsic thresholds. The results prove the sensitivity of the detector to nuclear recoils in the energy range of a few keV. The data show good agreement with the global heating mechanism.

A low-mass cryogenic cooling technique for silicon sensor modules has been developed in the framework of the RD39 Collaboration at CERN. A prototype low-mass beam tracker cryostat has been designed, constructed and tested for applications in fixed target experiments. We shall report here briefly the main features and results of the system.

In this paper we describe the technology of building a vacuum-tight high voltage feedthrough which is able to operate at voltages up to 30 kV. The feedthrough has a coaxial structure with a grounded sheath which makes it capable to lead high voltage potentials into cryogenic liquids, without risk of surface discharges in the gas phase above the liquid level. The feedthrough is designed to be used in ionization detectors, based on liquefied noble gases, such as Argon or Xenon.

In this paper we report on a detailed study of ionization signals produced by Compton electrons and alpha-particles in a Time Projection Chamber (TPC) flled with different mixtures of liquid Argon and Nitrogen. The measurements were carried out with Nitrogen concentrations up to 15% and a drift electric feld in the range 0-50 kV/cm. A prediction for proton ionization signals is made by means of interpolation. This study has been conducted in view of the possible use of liquid Ar-N2 TPCs for the detection of gamma-rays in the resonant band of the Nitrogen absorption spectrum, a promising technology for security and medical applications.

The discovery of the so-called Lazarus e!ect, namely the recovery of the charge collection e$ciency (CCE) of irradiated silicon detectors by means of cryogenic cooling has entailed an increasing interest in the behavior of silicon detectors at cryogenic temperatures. We have measured the CCE of a silicon p}i}n diode detector previously irradiated with an equivalent #uence of 1]1015 n/cm2 neutrons of 1 MeV energy. The charge collection e$ciency has been measured at 77 K, showing that the low-temperature operation considerably decreases the bias current. This is also the case when forward voltage bias is applied, which then becomes a suitable option. In this condition, the sample shows a charge collection e$ciency in excess of 65% at 250 V corresponding to a most probable signal for a minimum ionizing particle of 21 000e~. ( 2000 Elsevier Science B.V. All rights reserved.

This paper describes the design, realization and operation of a prototype liquid Argon Time Projection Chamber (LAr TPC) detector dedicated to the development of a novel online monitoring and calibration system exploiting UV laser beams. In particular, the system is intended to measure the lifetime of the primary ionization in LAr, in turn related to the LAr purity level. This technique could be exploited by present and next generation large mass LAr TPCs for which monitoring of the performance and calibration plays an important role. Results from the first measurements are presented together with some considerations and outlook., 26 pages, 27 figures

Recent research in BCI focuses not only on developing a new communication channel for severely handicapped people but also on applications for rehabilitation, multimedia, communication, virtual reality, entertainment and relaxation. Most of them fall in the domain of human-computer interfaces (HCIs) designed for interaction between brain, eyes, body and computer or robot. For brain signal acquisition several technologies have been applied, for example electroencephalography (EEG), magneto encephalography (MEG), functional magnetic resonance imaging (fMRI) and near infrared spectroscopy (NIRS). Portability and cost effectiveness problems channeled BCI systems to exploit EEG signals mostly. This paper presents a methodology and recommended parameter setting, for representation in time-frequency scale of EEG signals. It refines the detection of event-related changes in the signals, revealing specific patterns of rhythms, for actual and intended physical movement. The result shows that, with well defined window length it is possible to improve localization of specific frequencies within the brain activity. This lead to the fact that actual muscle activity form could be identified from EEG signals. Using the referenced methodology a wide range of HCIs systems can be designed to perform specific tasks for the benefit of the end-user.

This article describes the realization of such an online Web shop which can be integrated subsequently into any field of online sales. This specific example for the use of this application presents an online Web shop for computer hardware and software. The aim of this task is to create an application which the administrator can update and maintain on his or her own without the intervention of a programmer. For this reason it is important to make a suitably formed administrative page with all necessary operations which provide a user-friendly environment. A vital factor during the design phase is that the administrator does not need to have programming knowledge to be able to use this application.

In modern robotics path finding is usually done by storing 3D models of objects into robots memory so the robot can compare the object in front of the camera with the model in its memory while it is trying to navigate between obstacles. With this approach we need 3D model of every object the robot may come into contact with, which is possible only if we confine the robot to a known environment. This paper proposes that path finding for mobile robots be based on 3D extraction of a 2D image edge detection and infrared (IR) distance measuring sensor.

In this paper we report on the evidence for ionization track signals from cosmic ray muons and Compton electrons in a Time Projection Chamber (TPC) filled with liquid Argon and doped with different fractions of Nitrogen. This study has been conducted in view of the possible use of liquid Argon/Nitrogen TPCs for the detection of gamma rays in the resonant band of the Nitrogen absorbtion spectrum, a promising technology for security and medical applications., v2: minor content change and picture improvements

There is a significant and progressive change in the IR spectra associated with H2O hydrogen bonding in alkali metal hydroxide monohydrates as cation size increases from Li+ to Cs+. Lithium and sodium hydroxide monohydrates show IR bands typical of normal electrostatic hydrogen bonds; in contrast, the IR spectra of cesium and rubidium hydroxide monohydrates resemble that of potassium dihydrogen trifluoride, and suggest that covalent three-center hydrogen bonds might be present. The spectrum of potassium hydroxide monohydrate shows both types of absorptions. The IR spectra are not in accord with diffraction studies, which support the presence of electrostatic hydrogen bonds in all of these hydrates. Equilibrium dissociation vapor pressure measurements show that the hydrogen bonds in sodium hydroxide monohydrate have a minimum strength of ∼ 15 kcal mol−1, twice as great as those in lithium hydroxide monohydrate. The physical properties of the higher alkali metal monohydrates demonstrate that water is extraordinarily tightly bound in these compounds.

All of the state-of-the-art systems are statistical data-driven systems that rely on training to model our ignorance about speech which result in enormous memory and processor consumption. Those solutions can not be easily integrated in embedded systems like e.g. as interface for human-robotic interaction. In this paper, an isolated word recognition system has been developed for communication with mobile robot. Presented algorithm is based on phoneme recognition by identifying characteristics of each phoneme which means that it's not based on statistical ASR (not based on HMM-hidden Markov model or ANN-artificial neural network). Final goal of this project is developing a speaker and language independent phoneme recognition platform for use in embedded systems with low power and memory consumption.

A progress report of the ORPHEUS dark matter experiment in the Bern Underground Laboratory is presented. A description of the ORPHEUS detector and its sensitivity to WIMPs is given. The detector will consist of 1 to 2 kg Sn granules operating in a magnetic field of approximately 320 G and at a temperature of 50 mK. In the first phase, the detector will be read out by conventional pickup coils, followed by a second phase with SQUID loops. Preliminary results on background and radioactivity measurements are shown.