Measurements on a prototype segmented Clover detector
Shepherd, S L; Cullen, D M; Appelbe, D E; Simpson, J; Gerl, J; Kaspar, M; Kleinböhl, A; Peter, I; Rejmund, M; Schaffner, H; Schlegel, C; France, G D
1999-01-01
The performance of a segmented Clover germanium detector has been measured. The segmented Clover detector is a composite germanium detector, consisting of four individual germanium crystals in the configuration of a four-leaf Clover, housed in a single cryostat. Each crystal is electrically segmented on its outer surface into four quadrants, with separate energy read-outs from nine crystal zones. Signals are also taken from the inner contact of each crystal. This effectively produces a detector with 16 active elements. One of the purposes of this segmentation is to improve the overall spectral resolution when detecting gamma radiation emitted following a nuclear reaction, by minimising Doppler broadening caused by the opening angle subtended by each detector element. Results of the tests with sources and in beam will be presented. The improved granularity of the detector also leads to an improved isolated hit probability compared with an unsegmented Clover detector. (author)
Fold distributions at clover, crystal and segment levels for segmented clover detectors
International Nuclear Information System (INIS)
Kshetri, R; Bhattacharya, P
2014-01-01
Fold distributions at clover, crystal and segment levels have been extracted for an array of segmented clover detectors for various gamma energies. A simple analysis of the results based on a model independant approach has been presented. For the first time, the clover fold distribution of an array and associated array addback factor have been extracted. We have calculated the percentages of the number of crystals and segments that fire for a full energy peak event
Proportional crosstalk correction for the segmented clover at iThemba LABS
International Nuclear Information System (INIS)
Bucher, T D; Noncolela, S P; Lawrie, E A; Dinoko, T R S; Easton, J L; Erasmus, N; Lawrie, J J; Mthembu, S H; Mtshali, W X; Shirinda, O; Orce, J N
2017-01-01
Reaching new depths in nuclear structure investigations requires new experimental equipment and new techniques of data analysis. The modern γ -ray spectrometers, like AGATA and GRETINA are now built of new-generation segmented germanium detectors. These most advanced detectors are able to reconstruct the trajectory of a γ -ray inside the detector. These are powerful detectors, but they need careful characterization, since their output signals are more complex. For instance for each γ -ray interaction that occurs in a segment of such a detector additional output signals (called proportional crosstalk), falsely appearing as an independent (often negative) energy depositions, are registered on the non-interacting segments. A failure to implement crosstalk correction results in incorrectly measured energies on the segments for two- and higher-fold events. It affects all experiments which rely on the recorded segment energies. Furthermore incorrectly recorded energies on the segments cause a failure to reconstruct the γ -ray trajectories using Compton scattering analysis. The proportional crosstalk for the iThemba LABS segmented clover was measured and a crosstalk correction was successfully implemented. The measured crosstalk-corrected energies show good agreement with the true γ -ray energies independent on the number of hit segments and an improved energy resolution for the segment sum energy was obtained. (paper)
Modeling of clover detector in addback mode
Kshetri, R.
2012-07-01
Based on absorption and scattering of gamma-rays, a formalism has been presented for modeling the clover germanium detector in addback mode and to predict its response for high energy γ-rays. In the present formalism, the operation of a bare clover detector could be described in terms of three quantities only. Considering an additional parameter, the formalism could be extended for suppressed clover. Using experimental data on relative single crystal efficiency and addback factor as input, the peak-to-total ratio has been calculated for three energies (Eγ = 3.401, 5.324 and 10.430 MeV) where direct measurement of peak-to-total ratio is impossible due to absence of a radioactive source having single monoenergetic gamma-ray of that energy. The experimental validation and consistency of the formalism have been shown considering data for TIGRESS clover detector. In a recent work (R. Kshetri, JINST 2012 7 P04008), we showed that for a given γ-ray energy, the formalism could be used to predict the peak-to-total ratio as a function of number of detector modules. In the present paper, we have shown that for a given composite detector (clover detector is considered here), the formalism could be used to predict the peak-to-total ratio as a function of γ-ray energy.
Modeling of clover detector in addback mode
International Nuclear Information System (INIS)
Kshetri, R
2012-01-01
Based on absorption and scattering of gamma-rays, a formalism has been presented for modeling the clover germanium detector in addback mode and to predict its response for high energy γ-rays. In the present formalism, the operation of a bare clover detector could be described in terms of three quantities only. Considering an additional parameter, the formalism could be extended for suppressed clover. Using experimental data on relative single crystal efficiency and addback factor as input, the peak-to-total ratio has been calculated for three energies (E γ = 3.401, 5.324 and 10.430 MeV) where direct measurement of peak-to-total ratio is impossible due to absence of a radioactive source having single monoenergetic gamma-ray of that energy. The experimental validation and consistency of the formalism have been shown considering data for TIGRESS clover detector. In a recent work (R. Kshetri, JINST 2012 7 P04008), we showed that for a given γ-ray energy, the formalism could be used to predict the peak-to-total ratio as a function of number of detector modules. In the present paper, we have shown that for a given composite detector (clover detector is considered here), the formalism could be used to predict the peak-to-total ratio as a function of γ-ray energy.
A first principle approach for clover detector
Kshetri, R.
2012-08-01
A simple model based on probability flow arguments has been presented for understanding the clover germanium detector. Using basic concepts of absorption and scattering of gamma-rays, the operation of the clover detector has been described in terms of six probability amplitudes and a parameter. Instead of using an empirical method or simulation, this work presents the first attempt to calculate the peak-to-total and peak-to-background ratios of the clover detector using experimental data of relative single crystal efficiency and addback factor as an input. A unique feature of our approach is that these ratios could be calculated for energies where their direct measurement is impossible due to absence of a radioactive source having single monoenergetic gamma-ray of that energy. Results for four gamma-ray energies (Eγ = 1.408, 3.907, 7.029 and 10.430 MeV) have been discussed. Agreement between experimental data and analysis results has been observed. The present approach could describe clover-type detectors as well. As an example, the nine element detector has been considered. We have demonstrated that our formalism can describe both finite and infinite interactions of γ-rays with the clover crystals. The work presented in this paper follows similar philosophy as presented in a recent paper (R. Kshetri, JInst 2012 7 P04008), which deals with modeling of encapsulated type composite detectors like miniball, cluster and SPI (Spectrometer for INTEGRAL satellite).
A first principle approach for clover detector
International Nuclear Information System (INIS)
Kshetri, R
2012-01-01
A simple model based on probability flow arguments has been presented for understanding the clover germanium detector. Using basic concepts of absorption and scattering of gamma-rays, the operation of the clover detector has been described in terms of six probability amplitudes and a parameter. Instead of using an empirical method or simulation, this work presents the first attempt to calculate the peak-to-total and peak-to-background ratios of the clover detector using experimental data of relative single crystal efficiency and addback factor as an input. A unique feature of our approach is that these ratios could be calculated for energies where their direct measurement is impossible due to absence of a radioactive source having single monoenergetic gamma-ray of that energy. Results for four gamma-ray energies (E γ = 1.408, 3.907, 7.029 and 10.430 MeV) have been discussed. Agreement between experimental data and analysis results has been observed. The present approach could describe clover-type detectors as well. As an example, the nine element detector has been considered. We have demonstrated that our formalism can describe both finite and infinite interactions of γ-rays with the clover crystals. The work presented in this paper follows similar philosophy as presented in a recent paper (R. Kshetri, JInst 2012 7 P04008), which deals with modeling of encapsulated type composite detectors like miniball, cluster and SPI (Spectrometer for INTEGRAL satellite).
Energy Technology Data Exchange (ETDEWEB)
Beck, F A; Byrski, Th; Durien, D; Duchene, G; France, G de; Kharraja, B; Wei, L [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Butler, P; Jones, G; Jones, P [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Hannachi, F [Daresbury Lab. (United Kingdom)
1992-08-01
The EUROGAM Phase I device is almost running for experiments and new technical developments are in progress for its second phase. For example, a composite Ge detector should enable: a very large photopeak efficiency with good energy and timing resolutions; and, the covering, with Ge, of a large portion of 4{pi}-Str. The Clover detector, proposed by the CRN, Strasbourg, is one of this new generation of Ge detectors. It is currently developed in France by the EUROGAM collaboration. The design, the technical characteristics of the counter and the first results of the prototype tests are discussed in this contribution. (author). 1 ref., 2 tabs., 2 refs.
Analysis of fold distributions of segmented clover detectors
International Nuclear Information System (INIS)
Bhattacharya, Pintu; Kshetri, Ritesh
2015-01-01
We have studied the effect of segmentation on the full energy energy deposition of a gamma-ray through the studies on fold distribution. The response of seven segmented TIGRESS detectors up to an energy of 8 MeV has been studied by utilizing standard sources of 152 Eu, 56,60 Co and a radioactive 11 Be beam with an energy of 16.5 MeV. Experiment was performed at the ISAC-II facility at TRIUMF, using a thick gold target. The β¯ decay of 11 Be (τ 1/2 = 13.81(8) sec) produces high energy gamma-rays up to 7974 keV. A 1 mm thick annular double-sided silicon detector of the BAMBINO detector, was mounted 19.4 mm downstream of the target position and used for detection of the electrons in coincidence with the gamma-rays from the seven TIGRESS detectors. The master trigger allowed data to be collected either in Ge singles mode or with a Ge-Si coincidence condition. Standard sources of 152 Eu and 56,60 Co were also used to obtain low energy data
Measured and simulated performance of Compton-suppressed TIGRESS HPGe clover detectors
Schumaker, M. A.; Hackman, G.; Pearson, C. J.; Svensson, C. E.; Andreoiu, C.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Boston, A. J.; Chakrawarthy, R. S.; Churchman, R.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Jones, B.; Maharaj, R.; Morton, A. C.; Phillips, A. A.; Sarazin, F.; Scraggs, H. C.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.
2007-01-01
Tests of the performance of a 32-fold segmented HPGe clover detector coupled to a 20-fold segmented Compton-suppression shield, which form a prototype element of the TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS), have been made. Peak-to-total ratios and relative efficiencies have been measured for a variety of γ-ray energies. These measurements were used to validate a GEANT4 simulation of the TIGRESS detectors, which was then used to create a simulation of the full 12-detector array. Predictions of the expected performance of TIGRESS are presented. These predictions indicate that TIGRESS will be capable, for single 1 MeV γ rays, of absolute detection efficiencies of 17% and 9.4%, and peak-to-total ratios of 54% and 61% for the "high-efficiency" and "optimized peak-to-total" configurations of the array, respectively.
Performance comparison for modes of operation and suppression cases of the clover detector
International Nuclear Information System (INIS)
Kshetri, R
2014-01-01
Peak-to-total ratios have been extracted for a segmented clover detector for various modes of operation and suppression cases. Based on absorption and scattering of gamma-rays, a formalism has been presented for quantifying the advantages of using addback mode and active suppression. Further investigations have been performed to find if the reduction of background counts is caused more by active suppression or by addback process
Position sensitivity of the proposed segmented germanium detectors for the DESPEC project
International Nuclear Information System (INIS)
Khaplanov, A.; Tashenov, S.; Cederwall, B.
2009-01-01
The DESPEC HPGe array is a part of the NuSTAR project at FAIR, Germany. It is aimed at the spectroscopy of the stopped decaying exotic nuclei. Segmented γ-ray tracking detectors are proposed for this array in order to maximize detection efficiency and background suppression when searching for very rare events. Two types of detector modules-stacks of three 16-fold segmented planar crystals and 12- and 16-fold segmented clover detectors-have been investigated and compared from the point of view of the achievable position resolution using pulse shape analysis (PSA). To this end, detector signals from realistic γ-ray interactions have been calculated. These signals were treated by PSA in order to reconstruct the photon interaction locations. Comparing the initial interaction locations to the reconstructed ones, it was found that the double-sided strip planar detector yielded position reconstruction errors at least a factor 2 lower than the other detectors considered.
TIGRESS highly-segmented high-purity germanium clover detector
Scraggs, H. C.; Pearson, C. J.; Hackman, G.; Smith, M. B.; Austin, R. A. E.; Ball, G. C.; Boston, A. J.; Bricault, P.; Chakrawarthy, R. S.; Churchman, R.; Cowan, N.; Cronkhite, G.; Cunningham, E. S.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Jones, B.; Leslie, J. R.; Martin, J.-P.; Morris, D.; Morton, A. C.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Svensson, C. E.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.; Zimmerman, L.
2005-05-01
The TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS) will consist of twelve units of four high-purity germanium (HPGe) crystals in a common cryostat. The outer contacts of each crystal will be divided into four quadrants and two lateral segments for a total of eight outer contacts. The performance of a prototype HPGe four-crystal unit has been investigated. Integrated noise spectra for all contacts were measured. Energy resolutions, relative efficiencies for both individual crystals and for the entire unit, and peak-to-total ratios were measured with point-like sources. Position-dependent performance was measured by moving a collimated source across the face of the detector.
Analysis of the effects of pair production for the suppressed clover detector
International Nuclear Information System (INIS)
Kshetri, R.
2014-01-01
Full energy peak, single escape peak and double escape peak areas have been extracted for an escape suppressed clover detector. Results have been obtained for the single crystal and addback modes of operation as well as the active and passive suppression cases at several gamma energies. We have compared the ratio of single escape peak areas in addback mode with that of single crystal mode to study if the single escape peak gains or loses counts due to addback mode. Detailed analysis has been performed for quantifying the advantages of using addback mode and active suppression. Comparison is made for different types of clover detectors with different volumes
DEFF Research Database (Denmark)
Skovsen, Søren; Dyrmann, Mads; Eriksen, Jørgen
2018-01-01
species in the biomass. In our setup, we exploit the top-down canopy view of the clover grass ley to estimate the volumetric composition of the yield, and predict the composition of the dry matter of the forage. Using a deep learning approach, the canopy image is automatically pixel-wise segmented....... The biggest hindrance to training a fully convolutional deep neural network is the requirement of labeled data. Due to the complexity, the high number of leaves and high levels of occlusions in clover grass canopies, hand labeling the data requires roughly 20 hours of manual labor per image. The need...... for hundreds or thousands labeled training images renders this approach unfeasible. We have shown that implementation of image simulation of distinct clover grass fields can reduce the labeling task significantly. Investing less than 20 hours of labor, thousands of simulated images and corresponding labels can...
Full energy peak efficiency of composite detectors for high energy gamma-rays
International Nuclear Information System (INIS)
Kshetri, Ritesh
2015-01-01
Experiments involving radioactive beams demand high detection efficiencies. One of the ways to obtain high detection efficiency without deteriorating the energy resolution or timing characteristics is the use of composite detectors which are composed of standard HPGe crystals arranged in a compact way. Two simplest composite detectors are the clover and cluster detectors. The TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS) comprises of 16 large volume, 32-fold segmented HPGe clover detectors, where each detector is shielded by a 20-fold segmented escape suppression shield (ESS)
International Nuclear Information System (INIS)
Saha Sarkar, M.; Kshetri, Ritesh; Raut, Rajarshi; Mukherjee, A.; Goswami, A.; Ray, S.; Basu, P.; Majumder, H.; Bhattacharya, S.; Dasmahapatra, B.; Sinha, Mandira; Ray, Maitreyee
2004-01-01
The Clover detectors in their add back mode have been seen to be excellent tools for detecting high energy gamma rays (≥ 2 MeV). Recently studies were carried out on the characteristics of a Compton suppressed Clover germanium detector up to 5 MeV using a radioactive 66 Ga (T 1/2 =9.41 h) source for the first time
Directory of Open Access Journals (Sweden)
Anders K. Mortensen
2017-12-01
Full Text Available The clover-grass ratio is an important factor in composing feed ratios for livestock. Cameras in the field allow the user to estimate the clover-grass ratio using image analysis; however, current methods assume the total dry matter is known. This paper presents the preliminary results of an image analysis method for non-destructively estimating the total dry matter of clover-grass. The presented method includes three steps: (1 classification of image illumination using a histogram of the difference in excess green and excess red; (2 segmentation of clover and grass using edge detection and morphology; and (3 estimation of total dry matter using grass coverage derived from the segmentation and climate parameters. The method was developed and evaluated on images captured in a clover-grass plot experiment during the spring growing season. The preliminary results are promising and show a high correlation between the image-based total dry matter estimate and the harvested dry matter ( R 2 = 0.93 with an RMSE of 210 kg ha − 1 .
Measurements and simulation-based optimization of TIGRESS HPGe detector array performance
International Nuclear Information System (INIS)
Schumaker, M.A.
2005-01-01
TIGRESS is a new γ-ray detector array being developed for installation at the new ISAC-II facility at TRIUMF in Vancouver. When complete, it will consist of twelve large-volume segmented HPGe clover detectors, fitted with segmented Compton suppression shields. The combined operation of prototypes of both a TIGRESS detector and a suppression shield has been tested. Peak-to-total ratios, relative photopeak efficiencies, and energy resolution functions have been determined in order to characterize the performance of TIGRESS. This information was then used to refine a GEANT4 simulation of the full detector array. Using this simulation, methods to overcome the degradation of the photopeak efficiency and peak-to-total response that occurs with high γ-ray multiplicity events were explored. These methods take advantage of the high segmentation of both the HPGe clovers and the suppression shields to suppress or sum detector interactions selectively. For a range of γ-ray energies and multiplicities, optimal analysis methods have been determined, which has resulted in significant gains in the expected performance of TIGRESS. (author)
Energy Technology Data Exchange (ETDEWEB)
Bleuel, D L; Bernstein, L A; Burke, J T; Gibelin, J; Heffner, M D; Mintz, J; Norman, E B; Phair, L; Scielzo, N D; Sheets, S A; Snyderman, N J; Stoyer, M A; Wiedeking, M
2008-04-23
Coincident {gamma} rays from a {sup 252}Cf source were measured using an array of six segmented high-purity germanium (HPGe) Clover detectors each enclosed by 16 bismuth-germanate (BGO) detectors. The detectors were arranged in a cubic pattern around a 1 {micro}Ci {sup 252}Cf source to cover a large solid angle for {gamma}-ray measurement with a reasonable reconstruction of the multiplicity. Neutron multiplicity was determined in certain cases by identifying the prompt {gamma} rays from individual fission fragment pairs. Multiplicity distributions from previous experiments and theoretical models were convolved with the response function of the array and compared to the present results. These results suggest a {gamma}-ray multiplicity spectrum broader than previous measurements and models, and provide no evidence of correlation with neutron multiplicity.
Characterisation of a Compton suppressed Clover detector for high energy gamma rays (=<11MeV)
International Nuclear Information System (INIS)
Saha Sarkar, M.; Kshetri, Ritesh; Raut, Rajarshi; Mukherjee, A.; Sinha, Mandira; Ray, Maitreyi; Goswami, A.; Roy, Subinit; Basu, P.; Majumder, H.; Bhattacharya, S.; Dasmahapatra, B.
2006-01-01
Gamma ray spectra of two (p,γ) resonances have been utilised for the characterisation of the Clover detector at energies beyond 5MeV. Apart from the efficiency and the resolution of the detector, the shapes of the full energy peaks as well as the nature of the escape peaks which are also very crucial at higher energies have been analysed with special attention. Proper gain matching in software have checked deterioration in the energy resolution and distortion in the peak shape due to addback. The addback factors show sharp increasing trend even at energies around 11MeV
Characterisation of a Compton suppressed Clover detector for high energy gamma rays (=<11MeV)
Energy Technology Data Exchange (ETDEWEB)
Saha Sarkar, M. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India)]. E-mail: maitrayee.sahasarkar@saha.ac.in; Kshetri, Ritesh [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Raut, Rajarshi [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Mukherjee, A. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Sinha, Mandira [Gurudas College, Narkeldanga, Kolkata-700054 (India); Ray, Maitreyi [Behala College, Parnashree, Kolkata-700060 (India); Goswami, A. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Roy, Subinit [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Basu, P. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Majumder, H. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Bhattacharya, S. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Dasmahapatra, B. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India)
2006-01-01
Gamma ray spectra of two (p,{gamma}) resonances have been utilised for the characterisation of the Clover detector at energies beyond 5MeV. Apart from the efficiency and the resolution of the detector, the shapes of the full energy peaks as well as the nature of the escape peaks which are also very crucial at higher energies have been analysed with special attention. Proper gain matching in software have checked deterioration in the energy resolution and distortion in the peak shape due to addback. The addback factors show sharp increasing trend even at energies around 11MeV.
International Nuclear Information System (INIS)
Kumar, Manish; Kamble, S.R.; Chaudhari, A.T.; Sabharwal, T.P.; Pathak, Kavindra; Prasad, N.K.; Kinage, L.A.; Biswas, D.C.; Bhagwat, P.V.
2017-01-01
Nuclear spectroscopy has been studied earlier from the measurement of prompt gamma rays produced in reactions with thermal neutrons from CIRUS reactor. For studying the prompt γ-spectroscopy using thermal neutrons from Dhruva Reactor, BARC, the development of a dedicated beam line (R-3001) is in progress. In this beam line a detector assembly consisting of Clover Ge detectors will be used. This experimental setup will be utilized to investigate nuclear structure using prompt (n,γ) reactions and also to study the spectroscopy of neutron-rich fission-fragment nuclei
The hyperion particle-γ detector array
Energy Technology Data Exchange (ETDEWEB)
Hughes, R.O.; Burke, J.T.; Casperson, R.J.; Ota, S. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Fisher, S.; Parker, J. [Science, Technology and Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Beausang, C.W. [Department of Physics, University of Richmond, 28 Westhampton Way, Richmond, VA 23173 (United States); Dag, M. [Cyclotron Institute, Texas A& M University, College Station, TX 77840 (United States); Humby, P. [Department of Physics, University of Richmond, 28 Westhampton Way, Richmond, VA 23173 (United States); Department of Physics, University of Surrey, Surrey GU27XH (United Kingdom); Koglin, J. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); McCleskey, E.; McIntosh, A.B.; Saastamoinen, A. [Cyclotron Institute, Texas A& M University, College Station, TX 77840 (United States); Tamashiro, A.S. [Department of Nuclear Science and Engineering, Oregon State University, Corvallis, OR 97331 (United States); Wilson, E. [Department of Physics, University of Richmond, 28 Westhampton Way, Richmond, VA 23173 (United States); Wu, T.C. [Department of Physics and Astronomy, University of Utah, Salt Lake City UT 84112-0830 (United States)
2017-06-01
Hyperion is a new high-efficiency charged-particle γ-ray detector array which consists of a segmented silicon telescope for charged-particle detection and up to fourteen high-purity germanium clover detectors for the detection of coincident γ rays. The array will be used in nuclear physics measurements and Stockpile Stewardship studies and replaces the STARLiTeR array. This article discusses the features of the array and presents data collected with the array in the commissioning experiment.
Pulse shapes and surface effects in segmented germanium detectors
Energy Technology Data Exchange (ETDEWEB)
Lenz, Daniel
2010-03-24
It is well established that at least two neutrinos are massive. The absolute neutrino mass scale and the neutrino hierarchy are still unknown. In addition, it is not known whether the neutrino is a Dirac or a Majorana particle. The GERmanium Detector Array (GERDA) will be used to search for neutrinoless double beta decay of {sup 76}Ge. The discovery of this decay could help to answer the open questions. In the GERDA experiment, germanium detectors enriched in the isotope {sup 76}Ge are used as source and detector at the same time. The experiment is planned in two phases. In the first, phase existing detectors are deployed. In the second phase, additional detectors will be added. These detectors can be segmented. A low background index around the Q value of the decay is important to maximize the sensitivity of the experiment. This can be achieved through anti-coincidences between segments and through pulse shape analysis. The background index due to radioactive decays in the detector strings and the detectors themselves was estimated, using Monte Carlo simulations for a nominal GERDA Phase II array with 18-fold segmented germanium detectors. A pulse shape simulation package was developed for segmented high-purity germanium detectors. The pulse shape simulation was validated with data taken with an 19-fold segmented high-purity germanium detector. The main part of the detector is 18-fold segmented, 6-fold in the azimuthal angle and 3-fold in the height. A 19th segment of 5mm thickness was created on the top surface of the detector. The detector was characterized and events with energy deposited in the top segment were studied in detail. It was found that the metalization close to the end of the detector is very important with respect to the length of the of the pulses observed. In addition indications for n-type and p-type surface channels were found. (orig.)
Pulse shapes and surface effects in segmented germanium detectors
International Nuclear Information System (INIS)
Lenz, Daniel
2010-01-01
It is well established that at least two neutrinos are massive. The absolute neutrino mass scale and the neutrino hierarchy are still unknown. In addition, it is not known whether the neutrino is a Dirac or a Majorana particle. The GERmanium Detector Array (GERDA) will be used to search for neutrinoless double beta decay of 76 Ge. The discovery of this decay could help to answer the open questions. In the GERDA experiment, germanium detectors enriched in the isotope 76 Ge are used as source and detector at the same time. The experiment is planned in two phases. In the first, phase existing detectors are deployed. In the second phase, additional detectors will be added. These detectors can be segmented. A low background index around the Q value of the decay is important to maximize the sensitivity of the experiment. This can be achieved through anti-coincidences between segments and through pulse shape analysis. The background index due to radioactive decays in the detector strings and the detectors themselves was estimated, using Monte Carlo simulations for a nominal GERDA Phase II array with 18-fold segmented germanium detectors. A pulse shape simulation package was developed for segmented high-purity germanium detectors. The pulse shape simulation was validated with data taken with an 19-fold segmented high-purity germanium detector. The main part of the detector is 18-fold segmented, 6-fold in the azimuthal angle and 3-fold in the height. A 19th segment of 5mm thickness was created on the top surface of the detector. The detector was characterized and events with energy deposited in the top segment were studied in detail. It was found that the metalization close to the end of the detector is very important with respect to the length of the of the pulses observed. In addition indications for n-type and p-type surface channels were found. (orig.)
Segmentation of the Outer Contact on P-Type Coaxial Germanium Detectors
Energy Technology Data Exchange (ETDEWEB)
Hull, Ethan L.; Pehl, Richard H.; Lathrop, James R.; Martin, Gregory N.; Mashburn, R. B.; Miley, Harry S.; Aalseth, Craig E.; Hossbach, Todd W.
2006-09-21
Germanium detector arrays are needed for low-level counting facilities. The practical applications of such user facilities include characterization of low-level radioactive samples. In addition, the same detector arrays can also perform important fundamental physics measurements including the search for rare events like neutrino-less double-beta decay. Coaxial germanium detectors having segmented outer contacts will provide the next level of sensitivity improvement in low background measurements. The segmented outer detector contact allows performance of advanced pulse shape analysis measurements that provide additional background reduction. Currently, n-type (reverse electrode) germanium coaxial detectors are used whenever a segmented coaxial detector is needed because the outer boron (electron barrier) contact is thin and can be segmented. Coaxial detectors fabricated from p-type germanium cost less, have better resolution, and are larger than n-type coaxial detectors. However, it is difficult to reliably segment p-type coaxial detectors because thick (~1 mm) lithium-diffused (hole barrier) contacts are the standard outside contact for p-type coaxial detectors. During this Phase 1 Small Business Innovation Research (SBIR) we have researched the possibility of using amorphous germanium contacts as a thin outer contact of p-type coaxial detectors that can be segmented. We have developed amorphous germanium contacts that provide a very high hole barrier on small planar detectors. These easily segmented amorphous germanium contacts have been demonstrated to withstand several thousand volts/cm electric fields with no measurable leakage current (<1 pA) from charge injection over the hole barrier. We have also demonstrated that the contact can be sputter deposited around and over the curved outside surface of a small p-type coaxial detector. The amorphous contact has shown good rectification properties on the outside of a small p-type coaxial detector. These encouraging
Segmented focal plane detector for light and heavy ions
International Nuclear Information System (INIS)
Wolfs, F.L.H.; Bryan, D.C.; Kurz, K.L.; Herrick, D.M.; Perera, P.A.A.; White, C.A.
1992-01-01
A segmented focal plane detector for an Enge split-pole spectrograph has been developed for the study of breakup reactions at very low relative energies. It consists of a 61 cm long segmented position-sensitive parallel plate avalanche counter backed by a large Bragg curve detector. A segmented plastic scintillator is mounted behind the anode of the Bragg curve detector and is used for particle identification of low-ionizing particles. The dead space between the two sections of the focal plane detector is 2.5 mm. The intrinsic position resolution of the detector is 1 mm. The intrinsic energy resolution depends on the energy of the incident ion and can be as good as 0.55%. The nuclear charge and mass resolutions are 0.3 e and 0.3 u, respectively. (orig.)
Pulse shape analysis optimization with segmented HPGe-detectors
Energy Technology Data Exchange (ETDEWEB)
Lewandowski, Lars; Birkenbach, Benedikt; Reiter, Peter [Institute for Nuclear Physics, University of Cologne (Germany); Bruyneel, Bart [CEA, Saclay (France); Collaboration: AGATA-Collaboration
2014-07-01
Measurements with the position sensitive, highly segmented AGATA HPGe detectors rely on the gamma-ray-tracking GRT technique which allows to determine the interaction point of the individual gamma-rays hitting the detector. GRT is based on a pulse shape analysis PSA of the preamplifier signals from the 36 segments and the central electrode of the detector. The achieved performance and position resolution of the AGATA detector is well within the specifications. However, an unexpected inhomogeneous distribution of interaction points inside the detector volume is observed as a result of the PSA even when the measurement is performed with an isotropically radiating gamma ray source. The clustering of interaction points motivated a study in order to optimize the PSA algorithm or its ingredients. Position resolution results were investigated by including contributions from differential crosstalk of the detector electronics, an improved preamplifier response function and a new time alignment. Moreover the spatial distribution is quantified by employing different χ{sup 2}-minimization procedures.
Crosstalk properties of 36-fold segmented symmetric hexagonal HPGe detectors
International Nuclear Information System (INIS)
Bruyneel, Bart; Reiter, Peter; Wiens, Andreas; Eberth, Juergen; Hess, Herbert; Pascovici, Gheorghe; Warr, Nigel; Weisshaar, Dirk
2009-01-01
Crosstalk properties of three 36-fold segmented, symmetric, large volume, HPGe detectors from the AGATA Collaboration were deduced from coincidence measurements performed with digitized segment and core signals after interaction of γ rays with energies of 1.33 MeV. The mean energy values measured by the core signal fluctuate for γ-ray interactions with energy deposited in two segments. A regular pattern is observed depending on the hit segment combinations. The core energy shifts deviate 0.03-0.06% from the average energy calibration. The segment-sum energy is reduced with respect to the core energy as a function of the decoupling capacitance and the segment multiplicity. The deviation of the segment-sum energies from multiplicity two events fluctuates within an interval of less than 0.1% depending on the different segment combinations. The energy shifts caused by crosstalk for the core and segment signals are comparable for all three detectors. A linear electronic model of the detector and preamplifier assembly was developed to evaluate the results. The fold-dependent energy shifts of the segment-sum energies are reproduced. The model yields a constant shift in all segments, proportional to the core signal. The measured crosstalk pattern and its intensity variation in the segments agree well with the calculated values. The regular variation observed in the core energies cannot be directly related to crosstalk and may be caused by other effects like electron trapping.
Development of segmented germanium detectors for neutrinoless double beta decay experiments
International Nuclear Information System (INIS)
Liu, Jing
2009-01-01
The results from neutrino oscillation experiments indicate that at least two neutrinos have mass. However, the value of the masses and whether neutrinos and anti-neutrinos are identical, i.e., Majorana particles, remain unknown. Neutrinoless double beta decay experiments can help to improve our understanding in both cases and are the only method currently possible to tackle the second question. The GERmanium Detector Array (GERDA) experiment, which will search for the neutrinoless double beta decay of 76 Ge, is currently under construction in Hall A of the INFN Gran Sasso National Laboratory (LNGS), Italy. In order to achieve an extremely low background level, segmented germanium detectors are considered to be operated directly in liquid argon which serves simultaneously as cooling and shielding medium. Several test cryostats were built at the Max-Planck-Institut fuer Physik in Muenchen to operate segmented germanium detectors both in vacuum and submerged in cryogenic liquid. The performance and the background discrimination power of segmented germanium detectors were studied in detail. It was proven for the first time that segmented germanium detectors can be operated stably over long periods submerged in a cryogenic liquid. It was confirmed that the segmentation scheme employed does well in the identification of photon induced background and demonstrated for the first time that also neutron interactions can be identified. The C++ Monte Carlo framework, MaGe (Majorana-GERDA), is a joint development of the Majorana and GERDA collaborations. It is based on GEANT4, but tailored especially to simulate the response of ultra-low background detectors to ionizing radiation. The predictions of the simulation were veri ed to be accurate for a wide range of conditions. Some shortcomings were found and corrected. Pulse shape analysis is complementary to segmentation in identifying background events. Its efficiency can only be correctly determined using reliable pulse shape
Development of segmented germanium detectors for neutrinoless double beta decay experiments
Energy Technology Data Exchange (ETDEWEB)
Liu, Jing
2009-06-09
The results from neutrino oscillation experiments indicate that at least two neutrinos have mass. However, the value of the masses and whether neutrinos and anti-neutrinos are identical, i.e., Majorana particles, remain unknown. Neutrinoless double beta decay experiments can help to improve our understanding in both cases and are the only method currently possible to tackle the second question. The GERmanium Detector Array (GERDA) experiment, which will search for the neutrinoless double beta decay of {sup 76}Ge, is currently under construction in Hall A of the INFN Gran Sasso National Laboratory (LNGS), Italy. In order to achieve an extremely low background level, segmented germanium detectors are considered to be operated directly in liquid argon which serves simultaneously as cooling and shielding medium. Several test cryostats were built at the Max-Planck-Institut fuer Physik in Muenchen to operate segmented germanium detectors both in vacuum and submerged in cryogenic liquid. The performance and the background discrimination power of segmented germanium detectors were studied in detail. It was proven for the first time that segmented germanium detectors can be operated stably over long periods submerged in a cryogenic liquid. It was confirmed that the segmentation scheme employed does well in the identification of photon induced background and demonstrated for the first time that also neutron interactions can be identified. The C++ Monte Carlo framework, MaGe (Majorana-GERDA), is a joint development of the Majorana and GERDA collaborations. It is based on GEANT4, but tailored especially to simulate the response of ultra-low background detectors to ionizing radiation. The predictions of the simulation were veri ed to be accurate for a wide range of conditions. Some shortcomings were found and corrected. Pulse shape analysis is complementary to segmentation in identifying background events. Its efficiency can only be correctly determined using reliable pulse
Crystal Structure of Green Fluorescent Protein Clover and Design of Clover-Based Redox Sensors.
Campbell, Benjamin C; Petsko, Gregory A; Liu, Ce Feng
2018-02-06
We have determined the crystal structure of Clover, one of the brightest fluorescent proteins, and found that its T203H/S65G mutations relative to wild-type GFP lock the critical E222 side chain in a fixed configuration that mimics the major conformer of that in EGFP. The resulting equilibrium shift to the predominantly deprotonated chromophore increases the extinction coefficient (EC), opposes photoactivation, and is responsible for the bathochromic shift. Clover's brightness can further be attributed to a π-π stacking interaction between H203 and the chromophore. Consistent with these observations, the Clover G65S mutant reversed the equilibrium shift, dramatically decreased the EC, and made Clover photoactivatable under conditions that activated photoactivatable GFP. Using the Clover structure, we rationally engineered a non-photoactivatable redox sensor, roClover1, and determined its structure as well as that of its parental template, roClover0.1. These high-resolution structures provide deeper insights into structure-function relationships in GFPs and may aid the development of excitation-improved ratiometric biosensors. Copyright © 2017 Elsevier Ltd. All rights reserved.
Compton imaging with a highly-segmented, position-sensitive HPGe detector
Energy Technology Data Exchange (ETDEWEB)
Steinbach, T.; Hirsch, R.; Reiter, P.; Birkenbach, B.; Bruyneel, B.; Eberth, J.; Hess, H.; Lewandowski, L. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Gernhaeuser, R.; Maier, L.; Schlarb, M.; Weiler, B.; Winkel, M. [Technische Universitaet Muenchen, Physik Department, Garching (Germany)
2017-02-15
A Compton camera based on a highly-segmented high-purity germanium (HPGe) detector and a double-sided silicon-strip detector (DSSD) was developed, tested, and put into operation; the origin of γ radiation was determined successfully. The Compton camera is operated in two different modes. Coincidences from Compton-scattered γ-ray events between DSSD and HPGe detector allow for best angular resolution; while the high-efficiency mode takes advantage of the position sensitivity of the highly-segmented HPGe detector. In this mode the setup is sensitive to the whole 4π solid angle. The interaction-point positions in the 36-fold segmented large-volume HPGe detector are determined by pulse-shape analysis (PSA) of all HPGe detector signals. Imaging algorithms were developed for each mode and successfully implemented. The angular resolution sensitively depends on parameters such as geometry, selected multiplicity and interaction-point distances. Best results were obtained taking into account the crosstalk properties, the time alignment of the signals and the distance metric for the PSA for both operation modes. An angular resolution between 13.8 {sup circle} and 19.1 {sup circle}, depending on the minimal interaction-point distance for the high-efficiency mode at an energy of 1275 keV, was achieved. In the coincidence mode, an increased angular resolution of 4.6 {sup circle} was determined for the same γ-ray energy. (orig.)
Sub-nanosecond time-of-flight for segmented silicon detectors
International Nuclear Information System (INIS)
Souza, R.T. de; Alexander, A.; Brown, K.; Floyd, B.; Gosser, Z.Q.; Hudan, S.; Poehlman, J.; Rudolph, M.J.
2011-01-01
Development of a multichannel time-of-flight system for readout of a segmented, ion-passivated, ion-implanted silicon detector is described. This system provides sub-nanosecond resolution (δt∼370ps) even for low energy α particles which deposit E≤7.687MeV in the detector.
The position response of a large-volume segmented germanium detector
International Nuclear Information System (INIS)
Descovich, M.; Nolan, P.J.; Boston, A.J.; Dobson, J.; Gros, S.; Cresswell, J.R.; Simpson, J.; Lazarus, I.; Regan, P.H.; Valiente-Dobon, J.J.; Sellin, P.; Pearson, C.J.
2005-01-01
The position response of a large-volume segmented coaxial germanium detector is reported. The detector has 24-fold segmentation on its outer contact. The output from each contact was sampled with fast digital signal processing electronics in order to determine the position of the γ-ray interaction from the signal pulse shape. The interaction position was reconstructed in a polar coordinate system by combining the radial information, contained in the rise-time of the pulse leading edge, with the azimuthal information, obtained from the magnitude of the transient charge signals induced on the neighbouring segments. With this method, a position resolution of 3-7mm is achieved in both the radial and the azimuthal directions
The position response of a large-volume segmented germanium detector
Energy Technology Data Exchange (ETDEWEB)
Descovich, M. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom)]. E-mail: mdescovich@lbl.gov; Nolan, P.J. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Boston, A.J. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Dobson, J. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Gros, S. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Cresswell, J.R. [Oliver Lodge Laboratory, Physics Department, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Simpson, J. [CCLRC Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Lazarus, I. [CCLRC Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Regan, P.H. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Valiente-Dobon, J.J. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Sellin, P. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Pearson, C.J. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom)
2005-11-21
The position response of a large-volume segmented coaxial germanium detector is reported. The detector has 24-fold segmentation on its outer contact. The output from each contact was sampled with fast digital signal processing electronics in order to determine the position of the {gamma}-ray interaction from the signal pulse shape. The interaction position was reconstructed in a polar coordinate system by combining the radial information, contained in the rise-time of the pulse leading edge, with the azimuthal information, obtained from the magnitude of the transient charge signals induced on the neighbouring segments. With this method, a position resolution of 3-7mm is achieved in both the radial and the azimuthal directions.
International Nuclear Information System (INIS)
Kroeninger, K.
2007-01-01
Two techniques to distinguish between electron and photon induced events in germanium detectors were studied: (1) anti-coincidence requirements between the segments of segmented germanium detectors and (2) the analysis of the time structure of the detector response. An 18-fold segmented germanium prototype detector for the GERDA neutrinoless double beta-decay experiment was characterized. The rejection of photon induced events was measured for the strongest lines in 60 Co, 152 Eu and 228 Th. An accompanying Monte Carlo simulation was performed and the results were compared to data. An overall agreement with deviations of the order of 5-10% was obtained. The expected background index of the GERDA experiment was estimated. The sensitivity of the GERDA experiment was determined. Special statistical tools were developed to correctly treat the small number of events expected. The GERDA experiment uses a cryogenic liquid as the operational medium for the germanium detectors. It was shown that germanium detectors can be reliably operated through several cooling cycles. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Kroeninger, K.
2007-06-05
Two techniques to distinguish between electron and photon induced events in germanium detectors were studied: (1) anti-coincidence requirements between the segments of segmented germanium detectors and (2) the analysis of the time structure of the detector response. An 18-fold segmented germanium prototype detector for the GERDA neutrinoless double beta-decay experiment was characterized. The rejection of photon induced events was measured for the strongest lines in {sup 60}Co, {sup 152}Eu and {sup 228}Th. An accompanying Monte Carlo simulation was performed and the results were compared to data. An overall agreement with deviations of the order of 5-10% was obtained. The expected background index of the GERDA experiment was estimated. The sensitivity of the GERDA experiment was determined. Special statistical tools were developed to correctly treat the small number of events expected. The GERDA experiment uses a cryogenic liquid as the operational medium for the germanium detectors. It was shown that germanium detectors can be reliably operated through several cooling cycles. (orig.)
High-resolution imaging gamma-ray spectroscopy with externally segmented germanium detectors
Callas, J. L.; Mahoney, W. A.; Varnell, L. S.; Wheaton, W. A.
1993-01-01
Externally segmented germanium detectors promise a breakthrough in gamma-ray imaging capabilities while retaining the superb energy resolution of germanium spectrometers. An angular resolution of 0.2 deg becomes practical by combining position-sensitive germanium detectors having a segment thickness of a few millimeters with a one-dimensional coded aperture located about a meter from the detectors. Correspondingly higher angular resolutions are possible with larger separations between the detectors and the coded aperture. Two-dimensional images can be obtained by rotating the instrument. Although the basic concept is similar to optical or X-ray coded-aperture imaging techniques, several complicating effects arise because of the penetrating nature of gamma rays. The complications include partial transmission through the coded aperture elements, Compton scattering in the germanium detectors, and high background count rates. Extensive electron-photon Monte Carlo modeling of a realistic detector/coded-aperture/collimator system has been performed. Results show that these complicating effects can be characterized and accounted for with no significant loss in instrument sensitivity.
Energy Technology Data Exchange (ETDEWEB)
Bruyneel, B. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Service de Physique Nucleaire, CEA Saclay, Gif-sur-Yvette (France); Birkenbach, B.; Reiter, P. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany)
2016-03-15
The AGATA Detector Library (ADL) was developed for the calculation of signals from highly segmented large volume high-purity germanium (HPGe) detectors. ADL basis sets comprise a huge amount of calculated position-dependent detector pulse shapes. A basis set is needed for Pulse Shape Analysis (PSA). By means of PSA the interaction position of a γ -ray inside the active detector volume is determined. Theoretical concepts of the calculations are introduced and cover the relevant aspects of signal formation in HPGe. The approximations and the realization of the computer code with its input parameters are explained in detail. ADL is a versatile and modular computer code; new detectors can be implemented in this library. Measured position resolutions of the AGATA detectors based on ADL are discussed. (orig.)
High-Resolution Gamma-Ray Imaging Measurements Using Externally Segmented Germanium Detectors
Callas, J.; Mahoney, W.; Skelton, R.; Varnell, L.; Wheaton, W.
1994-01-01
Fully two-dimensional gamma-ray imaging with simultaneous high-resolution spectroscopy has been demonstrated using an externally segmented germanium sensor. The system employs a single high-purity coaxial detector with its outer electrode segmented into 5 distinct charge collection regions and a lead coded aperture with a uniformly redundant array (URA) pattern. A series of one-dimensional responses was collected around 511 keV while the system was rotated in steps through 180 degrees. A non-negative, linear least-squares algorithm was then employed to reconstruct a 2-dimensional image. Corrections for multiple scattering in the detector, and the finite distance of source and detector are made in the reconstruction process.
A segmented, enriched N-type germanium detector for neutrinoless double beta-decay experiments
Leviner, L. E.; Aalseth, C. E.; Ahmed, M. W.; Avignone, F. T.; Back, H. O.; Barabash, A. S.; Boswell, M.; De Braeckeleer, L.; Brudanin, V. B.; Chan, Y.-D.; Egorov, V. G.; Elliott, S. R.; Gehman, V. M.; Hossbach, T. W.; Kephart, J. D.; Kidd, M. F.; Konovalov, S. I.; Lesko, K. T.; Li, Jingyi; Mei, D.-M.; Mikhailov, S.; Miley, H.; Radford, D. C.; Reeves, J.; Sandukovsky, V. G.; Umatov, V. I.; Underwood, T. A.; Tornow, W.; Wu, Y. K.; Young, A. R.
2014-01-01
We present data characterizing the performance of the first segmented, N-type Ge detector, isotopically enriched to 85% 76Ge. This detector, based on the Ortec PT6×2 design and referred to as SEGA (Segmented, Enriched Germanium Assembly), was developed as a possible prototype for neutrinoless double beta-decay measurements by the MAJORANA collaboration. We present some of the general characteristics (including bias potential, efficiency, leakage current, and integral cross-talk) for this detector in its temporary cryostat. We also present an analysis of the resolution of the detector, and demonstrate that for all but two segments there is at least one channel that reaches the MAJORANA resolution goal below 4 keV FWHM at 2039 keV, and all channels are below 4.5 keV FWHM.
Crosstalk corrections for improved energy resolution with highly segmented HPGe-detectors
International Nuclear Information System (INIS)
Bruyneel, Bart; Reiter, Peter; Wiens, Andreas; Eberth, Juergen; Hess, Herbert; Pascovici, Gheorghe; Warr, Nigel; Aydin, Sezgin; Bazzacco, Dino; Recchia, Francesco
2009-01-01
Crosstalk effects of 36-fold segmented, large volume AGATA HPGe detectors cause shifts in the γ-ray energy measured by the inner core and outer segments as function of segment multiplicity. The positions of the segment sum energy peaks vary approximately linearly with increasing segment multiplicity. The resolution of these peaks deteriorates also linearly as a function of segment multiplicity. Based on single event treatment, two methods were developed in the AGATA Collaboration to correct for the crosstalk induced effects by employing a linear transformation. The matrix elements are deduced from coincidence measurements of γ-rays of various energies as recorded with digital electronics. A very efficient way to determine the matrix elements is obtained by measuring the base line shifts of untriggered segments using γ-ray detection events in which energy is deposited in a single segment. A second approach is based on measuring segment energy values for γ-ray interaction events in which energy is deposited in only two segments. After performing crosstalk corrections, the investigated detector shows a good fit between the core energy and the segment sum energy at all multiplicities and an improved energy resolution of the segment sum energy peaks. The corrected core energy resolution equals the segment sum energy resolution which is superior at all folds compared to the individual uncorrected energy resolutions. This is achieved by combining the two independent energy measurements with the core contact on the one hand and the segment contacts on the other hand.
Performance of a 6x6 segmented germanium detector for {gamma}-ray tracking
Energy Technology Data Exchange (ETDEWEB)
Valiente-Dobon, J.J. E-mail: j.valiente-dobon@surrey.ac.uk; Pearson, C.J.; Regan, P.H.; Sellin, P.J.; Gelletly, W.; Morton, E.; Boston, A.; Descovich, M.; Nolan, P.J.; Simpson, J.; Lazarus, I.; Warner, D
2003-06-01
A 36 fold segmented germanium coaxial detector has been supplied by EURISYS MESURES. The outer contact is segmented both radially and longitudinally. The signals from the fast preamplifiers have been digitised by 12 bit, 40 MHz ADCs. In this article we report preliminary results obtained using this detector and their relevance for future germanium {gamma}-ray tracking arrays.
Optimization of a partially segmented block detector for MR-compatible small animal PET
International Nuclear Information System (INIS)
Hwang, Ji Yeon; Chung, Yong Hyun; Baek, Cheol-Ha; An, Su Jung; Kim, Hyun-Il; Kim, Kwang Hyun
2011-01-01
In recent years, there has been an increasing interest in the magnetic resonance (MR)-compatible positron emission tomography (PET) scanners for both clinical and preclinical practice. The aim of this study was to design a novel PET detector module using a segmented block crystal readout with an array of multi-pixel photon counters (MPPCs). A 16.5x16.5x10.0 mm 3 LSO block was segmented into an 11x11 array, and reflective material was used to fill in the cuts to optically isolate the elements. The block was attached to a 4x4 MPPC array (Hamamatsu S11064) of 3.0x3.0 mm 2 detectors to give a total effective area of 144 mm 2 . To visualize all the individual detector elements in this 11x11 detector module, the depth of the cuts was optimized by DETECT2000 simulations. The depth of the cuts determines the spread of scintillation light onto the MPPC array. The accuracy of positioning was evaluated by varying the depth of the cuts from 0.0 to 10.0 mm in steps of 0.5 mm. A spatial resolution of 1.5 mm was achieved using the optimized partially segmented block detector. The simulation results of this study can be used effectively as a guide for parameter optimization for the development of a partially segmented block detector for high-resolution MR-compatible PET scanners.
Charge Spreading and Position Sensitivity in a Segmented Planar Germanium Detector (Preprint)
National Research Council Canada - National Science Library
Kroeger, R. A; Gehrels, N; Johnson, W. N; Kurfess, J. D; Phlips, B. P; Tueller, J
1998-01-01
The size of the charge cloud collected in a segmented germanium detector is limited by the size of the initial cloud, uniformity of the electric field, and the diffusion of electrons and holes through the detector...
Gamma-ray spectroscopy with relativistic exotic heavy-ions
Indian Academy of Sciences (India)
Abstract. Feasibility of gamma-ray spectroscopy at relativistic energies with exotic heavy-ions and new generation of germanium detectors (segmented Clover) is discussed. An experiment with such detector array and radioactive is discussed.
Characterization of Compton-suppressed TIGRESS detectors for high energy gamma-rays
International Nuclear Information System (INIS)
Kshetri, R.; Andreoiu, C.; Cross, D.S.; Galinski, N.; Ball, G.C.; Djongolov, M.; Garnsworthy, A.B.; Hackman, G.; Orce, J.N.; Pearson, C.; Triambak, S.; Williams, S.J.; Drake, T.; Smalley, D.; Svensson, C.E.
2009-01-01
The TRIUMF-ISAC Gamma-Ray Escape- Suppressed Spectrometer (TIGRESS) will consist of 12 large-volume, 32-fold segmented HPGe clover detectors. Each detector is shielded by a 20-fold segmented Compton suppression shield. For performing discrete gamma-ray spectroscopy of light mass nuclei with TIGRESS, we need information about full energy peak efficiency, resolution and lineshape of full energy peaks for high energy gamma-rays. However, suitable radioactive sources having decay gamma-rays of energies greater than ∼ 3.5 MeV are not easily available. So the characteristics of gamma spectrometers at energies higher than 3.5 MeV are usually determined from simulation data. Predictions from GEANT4 simulations (experimentally validated from 0.3 to 3 MeV) indicate that TIGRESS will be capable for single 10 MeV gamma-rays of absolute detection efficiency of 1.5% for backward configuration of the array. It has been observed experimentally that simulation results work well up to certain energies and might deviate at higher energies. So, it is essential to check the validity of simulation results for energies above 3.3 MeV. We have investigated the high energy performance of seven TIGRESS detectors up to 8 MeV
Segmented quasi-coaxial HP-Ge detectors optimized for spatial localization of the events
International Nuclear Information System (INIS)
Ripamonti, Giancarlo; Pulici, Paolo; Abbiati, Roberto
2006-01-01
A methodology for the design of segmented high purity Germanium detectors is presented. Its motivation follows from the necessity of making it easier to derive fast algorithms for measuring the gamma-detector interaction position. By using our study, detector geometries can be designed, which could allow a first estimate of the interaction coordinate along the carrier drift direction by analyzing the shape of the signal of a single segment. The maximum resolution that can be achieved and the corresponding conditions for the electronics are highlighted: basic unavoidable constraints limit the resolution to around 3 mm, but this first position estimate can be used, at least in principle, as a starting point for more accurate, although computationally heavy, algorithms
Looking for anomalons with a segmented Cerenkov detector
International Nuclear Information System (INIS)
Olson, D.L.
1984-10-01
An experiment performed at the Lawrence Berkeley Laboratory Bevalac, Expt. 676H, to study the anomalon effect with a segmented total-internal-reflection Cerenkov detector is reported. Radiators of 3mm thick BK7W optical glass and 2mm thick fused silica and a beam of 40 Ca at 2.1 GeV/nucleon were used. Results are presented and discussed
White clover regenerative ability under N fertilizing and grazing
Directory of Open Access Journals (Sweden)
Josip Leto
2008-12-01
Full Text Available Recently, ecological and economic factors in milk and meat production stimulate use of legumes and grass-legumes mixtures, with zero or minimum mineral N as alternative to grass monoculture with high rate of mineral N. Research objective was to examine the effect of N application (0-N0 and 150 kg ha-1 year-1-N150 and rotational grazing by cattle (C and sheep (S on white clover: growing points number, stolon lenght, stolon dry weight, dry matter yield and clover contribution to total annual herbage production. N150 significantly reduced the growing points number, stolon length and stolon dry weight for more than 70 % compared to N0. Grazing treatment affected stolon population density only in interaction with N application because of N150 significantly reduced white clover population density only in sheep grazing. S-treatment had higher clover DM yield (0.21 t ha-1 than C-treatment (0.13 t ha-1. N0 had higher clover DM yield (0.25 t ha-1 than N150 (0.09 t ha-1. However, the interaction grazing management x N rate was significant for clover DM yield and clover contribution to total DM yield. N150 reduced both parameters for 80 % only in sheep grazing while difference in DM yield and clover contribution to total DM yield between grazing treatment was recorded only in N0 Sheep grazing increased DM yield for 150 % and clover contribution for 99 % compared to cattle grazing.
Lithium-drifted silicon detector with segmented contacts
Tindall, Craig S.; Luke, Paul N.
2006-06-13
A method and apparatus for creating both segmented and unsegmented radiation detectors which can operate at room temperature. The devices include a metal contact layer, and an n-type blocking contact formed from a thin layer of amorphous semiconductor. In one embodiment the material beneath the n-type contact is n-type material, such as lithium compensated silicon that forms the active region of the device. The active layer has been compensated to a degree at which the device may be fully depleted at low bias voltages. A p-type blocking contact layer, or a p-type donor material can be formed beneath a second metal contact layer to complete the device structure. When the contacts to the device are segmented, the device is capable of position sensitive detection and spectroscopy of ionizing radiation, such as photons, electrons, and ions.
The CARDS array for neutron-rich decay spectroscopy at HRIBF
Batchelder, J C; Bingham, C R; Carter, H K; Cole, J D; Fong, D; Garrett, P E; Grzywacz, R; Hamilton, J H; Hartley, D J; Hwang, J K; Krolas, W; Kulp, D C; Larochelle, Y; Piechaczek, A; Ramayya, A V; Rykaczewski, K; Spejewski, E H; Stracener, D W; Tantawy, M N; Winger, J A; Wood, J; Zganjar, E F
2003-01-01
An array for decay studies of neutron-rich nuclei has been commissioned for use at the UNISOR separator at Holifield Radioactive Ion Beam Facility. This array consists of three segmented clover Ge detectors, plastic scintillators, and a high-resolution (approx 1 keV) Si conversion electron spectrometer. These detectors are mounted on a support that surrounds a moving tape collector. This system has been named clover array for radioactive decay studies. The detectors have been outfitted with digital flash ADCs (XIA DGFs) that fit the preamp signals, with built-in pileup rejection.
The CARDS array for neutron-rich decay spectroscopy at HRIBF
International Nuclear Information System (INIS)
Batchelder, J.C.; Bilheux, J.-C.; Bingham, C.R.; Carter, H.K.; Cole, J.D.; Fong, D.; Garrett, P.E.; Grzywacz, R.; Hamilton, J.H.; Hartley, D.J.; Hwang, J.K.; Krolas, W.; Kulp, D.; Larochelle, Y.; Piechaczek, A.; Ramayya, A.V.; Rykaczewski, K.P.; Spejewski, E.H.; Stracener, D.W.; Tantawy, M.N.; Winger, J.A.; Wood, J.; Zganjar, E.F.
2003-01-01
An array for decay studies of neutron-rich nuclei has been commissioned for use at the UNISOR separator at Holifield Radioactive Ion Beam Facility. This array consists of three segmented clover Ge detectors, plastic scintillators, and a high-resolution (∼1 keV) Si conversion electron spectrometer. These detectors are mounted on a support that surrounds a moving tape collector. This system has been named clover array for radioactive decay studies. The detectors have been outfitted with digital flash ADCs (XIA DGFs) that fit the preamp signals, with built-in pileup rejection
Characterization of segmented large volume, high purity germanium detectors
International Nuclear Information System (INIS)
Bruyneel, B.
2006-01-01
γ-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple γ-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by γ-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics. The results are
Characterization of segmented large volume, high purity germanium detectors
Energy Technology Data Exchange (ETDEWEB)
Bruyneel, B. [Koeln Univ. (Germany). Inst. fuer Kernphysik
2006-07-01
{gamma}-ray tracking in future HPGe arrays like AGATA will rely on pulse shape analysis (PSA) of multiple {gamma}-interactions. For this purpose, a simple and fast procedure was developed which enabled the first full characterization of a segmented large volume HPGe detector. An analytical model for the hole mobility in a Ge crystal lattice was developed to describe the hole drift anisotropy with experimental velocity values along the crystal axis as parameters. The new model is based on the drifted Maxwellian hole distribution in Ge. It is verified by reproducing successfully experimental longitudinal hole anisotropy data. A comparison between electron and hole mobility shows large differences for the longitudinal and tangential velocity anisotropy as a function of the electrical field orientation. Measurements on a 12 fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by {gamma}-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60 keV. A precise measurement of the hole drift anisotropy was performed with 356 keV rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and the digital electronics
Optimization of Compton-suppression and summing schemes for the TIGRESS HPGe detector array
Schumaker, M. A.; Svensson, C. E.; Andreoiu, C.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Boston, A. J.; Chakrawarthy, R. S.; Churchman, R.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Jones, B.; Maharaj, R.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Scraggs, H. C.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.
2007-04-01
Methods of optimizing the performance of an array of Compton-suppressed, segmented HPGe clover detectors have been developed which rely on the physical position sensitivity of both the HPGe crystals and the Compton-suppression shields. These relatively simple analysis procedures promise to improve the precision of experiments with the TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS). Suppression schemes will improve the efficiency and peak-to-total ratio of TIGRESS for high γ-ray multiplicity events by taking advantage of the 20-fold segmentation of the Compton-suppression shields, while the use of different summing schemes will improve results for a wide range of experimental conditions. The benefits of these methods are compared for many γ-ray energies and multiplicities using a GEANT4 simulation, and the optimal physical configuration of the TIGRESS array under each set of conditions is determined.
Effect of SiO$_{2}$ passivating layer in segmented silicon planar detectors on the detector response
Verbitskaya, Elena; Eremin, Vladimir; Golubkov, S; Konkov, K; Roe, Shaun; Ruggiero, G; Sidorov, A; Weilhammer, Peter
2004-01-01
Silicon detectors with a fine segmentation (micropixel and microstrip) are the main type of detectors used in the inner trackers of LHC experiments. Due to the high luminosity of the LHC machines they are required to have a fast response to fit the short shaping time of 25 ns and to be radiation hard. Evaluation of silicon microstrip detectors developed for the ATLAS silicon tracker and carried out under collaboration of CERN and PTI has shown the reversal of the pulse polarity in the detector response to short- range radiation. Since the negative signal is of about 30% of the normal positive one, the effect strongly reduces the charge collection efficiency in irradiated detectors. The investigation presents the consideration on the origin of a negative response in Si microstrip detectors and the experimental proof of the model. The study of the effect has been carried out using "baby" strip detectors with a special design: each strip has a window in a metallization, which covers the p/sup +/ implant. The sca...
Development of a hadron blind detector using a finely segmented pad readout
International Nuclear Information System (INIS)
Kanno, Koki; Aoki, Kazuya; Aramaki, Yoki; En'yo, Hideto; Kawama, Daisuke; Komatsu, Yusuke; Masumoto, Shinichi; Nakai, Wataru; Obara, Yuki; Ozawa, Kyoichiro; Sekimoto, Michiko; Shibukawa, Takuya; Takahashi, Tomonori; Watanabe, Yosuke; Yokkaichi, Satoshi
2016-01-01
We constructed a hadron blind detector (HBD) using a finely segmented pad readout. The finely segmented pad readout enabled us to adopt an advanced particle identification method which applies a threshold to the number of pad hits in addition to the total amount of collected charge. The responses of the detector to electrons and pions were evaluated using a negatively charged secondary beam at 1.0 GeV/c containing 20% electrons at the J-PARC K1.1BR beam line. We observed 7.3 photoelectrons per incident electron. Using the advanced particle identification method, an electron detection efficiency of 83% was achieved with a pion rejection factor of 120. The method improved the pion rejection by approximately a factor of five, compared to the one which just applies a threshold to the amount of collected charge. The newly introduced finely segmented pad readout was found to be effective in rejecting pions.
Development of a hadron blind detector using a finely segmented pad readout
Energy Technology Data Exchange (ETDEWEB)
Kanno, Koki, E-mail: kkanno@post.kek.jp [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aoki, Kazuya [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Aramaki, Yoki; En' yo, Hideto; Kawama, Daisuke [RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Komatsu, Yusuke; Masumoto, Shinichi [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Nakai, Wataru [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Obara, Yuki [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ozawa, Kyoichiro; Sekimoto, Michiko [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Shibukawa, Takuya [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Takahashi, Tomonori [Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Watanabe, Yosuke [Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yokkaichi, Satoshi [RIKEN Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
2016-05-21
We constructed a hadron blind detector (HBD) using a finely segmented pad readout. The finely segmented pad readout enabled us to adopt an advanced particle identification method which applies a threshold to the number of pad hits in addition to the total amount of collected charge. The responses of the detector to electrons and pions were evaluated using a negatively charged secondary beam at 1.0 GeV/c containing 20% electrons at the J-PARC K1.1BR beam line. We observed 7.3 photoelectrons per incident electron. Using the advanced particle identification method, an electron detection efficiency of 83% was achieved with a pion rejection factor of 120. The method improved the pion rejection by approximately a factor of five, compared to the one which just applies a threshold to the amount of collected charge. The newly introduced finely segmented pad readout was found to be effective in rejecting pions.
Mohammadi, Akram; Inadama, Naoko; Yoshida, Eiji; Nishikido, Fumihiko; Shimizu, Keiji; Yamaya, Taiga
2017-09-01
We have developed a four-layer depth of interaction (DOI) detector with single-side photon readout, in which segmented crystals with the patterned reflector insertion are separately identified by the Anger-type calculation. Optical conditions between segmented crystals, where there is no reflector, affect crystal identification ability. Our objective of this work was to improve crystal identification performance of the four-layer DOI detector that uses crystals segmented with a recently developed laser processing technique to include laser processed boundaries (LPBs). The detector consisted of 2 × 2 × 4mm3 LYSO crystals and a 4 × 4 array multianode photomultiplier tube (PMT) with 4.5 mm anode pitch. The 2D position map of the detector was calculated by the Anger calculation method. At first, influence of optical condition on crystal identification was evaluated for a one-layer detector consisting of a 2 × 2 crystal array with three different optical conditions between the crystals: crystals stuck together using room temperature vulcanized (RTV) rubber, crystals with air coupling and segmented crystals with LPBs. The crystal array with LPBs gave the shortest distance between crystal responses in the 2D position map compared with the crystal array coupled with RTV rubber or air due to the great amount of cross-talk between segmented crystals with LPBs. These results were used to find optical conditions offering the optimum distance between crystal responses in the 2D position map for the four-layer DOI detector. Crystal identification performance for the four-layer DOI detector consisting of an 8 × 8 array of crystals segmented with LPBs was examined and it was not acceptable for the crystals in the first layer. The crystal identification was improved for the first layer by changing the optical conditions between all 2 × 2 crystal arrays of the first layer to RTV coupling. More improvement was observed by combining different optical conditions between all
Charge collection performance of a segmented planar high-purity germanium detector
Energy Technology Data Exchange (ETDEWEB)
Cooper, R.J. [Department of Physics, The University of Liverpool, Oliver Lodge Laboratory, Liverpool Merseyside L69 7ZE (United Kingdom)], E-mail: R.Cooper@liverpool.ac.uk; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Grint, A.N.; Harkness, L.J.; Nolan, P.J.; Oxley, D.C.; Scraggs, D.P. [Department of Physics, The University of Liverpool, Oliver Lodge Laboratory, Liverpool Merseyside L69 7ZE (United Kingdom); Lazarus, I.; Simpson, J. [STFC Daresbury Laboratory, Warrington, Cheshire WA4 4AD (United Kingdom); Dobson, J. [Rosemere Cancer Centre, Royal Preston Hospital, Preston PR2 9HT (United Kingdom)
2008-10-01
High-precision scans of a segmented planar high-purity germanium (HPGe) detector have been performed with a range of finely collimated gamma ray beams allowing the response as a function of gamma ray interaction position to be quantified. This has allowed the development of parametric pulse shape analysis (PSA) techniques and algorithms for the correction of imperfections in performance. In this paper we report on the performance of this detector, designed for use in a positron emission tomography (PET) development system.
Multichannel prototype of coordinate detector based on segmented straws
International Nuclear Information System (INIS)
Gusakov, Yu.V.; Davkov, V.I.; Davkov, K.I.; Zhukov, I.A.; Lutsenko, V.M.; Myalkovskij, V.V.; Peshekhonov, V.D.; Savenkov, A.A.
2010-01-01
The design and assembly technology of a detector prototype based on segmented straws is considered. The granularity of the prototype is 4 cm 2 . The prototype has a sensitive area of 400 x 200 mm, and contains two straw planes displaced against each other by 2 mm. The number of registration channels is 360. Preliminary results of the bench study of the prototype are presented
International Nuclear Information System (INIS)
Choi, T.; Jung, Y.S.
2006-01-01
Full text: Full text: Korean Standard Nuclear Plant uses Self Powered Neutron Detectors (SPNDs) to measure the neutron flux in the reactor core. The SPND's height is 40 cm and is located axially at the five different positions and 45 radial places. The design code simulated a reactor core is calculated by segmentation of the core. The segmentation is called as 'node', of which size is normally 20 cm. The axial height of the detector is larger than that of the node, and the larger detector's height maybe product some error on the axially complex shape. The analysis with the detector's signals showed some errors at the non-cosine axial flux shape. In order to reduce the errors for the shape, we tried to divide the detector by introducing the virtual boundary in the detector. Then, each axially 5 detectors had two virtual segmentations respectively and the detector's signal was divided by the inputs. So the more virtual detector's signals were gotten, the more accurate axial shape was produced. The result with virtual segmentations in a detector gave less deviation than the case without virtual segmentation (the current model). After the middle of cycle at the initial core specially, the axial neutron flux shape is changed to the saddle type one. The current model gave some error in Root Mean Square (RMS) between the measured value and the calculated one. The virtual segmentation model gave the better agreement at that time
International Nuclear Information System (INIS)
Han, L.
1995-05-01
The aim of this thesis is the development of new types of germanium detectors: the composite detectors. Two types of prototypes are then conceived: the stacked planar detector (EDP) and the assembly of coaxial diodes (TREFLE). They are designed for the multidetector EUROGAM destined to the research of nuclear structure at high angular momentum. The four planar diodes of EDP detector were of 7 cm diameter and of 15 to 20 mm thick. The difference between the calculated and measured photopic efficiency is observed. The importance of surface channel induces a weak resistance of neutron damages. The sputtering method for the surface treatment reducing the germanium dead layer as well as a rule of selection concerning the impurity concentration and the thickness of crystal is helpful for the later production of germanium detector. The CLOVER detector consist of for mean size crystals in the same cryostat. The photopic efficiency is much larger than that of the greatest monocrystal detector. And the granulation of composite detector allowed the Doppler broadening correction of gamma ray observed in the nuclear reaction where the recoil velocity is very high. This new type of detector enable the linear polarization measurement of gamma ray. Twenty-four CLOVER detector are actually mounted in the EUROGAM array. The characteristics measured in source as well as in beam, reported in this thesis, meet exactly the charge account. (author). 47 refs., 61 figs., 18 tabs
DEFF Research Database (Denmark)
Eriksen, Jørgen; Askegaard, Margrethe; Søegaard, Karen
2014-01-01
Increasing plant species diversity in grasslands may improve productivity and stability of yields. In a field experiment, we investigated the herbage dry-matter (DM) yield and crude protein content of two-species swards of perennial ryegrass–white clover (Lolium perenne L.–Trifolium repens L...... clover in sown swards are discussed. These may include higher nitrogen-use efficiency in ruminants, increased soil fertility and improved sward flexibility to cope with changing managements. The findings also suggest positive yield effects of alternating between cutting and grazing within the season...
Segmented detector for recoil neutrons in the p(γ, n)π+ reaction
International Nuclear Information System (INIS)
Korkmaz, E.; O'Rielly, G.V.; Hutcheon, D.A.; Feldman, G.; Jordan, D.; Kolb, N.R.; Pywell, R.E.; Retzlaff, G.A.; Sawatzky, B.D.; Skopik, D.M.; Vogt, J.M.; Cairns, E.; Giesen, U.; Holm, L.; Opper, A.K.; Rozon, F.M.; Soukup, J.
1999-01-01
A segmented neutron detector has been constructed and used for recoil neutron (6-13 MeV) measurements of the reaction γp→nπ + very close to threshold. BC-505 liquid scintillator was used to allow pulse shape discrimination between neutrons and photons. A measurement of the absolute efficiency of the detector was performed using stopped pions in the reaction π - p→nγ. Results of the efficiency calibration are compared to a Monte Carlo simulation. (author)
Non-perturbative improvement of stout-smeared three flavour clover fermions
Energy Technology Data Exchange (ETDEWEB)
Cundy, N.; Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, R. [Edinburgh Univ. (GB). School of Physics and Astronomy] (and others)
2009-01-15
We discuss a 3-flavour lattice QCD action with clover improvement in which the fermion matrix has single level stout smearing for the hopping terms together with unsmeared links for the clover term. With the (tree-level) Symanzik improved gluon action this constitutes the Stout Link Non-perturbative Clover or SLiNC action. To cancel O(a) terms the clover term coefficient has to be tuned. We present here results of a non-perturbative determination of this coefficient using the Schroedinger functional and as a by-product a determination of the critical hopping parameter. Comparisons of the results are made with lowest order perturbation theory. (orig.)
Impact on Clover-Grass Yield from Wheel Load and Tyre Pressure
DEFF Research Database (Denmark)
Green, Ole; Jørgensen, Rasmus Nyholm; Sørensen, Claus Aage Grøn
2009-01-01
Traffic intensities have been shown to have a negative influence on the yield of grass and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16 different traffi...
Sources of N2O in organic grass-clover pastures
Ambus, P.
2002-01-01
Organic farming practises, and in particular dairy production systems based on grass-clover pastures are becoming increasingly abundant within Danish agriculture. Grass-clover pastures may provide a mitigation option to reduce grassland nitrous oxide (N2O) emissions (Velthof et al. 1998). The objectives of this work was to examine the relationship between N2O emissions and transformations of inorganic N in organically managed grass-clover pastures of different ages. Results from the projec...
Application of various technological processes in red clover seed processing
Đokić, Dragoslav; Stanisavljević, Rade; Terzić, Dragan; Marković, Jordan; Radivojević, Gordana; Anđelković, Bojan; Barać, Saša
2012-01-01
This paper presents the results of the processing of natural red clover seed on the processing equipment using different technological methods. Red clover seed, for the establishment and crop utilization, must be of high purity, germination, and high genetic values. These requirements are achieved by processing, or removing impurities and poor quality seeds. Red clover seed processing involves a number of operations, of which the most important are: cleaning, packaging, labeling and storage. ...
Specific activity isolation and determination of radioactive Estrogenic Substances in White Clover
International Nuclear Information System (INIS)
Pupiales T, G.; Mejia M, G.
1986-01-01
Due to high number of leguminous that exhibit estrogenic activity, subterranean clover between others, which causes infertility in sheep that eat it. It has been considered that white clover (Trifolium repens, variety Ladino, is an specie of low estrogenic activity, however at Bogota City (Colombia) it has high estrogenic activity and may cause reduction in the dairy cattle fertility. Research done in the IAN (today Ingeominas) over this clover variety, showed that the radioactivity substances presents in the white clover have high activity for stradiol, affecting organs from mouse females; Isoflavonoids from vegetables have an anabolism and utero tropic action; estrogenic activity of clover leaves, was exponentially proportional to the amount of ultraviolet radioactivity, falling upon plants during leaves development stage
TIGRESS: TRIUMF-ISAC gamma-ray escape-suppressed spectrometer
Svensson, C. E.; Amaudruz, P.; Andreoiu, C.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Boston, A. J.; Chakrawarthy, R. S.; Chen, A. A.; Churchman, R.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Jones, B.; Kanungo, R.; Maharaj, R.; Martin, J. P.; Morris, D.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Roy, R.; Sarazin, F.; Schumaker, M. A.; Scraggs, H. C.; Smith, M. B.; Starinsky, N.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.
2005-10-01
The TRIUMF-ISAC gamma-ray escape-suppressed spectrometer (TIGRESS) is a new γ-ray detector array being developed for use at TRIUMF's Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. TIGRESS will comprise 12 32-fold segmented clover-type HPGe detectors coupled with 20-fold segmented modular Compton suppression shields and custom digital signal processing electronics. This paper provides an overview of the TIGRESS project and progress in its development to date.
Fate in Soil of Flavonoids Released from White Clover (Trifolium repens L.)
DEFF Research Database (Denmark)
Carlsen, Sandra C. K.; Pedersen, Hans A.; Spliid, Niels H.
2012-01-01
the presence in soil of bioactive secondary metabolites from clover has received limited attention. In this paper we examine for the first time the release of flavonoids both from field-grown white clover and from soil-incorporated white clover plants of flavonoids, as analyzed by LC-MS/MS. The dominant...... flavonoid aglycones were formononetin, medicarpin, and kaempferol. Soil-incorporated white clover plants generated high concentrations of the glycosides kaempferol-Rha-Xyl-Gal and quercetin-Xyl-Gal. Substantial amounts of kaempferol persisted in the soil for days while the other compounds were degraded...
Reduction in clover-grass yield caused by different traffic intensities
DEFF Research Database (Denmark)
Green, Ole; Jørgensen, Rasmus Nyholm; Kristensen, Kristian
Different traffic intensities have been shown to have a negative influence on the yield of grass and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16...... close to the north, south and east border of the field. No significant interactions were found between the timing of crop and soil damage as affected by wheel load and tire pressure. However, at specific times, there was a significant effect of wheel load and secondary by the tire pressure. At all...... measurement times, the yield was lower using a wheel load of 4745 kg than for a wheel load of 2865 kg. Key words (for Electronic Reference Library) Traffic intensities, tire load/pressure, clover/grass, yield loss, ...
Evaluation of Segmented Amorphous-Contact Planar Germanium Detectors for Heavy-Element Research
Jackson, Emily G.
The challenge of improving our understanding of the very heaviest nuclei is at the forefront of contemporary low-energy nuclear physics. In the last two decades, "in-beam" spectroscopy experiments have advanced from Z=98 to Z=104, Rutherfordium, allowing insights into the dynamics of the fission barrier, high-order deformations, and pairing correlations. However, new detector technologies are needed to advance to even heavier nuclei. This dissertation is aimed at evaluating one promising new technology; large segmented planar germanium wafers for this area of research. The current frontier in gamma-ray spectroscopy involves large-volume (>9 cm thick) coaxial detectors that are position sensitive and employ gamma-ray "tracking". In contrast, the detectors assessed in this dissertation are relatively thin (~1 cm) segmented planar wafers with amorphous-germanium strip contacts that can tolerate extremely high gamma-ray count rates, and can accommodate hostile neutron fluxes. They may be the only path to heavier "in-beam" spectroscopy with production rates below 1 nanobarn. The resiliency of these detectors against neutron-induced damage is examined. Two detectors were deliberately subjected to a non-uniform neutron fluence leading to considerable degradation of performance. The neutrons were produced using the 7Li(p, n)7Be reaction at the UMass Lowell Van-de-Graaff accelerator with a 3.7-MeV proton beam incident on a natural Li target. The energy of the neutrons emitted at zero degrees was 2.0 MeV, close to the mean energy of the fission neutron spectrum, and each detector was exposed to a fluence >3.6 x109 n/cm2. A 3-D software "trap-corrector" gain-matching algorithm considerably restored the overall performance. Other neutron damage mitigation tactics were explored including over biasing the detector and flooding the detector with a high gamma-ray count rate. Various annealing processes to remove neutron damage were investigated. An array of very large diameter
Segment-Tube: Spatio-Temporal Action Localization in Untrimmed Videos with Per-Frame Segmentation
Le Wang; Xuhuan Duan; Qilin Zhang; Zhenxing Niu; Gang Hua; Nanning Zheng
2018-01-01
Inspired by the recent spatio-temporal action localization efforts with tubelets (sequences of bounding boxes), we present a new spatio-temporal action localization detector Segment-tube, which consists of sequences of per-frame segmentation masks. The proposed Segment-tube detector can temporally pinpoint the starting/ending frame of each action category in the presence of preceding/subsequent interference actions in untrimmed videos. Simultaneously, the Segment-tube detector produces per-fr...
Clover, Red (Trifolium pretense)
Genetic modification of plants by the insertion of transgenes can be a powerful experimental approach to answer basic questions about gene product function. This technology can also be used to make improved crop varieties for use in the field. To apply this powerful tool to red clover, an important ...
Estimating grass-clover ratio variations caused by traffic intensities using image analysis
DEFF Research Database (Denmark)
Jørgensen, Rasmus Nyholm; Sørensen, Claus Grøn; Green, Ole
Grass and especially clover have a negative yield response as a function of traffic intensity. Conventional grass-clover production for silage have high traffic intensity due to fertilizing with slurry, cutting the grass, rolling the grass into swaths, and collecting and chopping the grass...... to fulfill the aim [1]http://www.ruralni.gov.uk/index/publications/press_articles/dairy-2/role-of-clover.htm...
The Edge Detectors Suitable for Retinal OCT Image Segmentation
Directory of Open Access Journals (Sweden)
Su Luo
2017-01-01
Full Text Available Retinal layer thickness measurement offers important information for reliable diagnosis of retinal diseases and for the evaluation of disease development and medical treatment responses. This task critically depends on the accurate edge detection of the retinal layers in OCT images. Here, we intended to search for the most suitable edge detectors for the retinal OCT image segmentation task. The three most promising edge detection algorithms were identified in the related literature: Canny edge detector, the two-pass method, and the EdgeFlow technique. The quantitative evaluation results show that the two-pass method outperforms consistently the Canny detector and the EdgeFlow technique in delineating the retinal layer boundaries in the OCT images. In addition, the mean localization deviation metrics show that the two-pass method caused the smallest edge shifting problem. These findings suggest that the two-pass method is the best among the three algorithms for detecting retinal layer boundaries. The overall better performance of Canny and two-pass methods over EdgeFlow technique implies that the OCT images contain more intensity gradient information than texture changes along the retinal layer boundaries. The results will guide our future efforts in the quantitative analysis of retinal OCT images for the effective use of OCT technologies in the field of ophthalmology.
In situ carbon and nitrogen dynamics in ryegrass-clover mixtures
DEFF Research Database (Denmark)
Rasmussen, J.; Eriksen, J.; Jensen, Erik Steen
2007-01-01
=9). 15N-enriched compounds were not detected in percolating pore water, which may be caused by either dilution from irrigation or low availability of leachable N compounds. 14C was found solely as 14CO2 in the pore water indicating that dissolved organic carbon (DOC) did not originate from fresh......Carbon (C) and nitrogen (N) dynamics in a third production year ryegrass–clover mixture were investigated in the field. Cylinders (diameter 29.7 cm) were installed to depths of 20, 40 and 60 cm and equipped with suction cups to collect percolating pore water. Ryegrass and clover leaves were cross......-labelled with 14C- and 15N-enriched urea and the fate of the two tracers was studied for 3 months during summer. Transfer of 14C occurred mainly from ryegrass to clover, whereas the largest transfer of 15N was in the opposite direction. The average transfer of N from clover was 40% (SE±3.1, n=9) of N in ryegrass...
Potential for yield in red clover (Trifolium pratense L. varieties
Directory of Open Access Journals (Sweden)
Vasiljević Sanja
2010-01-01
Full Text Available Red clover (Trifolium pratense L. is botanically a perennial, although it often behaves as a biennial. The crop usually lives 2 to 3 seasons in most clover-growing regions of the world and is generally conceded to be lacking in persistence. The objective of this investigation was to analyze the production potential and persistence of domestic and imported red clover varieties. Experiments were conducted at Rimski Šančevi Experiment Field during the period 2004-2006. The experimental materials were six varieties (K-17, Kolubara, Una, Viola, Start, Nike which were analyzed for the most important production characteristics: yield of green mass, dry matter yield and persistence. .
Simulation and real-time analysis of pulse shapes from segmented HPGe-detectors
Energy Technology Data Exchange (ETDEWEB)
Schlarb, Michael Christian
2009-11-17
The capabilities of future HPGe arrays consisting of highly segmented detectors, like AGATA will depend heavily on the performance of {gamma}-ray tracking. The most crucial component in the whole concept is the pulse shape analysis (PSA). The working principle of PSA is to compare the experimental signal shape with signals available from a basis set with known interaction locations. The efficiency of the tracking algorithm hinges on the ability of the PSA to reconstruct the interaction locations accurately, especially for multiple {gamma}-interactions. Given the size of the arrays the PSA algorithm must be run in a real-time environment. A prerequisite to a successful PSA is an accurate knowledge of the detectors response. Making a full coincidence scan of a single AGATA detector, however takes between two and three months, which is too long to produce an experimental signal basis for all detector elements. A straight forward possibility is to use a precise simulation of the detector and to provide a basis of simulated signals. For this purpose the Java Agata Signal Simulation (JASS) was developed in the course of this thesis. The geometry of the detector is given with numerical precision and models describing the anisotropic mobilities of the charge carriers in germanium were taken from the literature. The pulse shapes of the transient and net-charge signals are calculated using weighting potentials on a finite grid. Special care was taken that the interpolation routine not only reproduces the weighting potentials precisely in the highly varying areas of the segment boundaries but also that its performance is independent of the location within the detector. Finally data from a coincidence scan and a pencil beam experiment were used to verify JASS. The experimental signals are reproduced accurately by the simulation. Pulse Shape Analysis (PSA) reconstructs the positions of the individual interactions and the corresponding energy deposits within the detector. This
Simulation and real-time analysis of pulse shapes from segmented HPGe-detectors
International Nuclear Information System (INIS)
Schlarb, Michael Christian
2009-01-01
The capabilities of future HPGe arrays consisting of highly segmented detectors, like AGATA will depend heavily on the performance of γ-ray tracking. The most crucial component in the whole concept is the pulse shape analysis (PSA). The working principle of PSA is to compare the experimental signal shape with signals available from a basis set with known interaction locations. The efficiency of the tracking algorithm hinges on the ability of the PSA to reconstruct the interaction locations accurately, especially for multiple γ-interactions. Given the size of the arrays the PSA algorithm must be run in a real-time environment. A prerequisite to a successful PSA is an accurate knowledge of the detectors response. Making a full coincidence scan of a single AGATA detector, however takes between two and three months, which is too long to produce an experimental signal basis for all detector elements. A straight forward possibility is to use a precise simulation of the detector and to provide a basis of simulated signals. For this purpose the Java Agata Signal Simulation (JASS) was developed in the course of this thesis. The geometry of the detector is given with numerical precision and models describing the anisotropic mobilities of the charge carriers in germanium were taken from the literature. The pulse shapes of the transient and net-charge signals are calculated using weighting potentials on a finite grid. Special care was taken that the interpolation routine not only reproduces the weighting potentials precisely in the highly varying areas of the segment boundaries but also that its performance is independent of the location within the detector. Finally data from a coincidence scan and a pencil beam experiment were used to verify JASS. The experimental signals are reproduced accurately by the simulation. Pulse Shape Analysis (PSA) reconstructs the positions of the individual interactions and the corresponding energy deposits within the detector. This is
Leaching of cyanogenic glucosides and cyanide from white clover green manure
DEFF Research Database (Denmark)
Bjarnholt, Nanna; Lægdsmand, Mette; Hansen, Hans Chr. Bruun
2008-01-01
Use of crops for green manure as a substitute for chemical fertilizers and pesticides is an important approach towards more sustainable agricultural practices. Green manure from white clover is rich in nitrogen but white clover also produces the cyanogenic glucosides (CGs) linamarin...... and lotaustralin; CGs release toxic hydrogen cyanide (HCN) upon hydrolysis which may be utilized for pest control. We demonstrate that applying CGs in the form of a liquid extract of white clover to large columns of intact agricultural soils can result in leaching of toxic cyanide species to a depth of at least 1...
Decay spectroscopy of neutron-rich nuclei with the CAITEN detector
Energy Technology Data Exchange (ETDEWEB)
Steiger, Konrad [Physik-Department E12, Technische Universitaet Muenchen (Germany); Collaboration: CAITEN-Collaboration
2012-07-01
An experiment in fall 2010 at the RIBF (Radioactive Ion Beam Factory at RIKEN, Japan) investigated the neutron-rich nuclei in the neighborhood of {sup 30}Ne and {sup 36}Mg. These nuclei were produced by relativistic projectile fragmentation of a 345 AMeV {sup 48}Ca primary beam which was delivered from the superconducting ring cyclotron SRC with an average intensity of 70 pnA. The secondary cocktail beam was separated and identified with the BigRIPS fragment separator and the ZeroDegree spectrometer. The unambiguous particle identification was achieved by measuring the energy loss, time of flight and magnetic rigidity event-by-event. The identified fragments were implanted in the CAITEN detector (Cylindrical Active Implantation Target for Efficient Nuclear-decay study). The main part of this detector is a 4 x 10{sup 4}-fold segmented plastic scintillator with the shape of a hollow cylinder. To reduce background events the scintillator was moved continuously in axial and vertical direction (similar to a tape-transporting system). Implantations and decays were correlated in time and space. {gamma}-rays were detected with three germanium clover detectors. For the first time {beta}-delayed gammas were measured in the neutron-rich isotopes {sup 36-38}Si. The status of the analysis and preliminary results including new half-life values and tentative level schemes for these very exotic nuclei are presented.
International Nuclear Information System (INIS)
Schwarzhuber, Felix; Melzl, Peter; Zweck, Josef
2017-01-01
Highlights: • Practical guide to calibrate a DPC setup considering geometrical parameters. • Optimizing the field sensitivity of a segmented annular DPC detector. • Determination of maximum electric and magnetic field sensitivity of a DPC setup. - Abstract: Differential phase contrast microscopy measures minute deflections of the electron probe due to electric and/or magnetic fields, using a position sensitive device. Although recently, pixelated detectors have become available which also serve as a position sensitive device, the most frequently used detector is a four-segmented annular semiconducting detector ring (or variations thereof), where the difference signals of opposing detector elements represent the components of the deflection vector. This deflection vector can be used directly to quantitatively determine the deflecting field, provided the specimen’s thickness is known. While there exist many measurements of both electric and magnetic fields, even at an atomic level, until now the question of the smallest clearly resolvable field value for this detector has not yet been answered. This paper treats the problem theoretically first, leading to a calibration factor κ which depends solely on simple, experimentally accessible parameters and relates the deflecting field to the measured deflection vector. In a second step, the calibration factor for our combination of microscope and detector is determined experimentally for various combinations of camera length, condenser aperture and spot size to determine the optimum setup. From this optimized condition we determine the minimum change in field which leads to a clearly measurable signal change for both HMSTEM and LMSTEM operation. A strategy is described which allows the experimenter to choose the setup giving the highest field sensitivity. Quantification problems due to scattering processes in the specimen are addressed and ways are shown to choose a setup which is less sensitive to these artefacts.
Energy Technology Data Exchange (ETDEWEB)
Schwarzhuber, Felix, E-mail: felix.schwarzhuber@ur.de; Melzl, Peter; Zweck, Josef
2017-06-15
Highlights: • Practical guide to calibrate a DPC setup considering geometrical parameters. • Optimizing the field sensitivity of a segmented annular DPC detector. • Determination of maximum electric and magnetic field sensitivity of a DPC setup. - Abstract: Differential phase contrast microscopy measures minute deflections of the electron probe due to electric and/or magnetic fields, using a position sensitive device. Although recently, pixelated detectors have become available which also serve as a position sensitive device, the most frequently used detector is a four-segmented annular semiconducting detector ring (or variations thereof), where the difference signals of opposing detector elements represent the components of the deflection vector. This deflection vector can be used directly to quantitatively determine the deflecting field, provided the specimen’s thickness is known. While there exist many measurements of both electric and magnetic fields, even at an atomic level, until now the question of the smallest clearly resolvable field value for this detector has not yet been answered. This paper treats the problem theoretically first, leading to a calibration factor κ which depends solely on simple, experimentally accessible parameters and relates the deflecting field to the measured deflection vector. In a second step, the calibration factor for our combination of microscope and detector is determined experimentally for various combinations of camera length, condenser aperture and spot size to determine the optimum setup. From this optimized condition we determine the minimum change in field which leads to a clearly measurable signal change for both HMSTEM and LMSTEM operation. A strategy is described which allows the experimenter to choose the setup giving the highest field sensitivity. Quantification problems due to scattering processes in the specimen are addressed and ways are shown to choose a setup which is less sensitive to these artefacts.
International Nuclear Information System (INIS)
Abt, I.; Caldwell, A.; Gutknecht, D.; Kroeninger, K.; Lampert, M.; Liu, X.; Majorovits, B.; Quirion, D.; Stelzer, F.; Wendling, P.
2007-01-01
The first true coaxial 18-fold segmented n-type HPGe prototype detector produced by Canberra-France for the GERDA neutrinoless double beta-decay project was tested both at Canberra-France and at the Max-Planck-Institut fur Physik in Munich. The main characteristics of the detector are given and measurements concerning detector properties are described. A novel method to establish contacts between the crystal and a Kapton cable is presented
Estimating the content of clover and grass in the sward using a consumer camera and image processing
DEFF Research Database (Denmark)
Mortensen, Anders Krogh; Karstoft, Henrik; Søegaard, Karen
the dry matter ratio of clover and grass in clover grass fields from sparse close up images. First, the light conditions is determined, which is used for selecting model parameters to estimate the coverage of both clover and grass. Next, the clover and grass coverage are transformed to give the dry matter...
Cumulative effects of white clover residues on the changes in soil ...
African Journals Online (AJOL)
White clover grows naturally all over the Himalayan regions including the hilly areas of the state of Azad Jammu and Kashmir (AJK), Pakistan. This study was conducted to investigate the effects of white clover residues alone or in combination with phosphorus (P) fertilizer on maize (Zea mays L.) yield, nutrient uptake and ...
DEFF Research Database (Denmark)
Gravesen, Eigil Vestergaard
2008-01-01
Linyphiid web densities in wheat-clover bi-crop systems where winter wheat was grown in an under-storey of white clover were compared with web densities estimated in conventional wheat-growing systems. The web densities in the wheat-clover bi-crop systems were on average between 200 and 250 webs ...
Chesi, Enrico Guido; Joram, C; Mathot, S; Séguinot, Jacques; Weilhammer, P; Ciocia, F; De Leo, R; Nappi, E; Vilardi, I; Argentieri, A; Corsi, F; Dragone, A; Pasqua, D
2006-01-01
We describe the design, fabrication and test results of a segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics. Both the photodetector and its VLSI readout electronics are custom designed and have been tailored to the requirements of a recently proposed novel geometrical concept of a Positron Emission Tomograph. Emphasis is put on the PET specific features of the device. The detector has been fabricated in the photocathode facility at CERN.
International Nuclear Information System (INIS)
Carlson, R.W.
1981-01-01
A radiation detector or detector array which has a non-constant spatial response, is disclosed individually and in combination with a tomographic scanner. The detector has a first dimension which is oriented parallel to the plane of the scan circle in the scanner. Along the first dimension, the detector is most responsive to radiation received along a centered segment of the dimension and less responsive to radiation received along edge segments. This non-constant spatial response can be achieved in a detector comprised of a scintillation crystal and a photoelectric transducer. The scintillation crystal in one embodiment is composed of three crystals arranged in layers, with the center crystal having the greatest light conversion efficiency. In another embodiment, the crystal is covered with a reflective substance around the center segment and a less reflective substance around the remainder. In another embodiment, an optical coupling which transmits light from adjacent the center segment with the greatest intensity couples the scintillation crystal and the photoelectric transducer. In yet another embodiment, the photoelectric transducer comprises three photodiodes, one receiving light produced adjacent the central segment and the other two receiving light produced adjacent the edge segments. The outputs of the three photodiodes are combined with a differential amplifier
In-beam measurement of the position resolution of a highly segmented coaxial germanium detector
International Nuclear Information System (INIS)
Descovich, M.; Lee, I.Y.; Fallon, P.; Cromaz, M.; Macchiavelli, A.O.; Radford, D.C.; Vetter, K.; Clark, R.M.; Deleplanque, M.A.; Stephens, F.S.; Ward, D.
2005-01-01
The position resolution of a highly segmented coaxial germanium detector was determined by analyzing the 2055keV γ-ray transition of Zr90 excited in a fusion-evaporation reaction. The high velocity of the Zr90 nuclei imparted large Doppler shifts. Digital analysis of the detector signals recovered the energy and position of individual γ-ray interactions. The location of the first interaction in the crystal was used to correct the Doppler energy shift. Comparison of the measured energy resolution with simulations implied a position resolution (root mean square) of 2mm in three-dimensions
Directory of Open Access Journals (Sweden)
Mark Richard McNeill
2016-09-01
Full Text Available To determine if host plant abundance determined the size of clover root weevil (CRW Sitona obsoletus larval populations, a study was conducted over four years in plots sown in ryegrass (Lolium perenne (cv. Nui sown at either 6 or 30 kg/ha and white clover (Trifolium repens sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand with % clover measured in autumn (April and spring (September of each year. Overall, mean larval densities measured in spring 2012, 2013, 2014 and 2015 were 310, 38, 59 and 31 larvae m-2, respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3 and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October larval populations to % white clover measured in each plot in autumn (April found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted
McNeill, Mark R; van Koten, Chikako; Cave, Vanessa M; Chapman, David; Hodgson, Hamish
2016-01-01
To determine if host plant abundance determined the size of clover root weevil (CRW) Sitona obsoletus larval populations, a study was conducted over 4 years in plots sown in ryegrass ( Lolium perenne ) (cv. Nui) sown at either 6 or 30 kg/ha and white clover ( Trifolium repens ) sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October) when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand) with % clover measured in autumn (April) and spring (September) of each year. Overall, mean larval densities measured in spring 2012-2015 were 310, 38, 59, and 31 larvae m -2 , respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3, and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October) larval populations to % white clover measured in each plot in autumn (April) found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted, but the numbers
Steen, Kim Arild; Green, Ole; Karstoft, Henrik
2017-01-01
Optimal fertilization of clover-grass fields relies on knowledge of the clover and grass fractions. This study shows how knowledge can be obtained by analyzing images collected in fields automatically. A fully convolutional neural network was trained to create a pixel-wise classification of clover, grass, and weeds in red, green, and blue (RGB) images of clover-grass mixtures. The estimated clover fractions of the dry matter from the images were found to be highly correlated with the real clover fractions of the dry matter, making this a cheap and non-destructive way of monitoring clover-grass fields. The network was trained solely on simulated top-down images of clover-grass fields. This enables the network to distinguish clover, grass, and weed pixels in real images. The use of simulated images for training reduces the manual labor to a few hours, as compared to more than 3000 h when all the real images are annotated for training. The network was tested on images with varied clover/grass ratios and achieved an overall pixel classification accuracy of 83.4%, while estimating the dry matter clover fraction with a standard deviation of 7.8%. PMID:29258215
Shahbaz, Ali Khan; Iqbal, Muhammad; Jabbar, Abdul; Hussain, Sabir; Ibrahim, Muhammad
2018-03-01
Application of immobilizing agents may efficiently reduce the bioavailability of nickel (Ni) in the soil. Here we report the effect of biochar (BC), gravel sludge (GS) and zeolite (ZE) as a sole treatment and their combinations on the bioavailability of Ni after their application into a Ni-polluted soil. The bioavailability of Ni after the application of immobilizing agents was assessed through an indicator plant (red clover) and chemical indicators of bioavailability like soil water extract (SWE), DTPA and Ca(NO 3 ) 2 extracts. Additionally, the effects of Ni bioavailability and immobilizing agents on the growth, physiological and biochemical attributes of red clover were also observed. Application of ZE significantly reduced Ni concentrations in all chemical extracts compared to rest of the treatments. Similarly, the combined application of BC and ZE (BC+ ZE) significantly reduced Ni concentrations, reactive oxygen species (ROS) whereas, significant enhancement in the growth, physiological and biochemical attributes along with an improvement in antioxidant defence machinery of red clover plant, compared to rest of the treatments, were observed. Furthermore, BC+ ZE treatment significantly reduced bioconcentration factor (BCF) and bioaccumulation factor (BAF) of Ni in red clover, compared to rest of the treatments. The Ni concentrations in red clover leaves individually reflected a good correlation with Ni concentrations in the extracts (SWE at R 2 =0.79, DTPA extract at R 2 =0.84 and Ca(NO 3 ) 2 extracts at R 2 =0.86). Our results indicate that combined application of ZE and BC can significantly reduce the Ni bioavailability in the soil while in parallel improve the antioxidant defence mechanism in plants. Copyright © 2017 Elsevier Inc. All rights reserved.
Modelling interactions in grass-clover mixtures
Nassiri Mahallati, M.
1998-01-01
The study described in this thesis focuses on a quantitative understanding of the complex interactions in binary mixtures of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) under cutting. The first part of the study describes the dynamics of growth, production
Sótér, A.; Kobayashi, T.; Barna, D.; Horváth, D.; Hori, M.
2014-01-01
The Atomic Spectroscopy and Collisions Using Slow Antiprotons (ASACUSA) experiment at the Antiproton Decelerator (AD) facility of CERN constructed segmented scintillators to detect and track the charged pions which emerge from antiproton annihilations in a future superconducting radiofrequency Paul trap for antiprotons. A system of 541 cast and extruded scintillator bars were arranged in 11 detector modules which provided a spatial resolution of 17 mm. Green wavelength-shifting fibers were embedded in the scintillators, and read out by silicon photomultipliers which had a sensitive area of 1 x 1 mm^2. The photoelectron yields of various scintillator configurations were measured using a negative pion beam of momentum p ~ 1 GeV/c. Various fibers and silicon photomultipliers, fiber end terminations, and couplings between the fibers and scintillators were compared. The detectors were also tested using the antiproton beam of the AD. Nonlinear effects due to the saturation of the silicon photomultiplier were seen a...
International Nuclear Information System (INIS)
Danchev, M.; Pavan, J.; Stone, N.J.; Stuchbery, A.E.; Baktash, C.; Beene, J.; Benczer-Koller, N.; Bingham, C.R.; Dupak, J.; Galindo-Uribarri, A.; Gross, C.J.; Kumbartzki, G.; Radford, D.C.; Stone, J.R.; Timlin, C.L.; Yu, C.-H.; Zamfir, N.V.
2005-01-01
We demonstrate that the recoil-in-vacuum (RIV) method can be used to determine the g-factor of the Coulumb excited first 2 + state of 132 Te. This was possible owing to advantages provided by CLARION (ORNL clover multi-detector array) and the segmented charged particle detector HyBall. Calibratory experiments were performed with 122,126,13 Te and a g-factor of 132 Te was deduced g = (+)0.35(5)
Arrays of Segmented, Tapered Light Guides for Use With Large, Planar Scintillation Detectors
Raylman, Raymond R.; Vaigneur, Keith; Stolin, Alexander V.; Jaliparthi, Gangadhar
2015-06-01
Metabolic imaging techniques can potentially improve detection and diagnosis of cancer in women with radiodense and/or fibrocystic breasts. Our group has previously developed a high-resolution positron emission tomography imaging and biopsy device (PEM-PET) to detect and guide the biopsy of suspicious breast lesions. Initial testing revealed that the imaging field-of-view (FOV) of the scanner was smaller than the physical size of the detector's active area, which could hinder sampling of breast areas close to the chest wall. The purpose of this work was to utilize segmented, tapered light guides for optically coupling the scintillator arrays to arrays of position-sensitive photomultipliers to increase both the active FOV and identification of individual scintillator elements. Testing of the new system revealed that the optics of these structures made it possible to discern detector elements from the complete active area of the detector face. In the previous system the top and bottom rows and left and right columns were not identifiable. Additionally, use of the new light guides increased the contrast of individual detector elements by up to 129%. Improved element identification led to a spatial resolution increase by approximately 12%. Due to attenuation of light in the light guides the detector energy resolution decreased from 18.5% to 19.1%. Overall, these improvements should increase the field-of-view and spatial resolution of the dedicated breast-PET system.
Energy Technology Data Exchange (ETDEWEB)
Han, L
1995-05-01
The aim of this thesis is the development of new types of germanium detectors: the composite detectors. Two types of prototypes are then conceived: the stacked planar detector (EDP) and the assembly of coaxial diodes (TREFLE). They are designed for the multidetector EUROGAM destined to the research of nuclear structure at high angular momentum. The four planar diodes of EDP detector were of 7 cm diameter and of 15 to 20 mm thick. The difference between the calculated and measured photopic efficiency is observed. The importance of surface channel induces a weak resistance of neutron damages. The sputtering method for the surface treatment reducing the germanium dead layer as well as a rule of selection concerning the impurity concentration and the thickness of crystal is helpful for the later production of germanium detector. The CLOVER detector consist of for mean size crystals in the same cryostat. The photopic efficiency is much larger than that of the greatest monocrystal detector. And the granulation of composite detector allowed the Doppler broadening correction of gamma ray observed in the nuclear reaction where the recoil velocity is very high. This new type of detector enable the linear polarization measurement of gamma ray. Twenty-four CLOVER detector are actually mounted in the EUROGAM array. The characteristics measured in source as well as in beam, reported in this thesis, meet exactly the charge account. (author). 47 refs., 61 figs., 18 tabs.
Transformation kinetics of corn and clover residues in mineral substrates of different composition
Pinskii, D. L.; Maltseva, A. N.; Zolotareva, B. N.; Dmitrieva, E. D.
2017-06-01
Mineralization kinetics of corn and clover residues in quartz sand, loam, sand + 15% bentonite, and sand + 30% kaolinite have been studied. A scheme has been proposed for the transformation of plant residues in mineral substrates. Kinetic parameters of mineralization have been calculated with the use of a first-order two-term exponential polynomial. It has been shown that the share of labile organic carbon pool in the clover biomass is higher (57-63%) than in the corn biomass (47-49%), which is related to the biochemical composition of plant residues. The mineralization constants of clover residues generally significantly exceed those of corn because of the stronger stabilization of the decomposition products of corn residues. The turnover time of the labile clover pool (4-9 days) in all substrates and that of the labile corn pool (8-10 days) in sands and substrates containing kaolinites and bentonite are typical for organic acids, amino acids, and simple sugars. In the loamy substrate, the turnover time of labile corn pool is about 46 days due to the stronger stabilization of components of the labile pool containing large amounts of organic acids. The turnover time of the stable clover pool (0.95 years) is significantly lower than that of the stable corn pool (1.60 years) and largely corresponds to the turnover time of plant biomass.
A New NPGS Special Collection: Norman L. Taylor University of Kentucky Clover Collection
Dr. Norman L. Taylor was a world renowned Professor and clover breeder in the Department of Plant and Soil Sciences at the University of Kentucky for 48 years. Following retirement in 2001, he continued working on clovers up until his death in 2010. Dr. Taylor’s entire career was devoted to enhancin...
Braem, André; Joram, Christian; Mathot, Serge; Séguinot, Jacques; Weilhammer, Peter; Ciocia, F; De Leo, R; Nappi, E; Vilardi, I; Argentieri, A; Corsi, F; Dragone, A; Pasqua, D
2007-01-01
We describe the design, fabrication and test results of a segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics. Both the photodetector and its VLSI readout electronics are custom designed and have been tailored to the requirements of a recently proposed novel geometrical concept of a Positron Emission Tomograph. Emphasis is laid on the PET specific features of the device. The detector has been fabricated in the photocathode facility at CERN.
International Nuclear Information System (INIS)
Brunot, S.; Corneloup, O.; Latrabe, V.; Montaudon, M.; Laurent, F.
2005-01-01
The aim of this study was to evaluate the inter-observer and intra-observer agreement of the diagnosis of sub-segmental acute pulmonary embolism (PE) in an inpatient population explored by 16 slice multi-detector spiral computed tomography (MDCT). Four hundred consecutive inpatients were referred for MDCT for the clinical suspicion of acute PE. One hundred and seventy seven (44.2%) had a known cardio-respiratory disease at the time of examination. Inter-observer and intra-observer agreements for the diagnosis of acute PE and of sub-segmental acute PE were assessed blind and independently by three experienced readers and by kappa statistics. Seventy-five patients were diagnosed as having acute PE findings (19.5%), and clots were located exclusively within sub-segmental arteries in nine patients (12%). When clots were limited to sub-segmental or more distal branches of the pulmonary arteries, kappa values were found to be moderate (0.56) to very good (0.85) for the diagnosis of sub-segmental acute PE, whereas for the diagnosis of acute PE in the whole population, kappa values ranged from 0.84 to 0.97. Intra-observer agreement was found to be perfect (kappa=1). MDCT is a reproducible technique for the diagnosis of sub-segmental acute PE as well as for acute PE. In this inpatient population, sub-segmental acute PE was not a rare event. (orig.)
N transfer in three species grass-clover mixtures with chicory, ribwort plantain or caraway
DEFF Research Database (Denmark)
Dhamala, Nawa Raj; Rasmussen, Jim; Carlsson, Georg
2017-01-01
Background and aimsThere is substantial evidence that legume-derived Nitrogen (N) is transferred to neighboring non-legumes in grassland mixtures. However, there is sparse information about how deep rooted non-legume forage herbs (forbs) influence N transfer in multi-species grasslands. Methodology......Red clover (Trifolium pretense L.) was grown together with perennial ryegrass (Lolium perenne L.) and one of three forb species: chicory (Cichorium intybus L.), ribwort plantain (Plantago lanceolata L.) or caraway (Carum carvi L.) in a field experiment. During the first year after the establishment, red...... clover leaves were labeled with 15N-urea to determine the N transfer from red clover to companion ryegrass and forbs. ResultsOn an annual basis, up to 15 % of red clover N was transferred to the companion ryegrass and forbs, but predominantly to the grass. The forb species did not differ in their ability...
DEFF Research Database (Denmark)
Cong, Wenfeng; Jing, Jingying; Søegaard, Karen
-containing grass-clover mixtures may potentially affect soil microbial community structure, biomass and associated ecosystem functions, but it is yet to be elucidated. We hypothesized that inclusion of plantain in the grass-clover mixture would enhance soil microbial biomas and functions through its high biomass...
International Nuclear Information System (INIS)
Casse, G.; Allport, P.P.; Bowcock, T.J.V.; Greenall, A.; Hanlon, M.; Jackson, J.N.
2002-01-01
Radiation damage of n-type bulk detectors introduces stable defects acting as effective p-type doping and leads to the change of the conductivity type of the silicon substrate (type inversion) after a fluence of a few times 10 13 protons cm -2 . The diode junction after inversion migrates from the original side to the back plane of the detector. The migration of the junction can be prevented using silicon detectors with p-type substrates. Furthermore, the use of n-side readout gives higher charge collection efficiency for segmented devices operated below the full depletion voltage. Large area (∼6.4x6.4 cm 2 ) capacitively coupled 80 μm pitch detectors using polysilicon bias resistors have been fabricated on p-type substrates (n-in-p diode structure). These detectors have been irradiated with 24 GeV/c protons to an integrated fluence of 3x10 14 cm -2 and kept for 7 days at 25 deg. C to reach the broad minimum of the annealing curve. Results are presented on the comparison of their charge collection properties with detectors using p-strip read-out after corresponding dose and annealing
Production of N2O in grass-clover pastures
International Nuclear Information System (INIS)
Carter, M.S.
2005-09-01
Agricultural soils are known to be a considerable source of the strong greenhouse gas nitrous oxide (N 2 O), and in soil N 2 O is mainly produced by nitrifying and denitrifying bacteria. In Denmark, grass-clover pastures are an important component of the cropping system in organic as well as conventional dairy farming, and on a European scale grass-clover mixtures represent a large part of the grazed grasslands. Biological dinitrogen (N 2 ) fixation in clover provides a major N input to these systems, but knowledge is sparse regarding the amount of fixed N 2 lost from the grasslands as N2O. Furthermore, urine patches deposited by grazing cattle are known to be hot-spots of N 2 O emission, but the mechanisms involved in the N 2 O production in urine-affected soil are very complex and not well understood. The aim of this Ph.D. project was to increase the knowledge of the biological and physical-chemical mechanisms, which control the production of N2O in grazed grass-clover pastures. Three experimental studies were conducted with the objectives of: 1: assessing the contribution of recently fixed N 2 as a source of N 2 O. 2: examining the link between N 2 O emission and carbon mineralization in urine patches. 3: investigating the effect of urine on the rates and N 2 O loss ratios of nitrification and denitrification, and evaluating the impact of the chemical conditions that arise in urine affected soil. The results revealed that only 3.2 ± 0.5 ppm of the recently fixed N 2 was emitted as N2O on a daily basis. Thus, recently fixed N released via easily degradable clover residues appears to be a minor source of N2O. Furthermore, increased N 2 O emission following urine application at rates up to 5.5 g N m -2 was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots. Finally, the increase of soil pH and ammonium following urine application led to raised nitrification rate, which appeared to be the most important factor
Accounting for segment correlations in segmented gamma-ray scans
International Nuclear Information System (INIS)
Sheppard, G.A.; Prettyman, T.H.; Piquette, E.C.
1994-01-01
In a typical segmented gamma-ray scanner (SGS), the detector's field of view is collimated so that a complete horizontal slice or segment of the desired thickness is visible. Ordinarily, the collimator is not deep enough to exclude gamma rays emitted from sample volumes above and below the segment aligned with the collimator. This can lead to assay biases, particularly for certain radioactive-material distributions. Another consequence of the collimator's low aspect ratio is that segment assays at the top and bottom of the sample are biased low because the detector's field of view is not filled. This effect is ordinarily countered by placing the sample on a low-Z pedestal and scanning one or more segment thicknesses below and above the sample. This takes extra time, however, We have investigated a number of techniques that both account for correlated segments and correct for end effects in SGS assays. Also, we have developed an algorithm that facilitates estimates of assay precision. Six calculation methods have been compared by evaluating the results of thousands of simulated, assays for three types of gamma-ray source distribution and ten masses. We will report on these computational studies and their experimental verification
Effect of fertilizer type on cadmium and fluorine concentrations in clover herbage
International Nuclear Information System (INIS)
McLaughlin, M.J.
2002-01-01
This study investigated whether changing phosphatic fertilizer type affects the accumulation of cadmium (Cd) and fluorine (F) in pasture herbage. North Carolina phosphate rock and partially acidulated fertilizers derived from this rock generally have higher Cd and F concentrations compared to single superphosphate currently manufactured in Australia. Clover herbage from sites of the National Reactive Phosphate Rock (RPR) trial was collected and analysed for concentrations of Cd (11 sites) and F (4 sites). A comparison was made between pastures fertilized with 4 rates of single superphosphate, North Carolina phosphate rock, and partially acidulated phosphate rock having Cd concentrations of 283, 481, and 420 mg Cd/kg P respectively, and 170, 271, and 274 g F/kg P respectively. One site used Hemrawein (Egypt) phosphate rock (HRP) having a Cd and F concentration of 78 mg Cd/kg P and 256 g F/kg P respectively. To help identify differences in herbage Cd concentrations between sites, unfertilised soils from each site were analyzed for total and extractable Cd contents. At one site Cd concentrations in bulk herbage (clover, grasses and weeds) were related to infestation of the pasture by capeweed (Arctotheca calendula L. Levyns). There were no significant differences between F in herbage from plots fertilized with single superphosphate, partially acidulated phosphate rock or North Carolina phosphate rock, or between sites. Concentrations of F in herbage were low, generally less than 10 mg F /kg. However, there were large differences in Cd concentrations in herbage between sites, while differences between fertilizer treatments were small in comparison. The site differences were only weakly related to total or extractable (0.01 mol/L CaCl 2 ) Cd concentrations in soil. Significant differences in Cd concentrations in clover due to fertilizer type were found at 5 sites. North Carolina phosphate rock treatments had significantly higher Cd concentrations in clover compared to
Effects of clover density on N2O emissions and plant-soil N transfers in a fertilised upland pasture
DEFF Research Database (Denmark)
Klumpp, Katja; Bloor, Juliette M. G.; Ambus, Per
2011-01-01
regression analysis revealed that water-filled pore space (WFPS) and clover dry mass were the main factors driving cumulative N2O emissions in the high clover treatment, whereas variation in cumulated N2O emissions in the low clover treatment was best explained by WFPS and grass mass. We hypothesize...
International Nuclear Information System (INIS)
Doncel, M.; Recchia, F.; Quintana, B.; Gadea, A.; Farnea, E.
2010-01-01
The development of highly segmented germanium detectors as well as the algorithms to identify the position of the interaction within the crystal opens the possibility to locate the γ-ray source using Compton imaging algorithms. While the Compton-suppression shield, coupled to the germanium detector in conventional arrays, works also as an active filter against the γ rays originated outside the target, the new generation of position sensitive γ-ray detector arrays has to fully rely on tracking capabilities for this purpose. In specific experimental conditions, as the ones foreseen at radioactive beam facilities, the ability to discriminate background radiation improves the sensitivity of the gamma spectrometer. In this work we present the results of a measurement performed at the Laboratori Nazionali di Legnaro (LNL) aiming the evaluation of the AGATA detector capabilities to discriminate the origin of the γ rays on an event-by-event basis. It will be shown that, exploiting the Compton scattering formula, it is possible to track back γ rays coming from different positions, assigning them to specific emitting locations. These imaging capabilities are quantified for a single crystal AGATA detector.
Energy Technology Data Exchange (ETDEWEB)
Marchal, J [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)], E-mail: julien.marchal@diamond.ac.uk
2010-01-15
A detector cascaded model is proposed to describe charge-sharing effect in single-photon counting segmented silicon detectors. Linear system theory is applied to this cascaded model in order to derive detector performance parameters such as large-area gain, presampling Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE) as a function of energy detection threshold. This theory is used to model one-dimensional detectors (i.e. strip detectors) where X-ray-generated charge can be shared between two sampling elements, but the concepts developed in this article can be generalized to two-dimensional arrays of detecting elements (i.e. pixels detectors). The zero-frequency DQE derived from this model is consistent with expressions reported in the literature using a different method. The ability of this model to simulate the effect of charge sharing on image quality in the spatial frequency domain is demonstrated by applying it to a hypothetical one-dimensional single-photon counting detector illuminated with a typical mammography spectrum.
2010-01-01
... foreign alfalfa or red clover seed is not adapted for general agricultural use in the United States. 202... Proceedings under section 305(b) to determine whether foreign alfalfa or red clover seed is not adapted for... for the purpose of determining whether seed of alfalfa or red clover from any foreign country or...
Association of phytoplasmas and viruses with malformed clovers
Czech Academy of Sciences Publication Activity Database
Fránová, Jana; Paltrinieri, S.; Botti, S.; Šimková, Marie; Bertaccini, A.
2004-01-01
Roč. 49, č. 5 (2004), s. 617-624 ISSN 0015-5632 R&D Projects: GA AV ČR IBS5051014 Institutional research plan: CEZ:AV0Z5051902 Keywords : mycoplasma-like organismus * viruses * clovers * classification Subject RIV: EE - Microbiology, Virology Impact factor: 1.034, year: 2004
Spectral response of multi-element silicon detectors
Energy Technology Data Exchange (ETDEWEB)
Ludewigt, B.A.; Rossington, C.S.; Chapman, K. [Univ. of California, Berkeley, CA (United States)
1997-04-01
Multi-element silicon strip detectors, in conjunction with integrated circuit pulse-processing electronics, offer an attractive alternative to conventional lithium-drifted silicon Si(Li) and high purity germanium detectors (HPGe) for high count rate, low noise synchrotron x-ray fluorescence applications. One of the major differences between the segmented Si detectors and the commercially available single-element Si(Li) or HPGe detectors is that hundreds of elements can be fabricated on a single Si substrate using standard silicon processing technologies. The segmentation of the detector substrate into many small elements results in very low noise performance at or near, room temperature, and the count rate of the detector is increased many-fold due to the multiplication in the total number of detectors. Traditionally, a single channel of detector with electronics can handle {approximately}100 kHz count rates while maintaining good energy resolution; the segmented detectors can operate at greater than MHz count rates merely due to the multiplication in the number of channels. One of the most critical aspects in the development of the segmented detectors is characterizing the charge sharing and charge loss that occur between the individual detector strips, and determining how these affect the spectral response of the detectors.
Nitrogen fertilization of grass/clover swards under cutting or grazing by dairy cows
DEFF Research Database (Denmark)
Søegaard, Karen
2009-01-01
farms over a period of three years. Nitrogen was applied at four rates (0, 75, 150, and 225 kg N year-1) with cutting or grazing regime in Year 1 and Year 2, after establishment. A spring-only application of 150 kg N was compared with four applications during the season, which was the fertilization...... affected. The results indicate different possibilities for strategic fertilization both at farm and field level, and in swards with a high clover content it demonstrates how the clover content can be used as a buffer both for maximizing the N-response and for manipulating the production profile.......Intensively managed perennial ryegrass/white clover (Lolium perenne L. and Trifolium repens L.) swards receive relatively high levels of fertilizer N, and high N surpluses can subsequently be found. The N-fertilization effects on growth, yield, and herbage quality were therefore examined on three...
Czech Academy of Sciences Publication Activity Database
Neděla, Vilém; Konvalina, Ivo; Oral, Martin; Hudec, Jiří
2015-01-01
Roč. 21, S4 (2015), s. 264-269 ISSN 1431-9276 R&D Projects: GA ČR(CZ) GA14-22777S Institutional support: RVO:68081731 Keywords : electron-gas interactions * Monte Carlo simulation * signal amplification * segmented ionization detector Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.730, year: 2015
PERSISTENCE ASSESSMENT OF RED CLOVER (Trifolium pratense L. IN TÂRGOVISTE PLAIN
Directory of Open Access Journals (Sweden)
D. DUNEA
2008-05-01
Full Text Available Since the most important deficiency of forage stands is the inability to maintain adequate legume participation in mixture, it is the purpose of this paper to examine persistence in red clover in Târgoviste Plain eco-climatic conditions, together with the factors that affect it. Six red clover cultivars (Napoca-Tetra, Dacia Tetra, Vesna – tetraploids; Flora, Roxana, Start – diploids and one white clover diploid cultivar (Karina were used in pure culture and in mixture (50:50 with hybrid ryegrass (Zefir – tetraploid in a randomized block design with three replicates. Ground cover assessment in early spring was a suggestive indicator of the stand persistence to define the stability and sustainability boundaries of a reliable intensive system. In the beginning of the third year of cropping, ground cover was 54.33% for tetraploid cultivars (CV = 43.25%, and 67% for diploid cultivars (CV = 6.83% in pure stands. Same ground cover average of 27% was established both for tetraploid cultivars (CV = 36.47%, and for diploid cultivars (CV = 16.97% in mixtures with hybrid ryegrass.
Effects of Titanium Dioxide Nanoparticles on Red Clover and Its Rhizobial Symbiont.
Moll, Janine; Okupnik, Annette; Gogos, Alexander; Knauer, Katja; Bucheli, Thomas D; van der Heijden, Marcel G A; Widmer, Franco
2016-01-01
Titanium dioxide nanoparticles (TiO2 NPs) are in consideration to be used in plant protection products. Before these products can be placed on the market, ecotoxicological tests have to be performed. In this study, the nitrogen fixing bacterium Rhizobium trifolii and red clover were exposed to two TiO2 NPs, i.e., P25, E171 and a non-nanomaterial TiO2. Growth of both organisms individually and their symbiotic root nodulation were investigated in liquid and hydroponic systems. While 23 and 18 mg l-1 of E171 and non-nanomaterial TiO2 decreased the growth rate of R. trifolii by 43 and 23% respectively, P25 did not cause effects. Shoot length of red clover decreased between 41 and 62% for all tested TiO2 NPs. In 21% of the TiO2 NP treated plants, no nodules were found. At high concentrations certain TiO2 NPs impaired R. trifolii as well as red clover growth and their symbiosis in the hydroponic systems.
Effects of Titanium Dioxide Nanoparticles on Red Clover and Its Rhizobial Symbiont.
Directory of Open Access Journals (Sweden)
Janine Moll
Full Text Available Titanium dioxide nanoparticles (TiO2 NPs are in consideration to be used in plant protection products. Before these products can be placed on the market, ecotoxicological tests have to be performed. In this study, the nitrogen fixing bacterium Rhizobium trifolii and red clover were exposed to two TiO2 NPs, i.e., P25, E171 and a non-nanomaterial TiO2. Growth of both organisms individually and their symbiotic root nodulation were investigated in liquid and hydroponic systems. While 23 and 18 mg l-1 of E171 and non-nanomaterial TiO2 decreased the growth rate of R. trifolii by 43 and 23% respectively, P25 did not cause effects. Shoot length of red clover decreased between 41 and 62% for all tested TiO2 NPs. In 21% of the TiO2 NP treated plants, no nodules were found. At high concentrations certain TiO2 NPs impaired R. trifolii as well as red clover growth and their symbiosis in the hydroponic systems.
Performance of the clover detector considering the effects of pair production
International Nuclear Information System (INIS)
Kshetri, Ritesh
2015-01-01
Gamma rays having sufficient energy to produce positron-electron pairs in a detector generate three peaks in the energy spectrum, corresponding to the full gamma-ray energy, and this gamma-ray energy minus 511 and 1022 keV because of the single and double escape of the 511 keV annihilation quanta. The escape peaks are frequently used to extend the precision of energy calibration, simply by providing additional spectral peaks at well-known energies. At energies around 6 MeV, the pair production process dominates over other gamma interaction processes in germanium. It has been observed that the intensity of the single and double escape peaks (SEP and DEP) for gamma-rays around these energies increases rapidly. This results in a difficulty to correctly identify new gamma-rays, which is crucial for precision gamma-ray spectroscopy that involves mostly the use of tapered cylindrical germanium detectors
Genetic variation of white clover ( Trifolium repens L.) collections ...
African Journals Online (AJOL)
amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) to investigate the genetic relationships among white clover germplasms of China, and four commercial cultivars were included for a comparison. The results revealed that the populations showed diverse morphological traits, RAPD and SSR patterns.
Production of N{sub 2}O in grass-clover pastures
Energy Technology Data Exchange (ETDEWEB)
Carter, M.S.
2005-09-01
Agricultural soils are known to be a considerable source of the strong greenhouse gas nitrous oxide (N{sub 2}O), and in soil N{sub 2}O is mainly produced by nitrifying and denitrifying bacteria. In Denmark, grass-clover pastures are an important component of the cropping system in organic as well as conventional dairy farming, and on a European scale grass-clover mixtures represent a large part of the grazed grasslands. Biological dinitrogen (N{sub 2}) fixation in clover provides a major N input to these systems, but knowledge is sparse regarding the amount of fixed N{sub 2} lost from the grasslands as N2O. Furthermore, urine patches deposited by grazing cattle are known to be hot-spots of N{sub 2}O emission, but the mechanisms involved in the N{sub 2}O production in urine-affected soil are very complex and not well understood. The aim of this Ph.D. project was to increase the knowledge of the biological and physical-chemical mechanisms, which control the production of N2O in grazed grass-clover pastures. Three experimental studies were conducted with the objectives of: 1: assessing the contribution of recently fixed N{sub 2} as a source of N{sub 2}O. 2: examining the link between N{sub 2}O emission and carbon mineralization in urine patches. 3: investigating the effect of urine on the rates and N{sub 2}O loss ratios of nitrification and denitrification, and evaluating the impact of the chemical conditions that arise in urine affected soil. The results revealed that only 3.2 {+-} 0.5 ppm of the recently fixed N{sub 2} was emitted as N2O on a daily basis. Thus, recently fixed N released via easily degradable clover residues appears to be a minor source of N2O. Furthermore, increased N{sub 2}O emission following urine application at rates up to 5.5 g N m{sup -2} was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots. Finally, the increase of soil pH and ammonium following urine application led to raised
Energy Technology Data Exchange (ETDEWEB)
Ritchey, K.D.; Belesky, D.P.; Halvorson, J.J. [USDA ARS, Beaver, WV (US). Appalachian Farming Systems Research Center
2004-12-01
Calcium-rich soil amendments can improve plant growth by supplying Ca and reducing detrimental effects of soil acidity, but solubility and neutralizing capacity of Ca sources vary. Our objectives were to evaluate effects of calcitic dolomite and several coal combustion by-products on soil properties at various depths 6 yr after surface application and their influence on grass-clover herbage accumulation. Calcium and Mg soil amendments were surface-applied to an acidic grassland in 1993, and orchardgrass (Dactylis glomerata L.) and tall fescue (Lolium arundinaceum (Schreb.) Darbyshire) were oversown in 1994. In 1998, amendment treatment plots were split to accommodate sod seeding with red clover (Trifolium pratense L.) or white clover (T. repens L.) as well as a nonseeded control. No N fertilizer was applied after sod seeding. Six years after amendment application, reductions in soil Al and Mn and increases in Ca and pH from 4654 kg ha{sup -1} calcitic dolomite, 15 000 kg ha{sup -1} fluidized bed combustion residue, or 526 kg ha{sup -1} MgO amendment were greatest in the surface 2.5 cm while rates of gypsum as high as 32 000 kg ha{sup -1} left little residual effect except for decreases in Mg. Percentage clover in the sward tripled as pH increased from 4.3 to 5.0 while herbage mass increased 75% as clover percentage increased. Herbage mass was generally more closely correlated with properties of soil samples collected from the surface 2.5 cm than from deeper samples.
DEFF Research Database (Denmark)
Wermuth, Kirsten Haugaard; Dupont, Yoko L.
2010-01-01
Red clover is a key floral ressource for bumblebees (Bombus spp.).We here investigate variation within and among red clover fields in species richness and abundance of Bombus spp. in addition to Apis mellifera. Bumblebee individuals were grouped into the following functional groups, based on castes...
DEFF Research Database (Denmark)
Brozyna, Michal Adam; Petersen, Søren O; Chirinda, Ngoni
2013-01-01
Nitrogen (N) supply in stockless organic farming may be improved through use of grass-clover for anaerobic digestion, producing biogas and digested manure for use as fertilizer in the crop rotation. We studied the effects of grass-clover management on N cycling, nitrous oxide (N2O) emissions...... in the rotation (spring barley, potato and winter wheat); actual digestion of grass-clover cuttings was not possible, instead digested pig manure was used as substitute for digested grass-clover. Nitrous oxide fluxes were monitored between April 2008 and May 2009. In general, application of digested manure had...
DEFF Research Database (Denmark)
Andersen, C; Nielsen, T S; Purup, S
2009-01-01
A grazing experiment was carried out to study the concentration of phyto-oestrogens in herbage for cattle and in milk during two periods (May and June). Forty-eight Danish Holstein cows were divided into four groups with four treatment diets; white clover, red clover, lucerne and chicory-rich pas...
Investigation of reduction in background counts of clover detector
International Nuclear Information System (INIS)
Kshetri, Ritesh
2015-01-01
The peak-to-total ratio can be improved by increasing the full energy peak (FEP) counts and/or by decreasing the background counts. It is notable that FEP counts will be effected by mode of operation, while background counts will be effected by both modes of operation and suppression cases. It would be interesting to know if the reduction in background is caused more by active suppression or by add back process. We introduce a simple formalism to investigate the reduction of background counts for different cases-single crystal or add back mode with active or passive suppression. A more sophisticated formalism for modeling a general composite detector had been presented in a series of six recent papers by the author
Gamma-Ray Spectroscopy at TRIUMF-ISAC: the New Frontier of Radioactive Ion Beam Research
Ball, G. C.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Becker, J. A.; Bricault, P.; Brown, N.; Chan, S.; Churchman, R.; Colosimo, S.; Coombes, H.; Cross, D.; Demand, G.; Drake, T. E.; Dombsky, M.; Ettenauer, S.; Finlay, P.; Furse, D.; Garnsworthy, A.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hyland, B.; Hackman, G.; Kanungo, R.; Kulp, W. D.; Lassen, J.; Leach, K. G.; Leslie, J. R.; Mattoon, C.; Melconian, D.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Rand, E.; Sarazin, F.; Svensson, C. E.; Sumithrarachchi, S.; Schumaker, M. A.; Triambak, S.; Waddington, J. C.; Walker, P. M.; Williams, S. J.; Wood, J. L.; Wong, J.; Zganjar, E. F.
2009-03-01
High-resolution gamma-ray spectroscopy is essential to fully exploit the unique scientific opportunities at the next generation radioactive ion beam facilities such as the TRIUMF Isotope Separator and Accelerator (ISAC). At ISAC the 8π spectrometer and its associated auxiliary detectors is optimize for β-decay studies while TIGRESS an array of segmented clover HPGe detectors has been designed for studies with accelerated beams. This paper gives a brief overview of these facilities and also presents recent examples of the diverse experimental program carried out at the 8π spectrometer.
Improving Resilience of Northern Field Crop Systems Using Inter-Seeded Red Clover: A Review
Directory of Open Access Journals (Sweden)
William Deen
2013-02-01
Full Text Available In light of the environmental challenges ahead, resilience of the most abundant field crop production systems must be improved to guarantee yield stability with more efficient use of nitrogen inputs, soil and water resources. Along with genetic and agronomic innovations, diversification of northern agro-ecosystems using inter-seeded legumes provides further opportunities to improve land management practices that sustain crop yields and their resilience to biotic and abiotic stresses. Benefits of legume cover crops have been known for decades and red clover (Trifolium pratense is one of the most common and beneficial when frost-seeded under winter wheat in advance of maize in a rotation. However, its use has been declining mostly due to the use of synthetic fertilizers and herbicides, concerns over competition with the main crop and the inability to fully capture red clover benefits due to difficulties in the persistence of uniform stands. In this manuscript, we first review the environmental, agronomic, rotational and economical benefits associated with inter-seeded red clover. Red clover adaptation to a wide array of common wheat-based rotations, its potential to mitigate the effects of land degradation in a changing climate and its integration into sustainable food production systems are discussed. We then identify areas of research with significant potential to impact cropping system profitability and sustainability.
International Nuclear Information System (INIS)
Wang Haipeng; Fan Xin; Yun Mingkai; Liu Shuangquan; Cao Xuexiang; Chai Pei; Shan Baoci
2015-01-01
In a scintillation detector, scintillation crystals are typically made into a 2-dimensional modular array. The location of incident gamma-ray needs be calibrated due to spatial response nonlinearity. Generally, position histograms-the characteristic flood response of scintillation detectors-are used for position calibration. In this paper, a position calibration method based on a crystal position lookup table which maps the inaccurate location calculated by Anger logic to the exact hitting crystal position has been proposed. Firstly, the position histogram is preprocessed, such as noise reduction and image enhancement. Then the processed position histogram is segmented into disconnected regions, and crystal marking points are labeled by finding the centroids of regions. Finally, crystal boundaries are determined and the crystal position lookup table is generated. The scheme is evaluated by the whole-body positron emission tomography (PET) scanner and breast dedicated single photon emission computed tomography scanner developed by the Institute of High Energy Physics, Chinese Academy of Sciences. The results demonstrate that the algorithm is accurate, efficient, robust and applicable to any configurations of scintillation detector. (authors)
Preliminary research on amino acid composition and nutritional value of clover proteins
Directory of Open Access Journals (Sweden)
L. Kłyszejko-Stefanowicz
2015-06-01
Full Text Available The amino acid composition and nutritional value of 5 clover varieties including 3 Polish ones ('Gloria', 'Hruszowska', 'Skrzeszowicka' and 2 of foreign origin ('Rotra' and 'Violetta' were investigated. No significant differences in the total protein content (19.2–20.0% of dry matter as well as in qualitative amino acid composition were found among the clover varieties under examination. EAA index (Essential amino acid index calculated according to Oser for 'Gloria' and 'Hruszowska' showed the highest nutritional value was – 40. The lowest value of EAA index was found for 'Violetta' cvar. – 32, intermediate values however for Rotra and Skrzeszowicka was 37 and 36.
Olsen, K M; Sutherland, B L; Small, L L
2007-10-01
White clover (Trifolium repens) is naturally polymorphic for cyanogenesis (hydrogen cyanide release following tissue damage). The ecological factors favouring cyanogenic and acyanogenic plants have been examined in numerous studies over the last half century, making this one of the best-documented examples of an adaptive polymorphism in plants. White clover cyanogenesis is controlled by two, independently segregating Mendelian genes: Ac/ac controls the presence/absence of cyanogenic glucosides; and Li/li controls the presence/absence of their hydrolysing enzyme, linamarase. In this study, we examine the molecular evolution and population genetics of Li as it relates to the cyanogenesis polymorphism. We report here that Li exists as a single-copy gene in plants possessing linamarase activity, and that the absence of enzyme activity in li/li plants is correlated with the absence of much or all of the gene from the white clover genome. Consistent with this finding, we confirm by reverse transcription-polymerase chain reaction that Li gene expression is absent in plants lacking enzyme activity. In a molecular population genetic analysis of Li and three unlinked genes using a worldwide sample of clover plants, we find an absence of nucleotide variation and statistically significant deviations from neutrality at Li; these findings are consistent with recent positive directional selection at this cyanogenesis locus.
DEFF Research Database (Denmark)
Stødkilde, Lene; Damborg, Vinni K; Jørgensen, Henry
2018-01-01
BACKGROUND: The aim was to evaluate white clover as an alternative protein source for monogastrics. White clover plant and leaves were processed using a screw-press resulting in a solid pulp and a juice from which protein was acid-precipitated. The chemical composition of all fractions...... was determined and digestibility of dry matter (DM) and protein was assessed in an experiment with growing rats. RESULTS: Protein concentrates were produced with crude protein (CP) content of 451 g/kg DM and 530 g/kg DM for white clover plant and leaves, respectively and a pulp with CP content of 313 and 374 g...
Electrical Signal Path Study and Component Assay for the MAJORANA N-Type Segmented Contact Detector
International Nuclear Information System (INIS)
Amman, Mark; Bergevin, Marc; Chan, Yuen-Dat; Detwiler, Jason A.; Fujikawa, Brian; Lesko, Kevin T.; Luke, Paul N.; Prior, Gersende; Poon, Alan W.; Smith, Alan R.; Vetter, Kai; Yaver, Harold; Zimmermann, Sergio
2009-01-01
The purpose of the present electrical signal path study is to explore the various issues related to the deployment of highly-segmented low-background Ge detectors for the MAJORANA double-beta decay experiment. A significant challenge is to simultaneously satisfy competing requirements for the mechanical design, electrical readout performance, and radiopurity specifications from the MAJORANA project. Common to all rare search experiments, there is a very stringent limit on the acceptable radioactivity level of all the electronics components involved. Some of the findings are summarized in this report.
Electrical Signal Path Study and Component Assay for the MAJORANA N-Type Segmented Contact Detector
Energy Technology Data Exchange (ETDEWEB)
Amman, Mark; Bergevin, Marc; Chan, Yuen-Dat; Detwiler, Jason A.; Fujikawa, Brian .; Lesko, Kevin T.; Luke, Paul N.; Prior, Gersende; Poon, Alan W.; Smith, Alan R.; Vetter, Kai; Yaver, Harold; Zimmermann, Sergio
2009-02-24
The purpose of the present electrical signal path study is to explore the various issues related to the deployment of highly-segmented low-background Ge detectors for the MAJORANA double-beta decay experiment. A significant challenge is to simultaneously satisfy competing requirements for the mechanical design, electrical readout performance, and radiopurity specifications from the MAJORANA project. Common to all rare search experiments, there is a very stringent limit on the acceptable radioactivity level of all the electronics components involved. Some of the findings are summarized in this report.
A Compton suppressed detector multiplicity trigger based digital DAQ for gamma-ray spectroscopy
Das, S.; Samanta, S.; Banik, R.; Bhattacharjee, R.; Basu, K.; Raut, R.; Ghugre, S. S.; Sinha, A. K.; Bhattacharya, S.; Imran, S.; Mukherjee, G.; Bhattacharyya, S.; Goswami, A.; Palit, R.; Tan, H.
2018-06-01
The development of a digitizer based pulse processing and data acquisition system for γ-ray spectroscopy with large detector arrays is presented. The system is based on 250 MHz 12-bit digitizers, and is triggered by a user chosen multiplicity of Compton suppressed detectors. The logic for trigger generation is similar to the one practised for analog (NIM/CAMAC) pulse processing electronics, while retaining the fast processing merits of the digitizer system. Codes for reduction of data acquired from the system have also been developed. The system has been tested with offline studies using radioactive sources as well as in the in-beam experiments with an array of Compton suppressed Clover detectors. The results obtained therefrom validate its use in spectroscopic efforts for nuclear structure investigations.
Genetic variation of white clover (Trifolium repens L.) collections ...
African Journals Online (AJOL)
STORAGESEVER
2010-05-24
May 24, 2010 ... incompatibility mechanism of disomic inheritance (Thomas,. 1987). In essence ..... Badr A, Sayed-Ahmed H, El-Shanshouri A, Watson LE (2002). Ancestors of white ... Caradus JR, Woodfield DR (1997). World checklist of ... within a natural population of white clover (Trifolium repense L). J. Ecol. 73: 615-624 ...
Growth of bermudagrass with white clover or nitrogen fertilizer
White clover (Trifolium repens) var ‘Durana’ was oversown into established bermudagrass (Cynodon dactylon) in 2009. Soil analysis indicated potassium (K) was low and potash at 112 and 336 kg/ha was added as main plots. Nitrogen as ammonium nitrate or an ammonium sulfate/urea blend was added as 0, 34...
Semiconductor detectors with proximity signal readout
International Nuclear Information System (INIS)
Asztalos, Stephen J.
2012-01-01
Semiconductor-based radiation detectors are routinely used for the detection, imaging, and spectroscopy of x-rays, gamma rays, and charged particles for applications in the areas of nuclear and medical physics, astrophysics, environmental remediation, nuclear nonproliferation, and homeland security. Detectors used for imaging and particle tracking are more complex in that they typically must also measure the location of the radiation interaction in addition to the deposited energy. In such detectors, the position measurement is often achieved by dividing or segmenting the electrodes into many strips or pixels and then reading out the signals from all of the electrode segments. Fine electrode segmentation is problematic for many of the standard semiconductor detector technologies. Clearly there is a need for a semiconductor-based radiation detector technology that can achieve fine position resolution while maintaining the excellent energy resolution intrinsic to semiconductor detectors, can be fabricated through simple processes, does not require complex electrical interconnections to the detector, and can reduce the number of required channels of readout electronics. Proximity electrode signal readout (PESR), in which the electrodes are not in physical contact with the detector surface, satisfies this need
Nitrogen transfer via VA mycorrhiza hyphae link between roots of red clover
International Nuclear Information System (INIS)
Zhang Junling; Li Xiaolin; Yang Zhifu
1997-01-01
Five compartments with a air gap was designed to examine underground N transfer via VAM hyphae link between roots of red clover. 15 N was injected into the root compartment for donor plant 4 weeks after planting. Plants were harvested 6 weeks afterwards. The experiment had four treatments: two N levels (receiver root compartment); mycorrhiza and non-mycorrhiza treatment (B compartment), and each with four replicates. It was demonstrated that there was no significant difference in 15 N abundance in receiver red clover regardless of the inoculation of mycorrhiza fungi and nitrogen fertilization. Both shoot and root dry weight of receiver plants were not affected too, however, plant P and N nutrient status got better under this condition
Energy Technology Data Exchange (ETDEWEB)
Starosta, K., E-mail: starosta@sfu.c [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Crawford, H.; Mantica, P. [National Superconducting Cyclotron Laboratory and Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W.K. [XIA LLC, Hayward, CA 94544 (United States)
2009-11-11
A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a gamma ray in a SeGA detector from implementation of gamma-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.
International Nuclear Information System (INIS)
Starosta, K.; Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T.; Crawford, H.; Mantica, P.; Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W.K.
2009-01-01
A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a γ ray in a SeGA detector from implementation of γ-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.
Starosta, K.; Vaman, C.; Miller, D.; Voss, P.; Bazin, D.; Glasmacher, T.; Crawford, H.; Mantica, P.; Tan, H.; Hennig, W.; Walby, M.; Fallu-Labruyere, A.; Harris, J.; Breus, D.; Grudberg, P.; Warburton, W. K.
2009-11-01
A 624-channel Digital Data Acquisition System capable of instrumenting the Segmented Germanium Array at National Superconducting Cyclotron Laboratory has been implemented using Pixie-16 Digital Gamma Finder modules by XIA LLC. The system opens an opportunity for determination of the first interaction position of a γ ray in a SeGA detector from implementation of γ-ray tracking. This will translate into a significantly improved determination of angle of emission, and in consequence much better Doppler corrections for experiments with fast beams. For stopped-beam experiments the system provides means for zero dead time measurements of rare decays, which occur on time scales of microseconds.
Cleaning the Soil from Zinc Using Red Clovers “Arimaičiai”
Directory of Open Access Journals (Sweden)
Audronė Mikalajūnė
2011-02-01
Full Text Available Zinc as a nutrition element is required to plants in small quantities to maintain normal functions of metabolism mechanisms. Our work analyses the efficiency of red clovers “Arimaičiai” for cleaning zinc from the soil contaminated with zinc under laboratory conditions. Seeds were sown in three differently polluted soils: clean soil, once contaminated with zinc and periodically contaminated with zinc soil. Zinc concentration in one time contaminated soil was 45 mg/kg. After 6 months of phytoremediation, the remained zinc concentration in the soil was 3 times lower comparing with the initial concentration. It was also determined that under such conditions, the uptake of red clovers made approximately 65% of zinc. Permanent soil contamination with zinc increased concentration before phytoremediation up to 80 mg/kg. After 6 months of phytoremediation, zinc concentration was determined to be 1.9 times lower. Otherwise, the soil was permanently contaminated with larger zinc quantities and after application of which reached 300 mg/kg. In this case, following half a year of phytoremediation, zinc concentration in the soil was 1.7 times lower comparing with the initial concentration after contamination. It was determined that the uptake of red clovers made approximately 17% of zinc.Article in Lithuanian
Kinetics and optimization of red clover pulp drying
Directory of Open Access Journals (Sweden)
A. A. Shevtsov
2013-01-01
Full Text Available The kinetics of the drying process conducted with bagasse red clover on an experimental dry¬er superheated steam at atmospheric pressure in the active hydrodynamic regimes were study¬ing. The rational intervals of parameter changes were obtained. The problem of optimization, which allowed allocating the optimum range of variation of the input factors according to three criteria through compromise was solved.
Salt tolerance in red clover (Trifolium pratense L.) seedlings
African Journals Online (AJOL)
Jane
2011-08-15
Aug 15, 2011 ... This study was conducted to investigate the effect of salt stress on germination of 28 red clover. (Trifolium pratense ... tolerance with the aim of improving crop plants (Zhu,. 2001) or soil .... The interaction of salinity and population in terms of PI ... in shoot growth is probably due to hormonal signals generated ...
Estimating impact on clover-grass yield caused by traffic intensities
DEFF Research Database (Denmark)
Jørgensen, R N; Green, Ole; Kristensen, Kristian
2009-01-01
Steer and a 15 m3 Kimadan slurry tanker on two axels, was used to perform the simulated traffic treatment on the parcels. The different traffic intensities are combinations of different tire pressure (1,0 and 2,5 bar), tire load (3000 and 6000 kg), time of year and number of passes (variating from 0 to 8...... components must be determined. The objective of this paper was to measure yield affects on clover-grass as a consequence of different traffic intensities. The experiments were carried out in the context of a full scale field trial. A 14 hectare full scale grass-clover field trial with 24 different traffic......). The harvesting procedure was preformed with a Haldrup plot harvester modified with RTK-GPS. This paper shows the initial results from measuring the yield affects References M.A. Hamza, M.A.; Anderson, W.K 2005. Soil compaction in cropping systems: A review of the nature, causes and possible solutionsRaper , R...
Data acquisition system for segmented reactor antineutrino detector
Czech Academy of Sciences Publication Activity Database
Hons, Zdeněk; Vlášek, J.
2017-01-01
Roč. 12, č. 1 (2017), č. článku P01022. ISSN 1748-0221 R&D Projects: GA MŠk LG14004 Institutional support: RVO:61389005 Keywords : Data acquisition concepts * Detector control systems (detector and experiment monitoring and slow-control system, architecture , hardware, algorithms, databases) * Neutrino detectors Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.220, year: 2016
Kshetri, Ritesh
2012-01-01
In two recent papers (R. Kshetri, JINST 2012 7 P04008; ibid., P07006), a probabilistic formalism was introduced to predict the response of encapsulated type composite germanium detectors like the SPI (spectrometer for INTEGRAL satellite). Predictions for the peak-to-total and peak-to-background ratios are given at 1.3 MeV for the addback mode of operation. The application of the formalism to clover germanium detector is discussed in two separate papers (R. Kshetri, JINST 2012 7 P07008; ibid.,...
Ball, C
2010-07-01
The Industrial Revolution saw the creation of many new jobs, but probably none more curious than that of zookeeper. The London Zoological Gardens, established for members in 1828, was opened to the general public in 1847. In 1852 the "Head Keeper in the Serpent Room", Edward Horatio Girling, spent a night farewelling a friend departing for Australia. He arrived at work in an inebriated state and was bitten on the face by a cobra that he was handling in a less than sensible manner. He was taken by cab to University College Hospital where he was resuscitated by a number of doctors, including Joseph Clover then the resident medical officer to the hospital and later to become the leading anaesthetist in London. Clover recorded this event in his diary along with the resuscitation method used. The patient eventually died but his treatment created a flurry of correspondence in the medical and lay press. Interestingly, the attempted resuscitation was with bellows, which had been abandoned by the Royal Humane Society twenty years earlier Clover records other cases of resuscitation with bellows at University College Hospital during his time as a resident medical officer there (1848 to 1853). There is a casebook belonging to Joseph Clover in the Geoffrey Kaye Museum, in Melbourne. This story is one of the many interesting stories uncovered during a study of this book and Clover's other personal papers.
Moorby, J M; Ellis, N M; Davies, D R
2016-10-01
Twenty-four multiparous Holstein-Friesian dairy cows were used in a replicated 3×3 Latin square changeover design experiment to test the effects of changing from corn (Zea mays) silage to red clover (Trifolium pratense) silage in graded proportions on feed intakes, milk production, and whole-body N and P partitioning. Three dietary treatments with ad libitum access to 1 of 3 forage mixtures plus a standard allowance of 4kg/d dairy concentrates were offered. The 3 treatment forage mixtures were, on a dry matter (DM) basis: (1) R10: 90% corn silage and 10% red clover silage, (2) R50: 50% corn silage and 50% red clover silage, and (3) R90: 10% corn silage and 90% red clover silage. In each of 3 experimental periods, there were 21d for adaptation to diets, and 7d for measurements. Diet crude protein intakes increased, and starch intakes decreased, as the silage mixture changed from 90% corn to 90% red clover, although the highest forage DM intakes and milk yields were achieved on diet R50. Although milk fat yields were unaffected by diet, milk protein yields were highest with the R 0250 diet. Whole-body partitioning of N was measured in a subset of cows (n=9), and both the daily amount and proportion of N consumed that was excreted in feces and urine increased as the proportion of red clover silage in the diet increased. However, the apparent efficiency of utilization of feed N for milk protein production decreased from 0.33g/g for diet R10 to 0.25g/g for diet R90. The urinary excretion of purine derivatives (sum of allantoin and uric acid) tended to increase, suggesting greater flow of microbial protein from the rumen, as the proportion of red clover silage in the diet increased, and urinary creatinine excretion was affected by diet. Fecal shedding of E. coli was not affected by dietary treatment. In conclusion, even though microbial protein flow may have been greatest from the R 0450 diet, optimum feed intakes and milk yields were achieved on a diet that contained a
Schumaker, M. A.; Hurst, A. M.; Svensson, C. E.; Wu, C. Y.; Becker, J. A.; Cline, D.; Hackman, G.; Pearson, C. J.; Stoyer, M. A.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Barton, C. J.; Boston, A. J.; Boston, H. C.; Buchmann, L.; Churchman, R.; Cifarelli, F.; Colosimo, S. J.; Cooper, R. J.; Cross, D. S.; Dashdorj, D.; Demand, G. A.; Dimmock, M. R.; Djongolov, M.; Drake, T. E.; Finlay, P.; Gallant, A. T.; Garrett, P. E.; Gray-Jones, C.; Green, K. L.; Grint, A. N.; Grinyer, G. F.; Harkness, L. J.; Hayes, A. B.; Kanungo, R.; Leach, K. G.; Kulp, W. D.; Lisetskiy, A. F.; Lee, G.; Lloyd, S.; Maharaj, R.; Martin, J.-P.; Millar, B. A.; Moisan, F.; Morton, A. C.; Mythili, S.; Nelson, L.; Newman, O.; Nolan, P. J.; Orce, J. N.; Oxley, D. C.; Padilla-Rodal, E.; Phillips, A. A.; Porter-Peden, M.; Ressler, J. J.; Rigby, S. V.; Roy, R.; Ruiz, C.; Sarazin, F.; Scraggs, D. P.; Sumithrarachchi, C. S.; Triambak, S.; Waddington, J. C.; Walker, P. M.; Wan, J.; Whitbeck, A.; Williams, S. J.; Wong, J.; Wood, J. L.
2009-03-01
The TRIUMF-ISAC Gamma-Ray Escape Suppressed Spectrometer (TIGRESS) is a state-of-the-art γ-ray spectrometer being constructed at the ISAC-II radioactive ion beam facility at TRIUMF. TIGRESS will be comprised of twelve 32-fold segmented high-purity germanium (HPGe) clover-type γ-ray detectors, with BGO/CsI(Tl) Compton-suppression shields, and is currently operational at ISAC-II in an early-implementation configuration of six detectors. Results have been obtained for the first experiments performed using TIGRESS, which examined the A = 20, 21, and 29 isotopes of Na by Coulomb excitation.
Cool-season annual pastures with clovers to supplement wintering beef cows nursing calves
Directory of Open Access Journals (Sweden)
Gunter Stacey A
2012-07-01
Full Text Available Abstract In December of 3 years, 87 beef cows with nursing calves (594 ± 9.8 kg; calving season, September to November at side were stratified by body condition score, body weight, cow age, and calf gender and divided randomly into 6 groups assigned to 1 of 6 cool-season annual pastures (0.45 ha/cow that had been interseeded into a dormant common bermudagrass (Cynodon dactylon [L.] Pers./bahiagrass (Paspalum notatum Flugge sod. Pastures contained 1 of the following 3 seeding mixtures (2 pastures/mixture: 1 wheat (Triticum aestivum L. and ryegrass (Lolium multiflorum Lam., WRG, 2 wheat and ryegrass plus red clover (Trifolium pretense L., WRR, or 3 wheat and ryegrass plus white (Trifolium repens L. and crimson clovers (Trifolium incarnatum L., WRW. All groups had ad libitum access to grass hay (12% crude protein; 58% total digestible nutrients. The second week in December, cow estrous cycles were synchronized and artificially inseminated. In late December, a bull was placed with each group for 60-d. Data were analyzed with an analysis of variance using a mixed model containing treatment as the fixed effect and year as the random effect. Body weight and condition scores did not differ (P ≥ 0.27 among cows between February and June. Calf birth weights or average daily gain did not differ (P ≥ 0.17 among treatments; however, calves grazing pastures with clovers did tend (P = 0.06 to weigh more than calves grazing grass only. Weaning weight per cow exposed to a bull was greater (P = 0.02 for WRR and WRW than WRG. Cows grazing winter-annual pastures containing clovers tended to wean more calf body weight per cow exposed to a bull than cows grazing the grass only pastures.
Directory of Open Access Journals (Sweden)
Mohsen Hosseini
2015-03-01
Full Text Available BACKGROUND: Non-enzymatic glycosylation of hemoglobin is complications of diabetes. Antioxidant system imbalance can result in the emergence of free radicals’ destructive effects in the long-term. Red clover (Trifolium pratense L. and alfalfa (Medicago sativa L. contain isoflavonoids and have antioxidant activity. This experimental study evaluated the inhibitory activity of pure isoflavonoids (daidzein and genistein, red clover and alfalfa extracts on hemoglobin glycosylation. METHODS: This study was performed in Iran. Stock solution of hydroalcoholic extracts of red clover and alfalfa in concentrations of 1 and 10 g/100 ml and stock solution of daidzein and genistein in concentrations of 250 ng, 500 ng, 25 µg and 250 µg/100 ml were prepared as case groups. Control group was without hydroalcoholic extracts of plants and pure isoflavonoids. All experiments were performed in triplicate. Hemoglobin was prepared and antioxidant activities were investigated to estimate degree of nonenzymatic hemoglobin glycosylation. RESULTS: There was no significantly difference between used extracts (extract of red clover and alfalfa and control of the hemoglobin glycosylation but using daidzein (P = 0.046, 0.029 and 0.021, respectively and genistein (P = 0.034, 0.036 and 0.028 significantly inhibited (P < 0.050 this reaction in 25 µg/100 ml, 250 and 500 ng/100 ml concentrations when compared to control. in 25 µg/100 ml, 250 ng and 500 ng/100 ml concentrations percentage of inhibition were 32, 80 and 74.5% respectively with used of daidzein and were 21, 83 and 76% respectively with consumption of genistein. CONCLUSION: According to decrease of glycation of hemoglobin with isoflavonoids, two used plant in this study containing isoflavonoid may be useful on diabetes.
DEFF Research Database (Denmark)
Maraldo, Kristine; Schmelz, Rüdiger; Larsen, Thomas
2015-01-01
One objective in organic farming is to sustain the quality of the soil resource. Because enchytraeids are an important soil faunal component, they stand as bioindicators of soil quality. We tested this candidature in a field experiment on loamy sand soil with 1- and 4-year old grass-clover leys...... interactions among soil physical, chemical and biological properties suggest that enchytraeid abundance is not a feasible stand-alone indicator of management impacts on soil quality in temporary grass-clover leys but may candidate as one of several biological key parameters in more comprehensive soil quality...
International Nuclear Information System (INIS)
Baylis, J.P.; Cherrett, J.M.; Ford, J.B.
1986-01-01
Clover roots were labelled in the field with 32 P and the radioactive soil fauna were detected by autoradiography. The animals which consumed labelled clover roots were, in order of importance, earthworms (Aporrectodea longa, A. caliginosa and Lumbricus rubellus), weevil larvae, dipteran larvae (Bibio marci) and a few Collembola (family: Entomobryidae). (author)
Calibration of the new composite ''clover'' detector as a Compton polarimeter for the EUROGAM array
International Nuclear Information System (INIS)
Jones, P.M.; Beck, F.A.; Butler, P.A.; Duchene, G.; France, G. de; Hannachi, F.; Jones, G.D.
1995-01-01
The application of a composite Ge detector to the measurement of the linear polarisation of γ-rays has been investigated. The polarisation sensitivity of this device has been determined over the energy range 197-1368 keV. Comparison to a previous design of a similar detector has been made. (orig.)
Background intercomparison with escape-suppressed germanium detectors in underground mines
Energy Technology Data Exchange (ETDEWEB)
Szuecs, Tamas; Bemmerer, Daniel [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany)
2014-07-01
A key requirement for underground nuclear astrophysics experiments is the very low background level in germanium detectors underground. The reference for these purposes is the world's so far only underground accelerator laboratory for nuclear astrophysics, LUNA. LUNA is located deep underground in the Gran Sasso laboratory in Italy, shielded from cosmic rays by 1400 m of rock. The background at LUNA was studied in detail using an escape-suppressed Clover-type HPGe detector. Exactly the same detector was subsequently transported to the Felsenkeller underground laboratory in Dresden, shielded by 45 m of rock, and the background was shown to be only a factor of three higher than at LUNA when comparing the escape-suppressed spectra, with interesting consequences for underground nuclear astrophysics. As the next step of a systematic study of the effects of a combination of active and passive shielding on the cosmic ray induced background, this detector is now being brought to the ''Reiche Zeche'' mine in Freiberg/Sachsen, shielded by 150 m of rock. The data from the Freiberg measurement are shown and discussed.
A study of the red clover extract trinovin by ESR HPLC/MS and UVS
International Nuclear Information System (INIS)
Troup, G.; Hutton, D.; Hunter, C.; Hewitt, D.; Mulinacci, N.; Romani, A.; Pinelli, P.; Mancini, P.
1999-01-01
Full text: Trinovin is an extract of red clover, recently released on the dietary supplement market. It is recommended for 'Men's Health', because it contains the phenolics (isoflavones) genistein, biochanin, daidzein and formononetin, said to act as 'phytoestrogens', and is therefore a possible help in prostate gland problems. An Electron Spin Resonance (ESR) study (∼9.1Ghz, room temperature) revealed at least 3 different free radical lines, one with hyperfine structure, consistent with the listed molecules. Accordingly, HPLC/DAD (High Performance Liquid Chromatography/Diode Array Detector) and HPLC/Mass Spectroscopy analyses were performed in order to evaluate the quali-quantitative contents of flavonoidic compounds. The HPLC profile shows two main isoflavones and another three compounds, one of them being a quercetin glycoside. The quercetin glycosides are flavonoidic derivatives abundant in plant materials and present in wine. We can therefore say: even if the phytoestrogen properties claimed for Trinovin turn out to be less than hoped for, the antioxidants contained are very powerful, and so possibly helpful in protection against many diseases, including cancers, atherosclerosis, diabetic retinal bleeding, and non-alcoholic dementia
Stødkilde, Lene; Damborg, Vinni K; Jørgensen, Henry; Laerke, Helle N; Jensen, Søren K
2018-05-01
The present study aimed to evaluate the use of white clover as an alternative protein source for monogastrics. White clover plant and leaves were processed using a screw-press resulting in a solid pulp and a juice from which protein was acid-precipitated. The chemical composition of all fractions was determined and digestibility of dry matter (DM) and protein was assessed in an experiment with growing rats. Protein concentrates were produced with crude protein (CP) contents of 451 g kg -1 and 530 g kg -1 DM for white clover plant and leaves, respectively, and a pulp with CP contents of 313 and 374 g kg -1 DM from plant and leaves, respectively. The amino acid composition ranged from 4.72 to 6.49 g per 16 g of nitrogen (N) for lysine, 1.82-2.6 g per 16 g N for methionine and cysteine, and 3.66-5.24 g per 16 g N for threonine. True faecal digestibility of protein varied from 0.81 to 0.88, whereas DM digestibility was in the range 0.72-0.80. Methionine and cysteine were found to be limiting in all fractions, regardless of the reference group used. A high digestibility of white clover protein was found irrespective of the physical fractionation. Together with a well-balanced amino acid composition, this makes white clover a promising protein source for monogastrics. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.
Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover.
Fernández-Aparicio, Mónica; Bernard, Alexandre; Falchetto, Laurent; Marget, Pascal; Chauvel, Bruno; Steinberg, Christian; Morris, Cindy E; Gibot-Leclerc, Stephanie; Boari, Angela; Vurro, Maurizio; Bohan, David A; Sands, David C; Reboud, Xavier
2017-01-01
Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro , rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management.
Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover
Directory of Open Access Journals (Sweden)
Mónica Fernández-Aparicio
2017-05-01
Full Text Available Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro, rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management.
Directory of Open Access Journals (Sweden)
Izabela Jasicka-Misiak
2017-01-01
Full Text Available A case study of Polish Melilotus officinalis honey was presented for the first time. Gas chromatography–mass spectrometry (GC-MS (after steam distillation, Soxhlet extraction, ultrasonic solvent extraction, and solid phase extraction (SPE and targeted high performance liquid chromatography with a photodiode array detector (HPLC-PAD were applied to determine the characteristic components of honey. While ubiquitous in most honeys, carbohydrates, terpene derivatives, and phenylacetic acid dominated in the Soxhlet extracts (25.54% and in the application of SPE (13.04%. In addition, lumichrome (1.85% was found, and may be considered as a marker of this honey. Due to the presence of these compounds, Polish yellow sweet clover honey is similar to French lavender honeys. The major compounds determined in the methanolic extract were (+-catechine (39.7% and gallic acid (up to 30%, which can be regarded as specific chemical markers of the botanical origin of melilot honey. With respect to total phenolic and flavonoid contents, 1,1-diphenyl-2-picrylhydrazyl (DPPH assays were determined spectrophotometrically. The honey exhibited a moderate antioxidant activity, typical for light honeys, which correlates well with its phenolic and flavonoid composition.
Genetic variations between two ecotypes of Egyptian clover by inter ...
African Journals Online (AJOL)
Aghomotsegin
2015-06-10
Jun 10, 2015 ... Four Egyptian clover (Trifolium alexandrinum L) cultivars representing two ecotypes were used in the present study. Fahl cultivar is prevalent in whole Egypt and is good for single cut as it has poor regeneration ability, whereas Serw1, Giza6 and Gemmiza1 give 5-6 cuts of good fodder. Techniques based ...
Relationship between nitrogen cycling and nitrous oxide emission in grass-clover pasture
Ambus, P.
2005-01-01
The paper reports on a work assessing the relationship between gross N transformations in grass-clover soils and emissions of nitrous oxide. By this manner, the source strength of the biogenic processes responsible for nitrous oxide production is evaluated.
Kishor Bhattarai
2010-01-01
Western prairie clover [Dalea ornata (Douglas ex Hook.) Eaton & J. Wright] is a perennial legume that occurs in the northern Great Basin, Snake River Basin, and southern Columbia Plateau, whereas Searls prairie clover [Dalea searlsiae (A. Gray) Barneby], also a perennial legume, occurs in the southern Great Basin and surrounding areas. Understanding the genetic and...
Directory of Open Access Journals (Sweden)
Sergio Saia
Full Text Available Several studies, performed mainly in pots, have shown that arbuscular mycorrhizal symbiosis can mitigate the negative effects of water stress on plant growth. No information is available about the effects of arbuscular mycorrhizal symbiosis on berseem clover growth and nitrogen (N fixation under conditions of water shortage. A field experiment was conducted in a hilly area of inner Sicily, Italy, to determine whether symbiosis with AM fungi can mitigate the detrimental effects of drought stress (which in the Mediterranean often occurs during the late period of the growing season on forage yield and symbiotic N2 fixation of berseem clover. Soil was either left under water stress (i.e., rain-fed conditions or the crop was well-watered. Mycorrhization treatments consisted of inoculation of berseem clover seeds with arbuscular mycorrhizal spores or suppression of arbuscular mycorrhizal symbiosis by means of fungicide treatments. Nitrogen biological fixation was assessed using the 15N-isotope dilution technique. Arbuscular mycorrhizal symbiosis was able to mitigate the negative effect of water stress on berseem clover grown in a typical semiarid Mediterranean environment. In fact, under water stress conditions, arbuscular mycorrhizal symbiosis resulted in increases in total biomass, N content, and N fixation, whereas no effect of crop mycorrhization was observed in the well-watered treatment.
Saia, Sergio; Amato, Gaetano; Frenda, Alfonso Salvatore; Giambalvo, Dario; Ruisi, Paolo
2014-01-01
Several studies, performed mainly in pots, have shown that arbuscular mycorrhizal symbiosis can mitigate the negative effects of water stress on plant growth. No information is available about the effects of arbuscular mycorrhizal symbiosis on berseem clover growth and nitrogen (N) fixation under conditions of water shortage. A field experiment was conducted in a hilly area of inner Sicily, Italy, to determine whether symbiosis with AM fungi can mitigate the detrimental effects of drought stress (which in the Mediterranean often occurs during the late period of the growing season) on forage yield and symbiotic N2 fixation of berseem clover. Soil was either left under water stress (i.e., rain-fed conditions) or the crop was well-watered. Mycorrhization treatments consisted of inoculation of berseem clover seeds with arbuscular mycorrhizal spores or suppression of arbuscular mycorrhizal symbiosis by means of fungicide treatments. Nitrogen biological fixation was assessed using the 15N-isotope dilution technique. Arbuscular mycorrhizal symbiosis was able to mitigate the negative effect of water stress on berseem clover grown in a typical semiarid Mediterranean environment. In fact, under water stress conditions, arbuscular mycorrhizal symbiosis resulted in increases in total biomass, N content, and N fixation, whereas no effect of crop mycorrhization was observed in the well-watered treatment.
Blum, Oleg; Didyk, Nataliya; Pavluchenko, Nataliya; Godzik, Barbara
2011-01-01
Some modern agrochemicals with antioxidant potential were tested for their protective effect against ozone injury using clover and tobacco ozone-sensitive cultivars as model plants subjected to ambient ozone at two sites (Kyiv city in Ukraine and Szarów village in Poland). All used agrochemicals showed partial protective effects against ozone injury on clover and tobacco. Conducted studies confirmed the effectiveness of modern fungicides belonging to strobilurin group as protectants of sensit...
The dynamics of monolithic suspensions for advanced detectors: A 3-segment model
Energy Technology Data Exchange (ETDEWEB)
Piergiovanni, F; Campagna, E; Cesarini, E; Martelli, F; Vetrano, F; Vicere, A [Universita di Urbino, Via S.Chiara 27, 61029 Urbino (Italy); Lorenzini, M; Cagnoli, G; Losurdo, G, E-mail: piergiovanni@fi.infn.i [INFN, Istituto Nazionale di Fisica Nucleare, Sez. di Firenze, via G. Sansone 1, 50019 Sesto Fiorentino (Italy)
2010-05-01
In order to reduce the suspension thermal noise, the second generation GW interferometric detectors will employ monolithic suspensions in fused silica to hold the mirrors. The fibres are produced by melting and pulling apart a fused silica rod, obtaining a long thin wire with two thicker heads. The dynamics of such a fibre is in principle different from that of a cylindrical, regular fibre, because most of the deformation energy is stored in the neck region where the diameter is variable. This is an advantage, since adjusting the neck tapering, a thermoelastic noise cancellation effect can be obtained. Therefore, a careful study of the suspensions behavior is necessary to estimate the overall noise and to optimize the control strategy. To simplify the control design, a simple three segment model for the silica fibres has been developed, fully equivalent to the beam equation at low frequencies. The model, analytically proved for a regular cylindrical fibre, can be extended to a fibre with tapered necks, provided that the equivalent bending length is suitably measured. We developed a tool to measure the position of the bending point for each fibre, thus allowing to experimentally check the validity of the model. A numerical code has been written to solve the beam equation for wires with varying diameter. This code confirms the validity of the three segment model. Moreover, it is possible to extend the solution to higher frequencies thus computing the transfer function and the energy distribution of the suspension system and estimating the thermal noise contribution.
Crystallization and preliminary X-ray diffraction analysis of red clover necrotic mosaic virus
International Nuclear Information System (INIS)
Martin, Stanton L.; Guenther, Richard H.; Sit, Tim L.; Swartz, Paul D.; Meilleur, Flora; Lommel, Steven A.; Rose, Robert B.
2010-01-01
Virions of red clover necrotic mosaic virus have been purified and crystallized. The space group was determined to be I23, with unit-cell parameter a = 377.8 Å. The crystals diffracted to 4 Å resolution. Red clover necrotic mosaic virus (RCNMV) is a species that belongs to the Tombusviridae family of plant viruses with a T = 3 icosahedral capsid. RCNMV virions were purified and were crystallized for X-ray analysis using the hanging-drop vapor-diffusion method. Self-rotation functions and systematic absences identified the space group as I23, with two virions in the unit cell. The crystals diffracted to better than 4 Å resolution but were very radiation-sensitive, causing rapid decay of the high-resolution reflections. The data were processed to 6 Å in the analysis presented here
Cumulative effects of white clover residues on the changes in soil ...
African Journals Online (AJOL)
STORAGESEVER
2009-05-18
May 18, 2009 ... The residual effects of white clover on soil properties indicated a significant increase in saturation percentage (17–23%) and .... determined by leaching the soil with KCl followed by extraction of ...... accumulation, and oil quality of French basil. ... of the Final Workshop of the Farming System Integrated Pest.
An automatic gain matching method for {gamma}-ray spectra obtained with a multi-detector array
Energy Technology Data Exchange (ETDEWEB)
Pattabiraman, N.S.; Chintalapudi, S.N.; Ghugre, S.S. E-mail: ssg@alpha.iuc.res.in
2004-07-01
The increasing size of data sets from large multi-detector arrays makes the traditional approach to the pre-evaluation of the data difficult and time consuming. The pre-sorting involves detection and correction of the observed on-line drifts followed by calibration of the raw data. A new method for automatic detection and correction of these instrumental drifts is presented. An application of this method to the data acquired using a multi-Clover array is discussed.
An automatic gain matching method for γ-ray spectra obtained with a multi-detector array
International Nuclear Information System (INIS)
Pattabiraman, N.S.; Chintalapudi, S.N.; Ghugre, S.S.
2004-01-01
The increasing size of data sets from large multi-detector arrays makes the traditional approach to the pre-evaluation of the data difficult and time consuming. The pre-sorting involves detection and correction of the observed on-line drifts followed by calibration of the raw data. A new method for automatic detection and correction of these instrumental drifts is presented. An application of this method to the data acquired using a multi-Clover array is discussed
Effect of red clover on the microbial transformation of phenanthrene and octadecane in the soil
Nazarov, A. V.; Shestakova, E. A.; Anan'yina, L. N.
2017-08-01
The influence of red clover ( Trifolium pratense L.) plants on the decomposition of phenanthrene and octadecane in the soil has been studied. Effect of plant root mass on the abundance of hydrocarbondegrading bacteria, the composition of their communities, and the degradation of hydrocarbons in the soil has been revealed. Changes in the taxonomic composition of hydrocarbon-degrading bacteria under the effect of red clover are characterized by an increase in the abundance of species from the genera Acinetobacter, Kaistia, Novosphingobium, Pseudomonas, and Xanthomonas. A positive effect of the studied microbial-plant association on the degradation of octadecane and especially phenanthrene in the soil has been revealed.
Islam, Afsana; Mercer, Chris F; Leung, Susanna; Dijkwel, Paul P; McManus, Michael T
2015-01-01
The transcription of four members of the Kunitz proteinase inhibitor (KPI) gene family of white clover (Trifolium repens L.), designated as Tr-KPI1, Tr-KPI2, Tr-KPI4 and Tr-KPI5, was investigated at both local infection (roots) and systemic (leaf tissue) sites in white clover in response to infection with the clover root knot nematode (CRKN) Meloidogyne trifoliophila and the clover cyst nematode (CCN) Heterodera trifolii. Invasion by the CRKN resulted in a significant decrease in transcript abundance of Tr-KPI4 locally at both 4 days post-infection (dpi) and at 8 dpi, and an increase in transcription of Tr-KPI1 systemically at 8 dpi. In contrast, an increase in transcript abundance of all four Tr-KPI genes locally at 4 and 8 dpi, and an increase of Tr-KPI1, Tr-KPI2, and Tr-KPI5 at 8 dpi systemically was observed in response to infection with the CCN. Challenge of a resistant (R) genotype and a susceptible (S) genotype of white clover with the CCN revealed a significant increase in transcript abundance of all four Tr-KPI genes locally in the R genotype, while an increase in abundance of only Tr-KPI1, Tr-KPI2, and Tr-KPI5 was observed in the S genotype, and only at 4 dpi. The transcript abundance of a member of the1-AMINOCYCLOPROPANE-1-CARBOXYLATE (ACC) SYNTHASE gene family from white clover (Tr-ACS1) was significantly down-regulated locally in response to CRKN infection at 4 and 8 dpi and at 4 dpi, systemically, while abundance increased locally and systemically at 8 dpi in response to CCN challenge. Conversely, the abundance of the jasmonic acid (JA) signalling gene, CORONATINE-INSENSITIVE PROTEIN 1 from white clover (Tr-COI1) increased significantly at 8 dpi locally in response to CRKN infection, but decreased at 8 dpi in response to CCN infection. The significance of this differential regulation of transcription is discussed with respect to differences in infection strategy of the two nematode species.
Directory of Open Access Journals (Sweden)
f Hassanzadeh Aval
2012-02-01
Full Text Available Abstract In order to evaluate intercropping of summer savory (Satureja hortensis L. and Persian clover (Trifolium resupinatum L., an experiment was conducted in the Agricultural Research Station of Ferdowsi University of Mashhad in 2004 growing season. Treatments were sole cropping of Persian clover (eight rows, double-row intercropping of Persian clover and summer savory with 27, 40 and 80 plants.m-2 (eight rows and sole cropping of summer savory with 27, 40 and 80 plants m-2 (eight rows. For this purpose a complete randomized block design with 4 replications was used. Shoot and stem percentage of summer savory in sole crop treatments were significantly higher than in intercrop. In sole crop treatments, these parameters decreased by increasing plant density, in contrast to the intercrop. Leaf percentage and leaf and flower to stem ratio of summer savory in sole crop treatments were significantly lower than in intercrop. In sole crop treatments, these parameters were increased by increasing plant density, in contrast to intercrop. Effect of different treatments on essential oil percentage of summer savory was not significant. In sole cropping of Persian clover treatment, dry weight of vegetative organs and stem percentage of Persian clover in the first harvest, was lower than other treatments. By decreasing plant density these parameters were decreased in intercropping. In the second and third harvests a reversed pattern was observed. The highest Area Time Equivalent Ratio was obtained in intercropping of persian clover and summer savory with 27 plants.m-2. Keywords: Intercropping, Plant density, Satureja hortensis, Trifolium resupinatum, Essential oil percentage, Area Time Equivalent Ratio
Chu, Qiuhui; Shen, Yijie; Yuan, Meng; Gong, Mali
2017-12-01
Segmented Planar Imaging Detector for Electro-Optical Reconnaissance (SPIDER) is a cutting-edge electro-optical imaging technology to realize miniaturization and complanation of imaging systems. In this paper, the principle of SPIDER has been numerically demonstrated based on the partially coherent light theory, and a novel concept of adjustable baseline pairing SPIDER system has further been proposed. Based on the results of simulation, it is verified that the imaging quality could be effectively improved by adjusting the Nyquist sampling density, optimizing the baseline pairing method and increasing the spectral channel of demultiplexer. Therefore, an adjustable baseline pairing algorithm is established for further enhancing the image quality, and the optimal design procedure in SPIDER for arbitrary targets is also summarized. The SPIDER system with adjustable baseline pairing method can broaden its application and reduce cost under the same imaging quality.
Analysis of the soil food web structure under grass and grass clover
Eekeren, van N.J.M.; Smeding, F.W.; Vries, de F.T.; Bloem, J.
2006-01-01
The below ground biodiversity of soil organisms plays an important role in the functioning of the the soil ecosystem, and consequently the above ground plant production. The objective of this study is to investigate the effect of grass or grass-clover in combination with fertilisation on the soil
Effects of titanium dioxide nanoparticles on red clover and its rhizobial symbiont
Moll, Janine; Okupnik, Annette; Gogos, Alexander; Knauer, Katja; Bucheli, Thomas D.; Van Der Heijden, Marcel G A; Widmer, Franco
2016-01-01
Titanium dioxide nanoparticles (TiO2 NPs) are in consideration to be used in plant protection products. Before these products can be placed on the market, ecotoxicological tests have to be performed. In this study, the nitrogen fixing bacterium Rhizobium trifolii and red clover were exposed to two
Towards integrated pest management in red clover seed production.
Lundin, Ola; Rundlöf, Maj; Smith, Henrik G; Bommarco, Riccardo
2012-10-01
The development of integrated pest management is hampered by lack of information on how insect pest abundances relate to yield losses, and how pests are affected by control measures. In this study, we develop integrated pest management tactics for Apion spp. weevils (Coleoptera: Brentidae) in seed production of red clover, Trifolium pratense L. We tested a method to forecast pest damage, quantified the relationship between pest abundance and yield, and evaluated chemical and biological pest control in 29 Swedish red clover fields in 2008 and 2011. Pest inflorescence abundance, which had a highly negative effect on yield, could be predicted with pan trap catches of adult pests. In 2008, chemical control with typically one application of pyrethroids was ineffective both in decreasing pest abundances and in increasing yields. In 2011, when chemical control included applications of the neonicotinoid thiacloprid, pest abundances decreased and yields increased considerably in treated field zones. A post hoc analysis indicated that using pyrethroids in addition to thiacloprid was largely redundant. Infestation rates by parasitoids was higher and reached average levels of around 40% in insecticide treated field zones in 2011, which is a level of interest for biological pest control. Based on the data presented, an economic threshold for chemical control is developed, and guidelines are provided on minimum effective chemical pest control.
Forbs enhance productivity of unfertilised grass-clover leys and support low-carbon bioenergy
DEFF Research Database (Denmark)
Cong, Wen-Feng; Jing, Jingying; Rasmussen, Jim
2017-01-01
Intensively managed grasslands are dominated by highly productive grass-clover mixtures. Increasing crop diversity by inclusion of competitive forbs may enhance biomass production and sustainable biofuel production. Here we examined if one or all of three forbs (chicory, Cichorium intybus L.; car...
Ström, Petter; Petersson, Per; Rubel, Marek; Possnert, Göran
2016-10-01
A dedicated detector system for heavy ion elastic recoil detection analysis at the Tandem Laboratory of Uppsala University is presented. Benefits of combining a time-of-flight measurement with a segmented anode gas ionization chamber are demonstrated. The capability of ion species identification is improved with the present system, compared to that obtained when using a single solid state silicon detector for the full ion energy signal. The system enables separation of light elements, up to Neon, based on atomic number while signals from heavy elements such as molybdenum and tungsten are separated based on mass, to a sample depth on the order of 1 μm. The performance of the system is discussed and a selection of material analysis applications is given. Plasma-facing materials from fusion experiments, in particular metal mirrors, are used as a main example for the discussion. Marker experiments using nitrogen-15 or oxygen-18 are specific cases for which the described improved species separation and sensitivity are required. Resilience to radiation damage and significantly improved energy resolution for heavy elements at low energies are additional benefits of the gas ionization chamber over a solid state detector based system.
Modelling Gene Flow between Fields of White Clover with Honeybees as Pollen Vectors
DEFF Research Database (Denmark)
Løjtnant, Christina; Boelt, Birte; Clausen, Sabine Karin
2012-01-01
The portion-dilution model is a parametric restatement of the conventional view of animal pollination; it predicts the level of pollinator-mediated gene dispersal. In this study, the model was applied to white clover (Trifolium repens) and its most frequent pollinator, the honeybee (Apis mellifera......). One of the three parameters in the portion-dilution model is the mean number of flowers a pollinator visits in one foraging bout. An alternative method to estimate this parameter was developed that was not depending on pollinator hive-seeking behaviour. The new estimation method, based on nectar......% with an estimated 95% percentile of 70%. The results show that the European Union threshold limit of 0.9% GM admixture for food and feed will likely be exceeded at times and especially organic farmers that do not accept GM admixture and often have clover and clover–grass fields might face challenges with admixture...
DEFF Research Database (Denmark)
Wermuth, Kirsten Haugaard; Dupont, Yoko L.
2010-01-01
Red clover is a key floral ressource for bumblebees (Bombus spp.).We here investigate variation within and among red clover fields in species richness and abundance of Bombus spp. in addition to Apis mellifera. Bumblebee individuals were grouped into the following functional groups, based on castes...... and tongue length: (1) all queens, (2) all workers, (3) short-tongued workers and (4) long-tongued workers. In 14 study fields, no spatial or diurnal within-field differences were found in abundances of bee groups. However, seasonal differences were detected. On average 6.3±0.6 Bombus spp. were observed...
ADC common noise correction and zero suppression in the PIBETA detector
International Nuclear Information System (INIS)
Frlez, E.; Pocanic, D.; Ritt, S.
2001-01-01
We describe a simple procedure for reducing Analog-to-Digital Converter (ADC) common noise in modular detectors that does not require additional hardware. A method using detector noise groups should work well for modular particle detectors such as segmented electromagnetic calorimeters, plastic scintillator hodoscopes, cathode strip wire chambers, segmented active targets, and the like. We demonstrate a 'second pedestal noise correction' method by comparing representative ADC pedestal spectra for various elements of the PIBETA detector before and after the applied correction
1986-07-01
types where they are common (Kohn and Mooty 1971). Rumen analyses of white-tailed deer in Montana showed that forbs comprised 80% of summer samples...frequency of occurrence in deer rumens collected from January through March in the Northern Black Hills. Bluegrass- white clover meadows are also...CAUTIONS AND LIMITATIONS White clover, like most legumes, occasionally causes bloat in animals, particularly cattle and sheep that have overfilled
Effects of oil sands effluent on cattail and clover: photosynthesis and the level of stress proteins
Energy Technology Data Exchange (ETDEWEB)
Crowe, A.U.; Han, B.; Kermode, A.R.; Bendell-Young, L.I.; Plant, A.L. [Simon Fraser University, Burnaby (Canada). Dept. of Biological Sciences
2001-07-01
The oil sands industry located in northeastern Alberta, Canada, generates large volumes of effluent characterized by a high level of dissolved ions and naphthenic acids. The dikes used to store the effluent seep, creating wetlands which are subsequently invaded by obligate wetland flora such as cattail (Typha latifolia L.). The appearance of these wetlands prompted the oil sands industry to consider wetlands as part of their reclamation strategy. However, to ensure long-term viability of such wetlands, the response of the flora to the industrial effluent needed to be determined. To this end, apparent photosynthesis (APS), the level of ribulose-1,5-bisphosphate carboxylase (RuBisCo) large subunit, dehydrin-related polypeptides, and protein disulphide isomerase (PDI) were evaluated in cattail and alsike clover plants (Trifolium hybridum L.) exposed to the oil sands effluent. APS measured in plants impacted by oil sands effluent was significantly higher than that of plants in the non-impacted off-site location. Among the on-site locations, plants growing in the natural wetlands site had higher APS compared to all other sites. The level of RuBisCo was not increased in cattail or clover growing in effluent-contaminated sites indicating that enhanced photosynthesis was not due to greater levels of this enzyme. Dehydrin-related polypeptides were detected only in the roots of cattail and were absent in clover. The polypeptide profile was altered in cattail exposed to oil sands effluent indicating that they were responding to an osmotic stress. The level of PDI was unaffected in the leaves of cattail regardless of the nature of the effluent to which they were exposed. Overall, the data indicate that cattail and clover are adapted to the oil sands effluent, although further studies are needed to assess their long-term ability to survive in the presence of this anthropogenic stress. (Author)
The "clover technique" as a novel approach for correction of post-traumatic tricuspid regurgitation.
Alfieri, O; De Bonis, M; Lapenna, E; Agricola, E; Quarti, A; Maisano, F
2003-07-01
To describe a novel technique, named "clover," to correct complex post-traumatic tricuspid valve lesions. Five patients with severe post-traumatic tricuspid insufficiency underwent valve reconstruction with the clover technique, a new surgical approach that consists of stitching together the middle point of the free edges of the tricuspid leaflets, producing a clover-shaped valve. The mechanism of tricuspid regurgitation was complex in all patients, and right ventricular function was always moderately to severely depressed. An echocardiographic study was performed after cardiopulmonary bypass, at discharge, and at follow-up. Cardiopulmonary bypass time was 32 +/- 6.3 minutes and crossclamp time was 23 +/- 7.4. There was no hospital mortality or morbidity. Intraoperative transesophageal and predischarge transthoracic echocardiography showed perfect results in all patients. No late deaths occurred. At the latest follow-up, extending to 14.2 months (mean 11.3; median 12.4), all patients were asymptomatic (New York Heart Association class I) with trivial (2 patients) or no residual regurgitation (3 patients) on 2-dimensional echocardiogram. No transvalvular gradient was revealed in any patient. A significant reduction of the right ventricular end-diastolic dimensions was noted as well (from 54 +/- 7.1 mm to 40 +/- 7.5 mm, P tricuspid valve repair in case of severe traumatic tricuspid valve insufficiency, leading to very satisfactory mid-term results even in the presence of complex lesions or dilatation and deterioration of the right ventricle.
Honeybees tolerate cyanogenic glucosides from clover nectar and flowers
DEFF Research Database (Denmark)
Lecocq, Antoine; Green, Amelia Ann; Pinheiro de Castro, Érika Cristina
2018-01-01
Honeybees (Apis mellifera) pollinate flowers and collect nectar from many important crops. White clover (Trifolium repens) is widely grown as a temperate forage crop, and requires honeybee pollination for seed set. In this study, using a quantitative LC-MS (Liquid Chromatography-Mass Spectrometry...... indicates that plant secondary metabolites found in nectar may protect pollinators from disease or predators. In a laboratory survival study with chronic feeding of secondary metabolites, we show that honeybees can ingest the cyanogenic glucosides linamarin and amygdalin at naturally occurring...
Silicon Drift Detectors - A Novel Technology for Vertex Detectors
Lynn, D.
1996-10-01
Silicon Drift Detectors (SDD) are novel position sensing silicon detectors which operate in a manner analogous to gas drift detectors. Single SDD's were shown in the CERN NA45 experiment to permit excellent spatial resolution (pseudo-rapidity. Over the last three years we undertook a concentrated R+D effort to optimize the performance of the detector by minimizing the inactive area, the operating voltage and the data volume. We will present test results from several wafer prototypes. The charge produced by the passage of ionizing particles through the bulk of the detectors is collected on segmented anodes, with a pitch of 250 μm, on the far edges of the detector. The anodes are wire-bonded to a thick film multi-chip module which contains preamplifier/shaper chips and CMOS based switched capacitor arrays used as an analog memory pipeline. The ADC is located off-detector. The complete readout chain from the wafer to the DAQ will be presented. Finally we will show physics performance simulations based on the resolution achieved by the SVT prototypes.
Rocco, Francesco; Cozzi, Luigi Alberto; Cozzi, Gabriele
2015-07-01
To use triphasic multi-detector computed tomography (MDCT) to study the renal segmental arterial anatomy and its relationship with the urinary tract to plan nephron-sparing surgery (NSS). One hundred and fifty nine patients underwent abdominal contrast-enhanced MDCT. We evaluated renal arteries and parenchymal vasculature. In 61 patients, the arteries and the urinary tract were represented simultaneously. 86.60% presented a single renal artery; 13.4%, multiple arteries. All single renal arteries divided into anterior and posterior branch before the hilum. The anterior artery branched into a superior, middle, and inferior branch. In 43.14%, the inferior artery arose before the others; in 45.75%, the superior artery arose before the others; in 9.80%, the branches shared a common trunk. In 26.80%, the posterior artery supplies the entire posterior surface; in 73.20%, it ends along the inferior calyx. In 96.73%, the upper pole was vascularized by the anterior superior branch and the posterior artery: the "tuning fork". MDCT showed four vascular segments in 96.73% and five in 3.27%. MDCT showed two avascular areas: the first along the projection of the inferior calyx on the posterior aspect, the second between the branches of the "tuning fork". The arterial phase provides the arterial tree representation; the delayed phase shows arteries and urinary tract simultaneously. MDCT provides a useful representation of the renal anatomy prior to intervascular-intrarenal NSS.
NUTRITIVE VALUES OF SOME ANNUAL CLOVERS (Trifolium sp. AT DIFFERENT GROWTH STAGES
Directory of Open Access Journals (Sweden)
A TEKELI
2006-05-01
Full Text Available This study was conducted between the years of 2001-2002 in the experimental area and laboratory of Field Crops Department of Agriculture Faculty in Trakya University, Tekirdağ (Turkey. Five different clovers [Persian (Trifolium resupinatum L. var. majus Boiss., Mediterranean (T. spumosum L., narrow-leaved (T. angustifolium L., hedgehog (T. echinatum M. Bieb. and lappa (T. lappaceum L. clovers] were used. Each plot consisted of 8 rows with a length of 5 m. Row spacing of 30 cm and sowing rate of 10 kg ha-1 were used. Sowing times were on 2.25.2001 and on 2.28.2002. Plots were not irrigated and fertilized after sown and harvest. One cut was taken in both years at 4 growing stages such as pre-bud, pre-bloom, 50% bloom and full-bloom. The central 1 m-2 sections was cut at ground level for dry matter. Approximately 500g samples were dried at 55 °C for 24 hours and stored for one day at room temperature then found dry matter. Crude protein (% was determined by Kjeldahl method.
Schils, R.L.M.; Boxem, T.; Jagtenberg, C.J.; Verboom, M.C.
2000-01-01
The performance of a white clover based dairy system in comparison with a grass/fertiliser-N system was studied during three years. Both systems had 59 cows, plus young stock, on an area of 40.6 ha for grass/clover and 34.4 ha for grass/fertiliser-N. During the grazing season, the cows in both
Kishor Bhattarai; Shaun Bushman; Douglas A. Johnson; John G. Carman
2011-01-01
Few North American legumes are available for use in rangeland revegetation in the western USA, but Searls prairie clover [Dalea searlsiae (A. Gray) Barneby] is one that holds promise. Commercial-scale seed production of this species could address the issues of unreliable seed availability and high seed costs associated with its wildland seed collection. To evaluate its...
Directory of Open Access Journals (Sweden)
A. VANHATALO
2008-12-01
Full Text Available The study was conducted to evaluate effects of silage type (grass-red clover vs. pure grass and grain supplement (oats vs. barley on rumen fermentation, post-ruminal nutrient flows, diet digestion and milk production. Four primiparous Finnish Ayrshire cows fitted with cannulae in the rumen and duodenum were used in a 4 × 4 Latin square experiment with four 28-d experimental periods and 2 × 2 factorial arrangements of treatments. Using red clover-containing (40% silage rather than pure grass silage had minor effects on rumen fermentation or diet digestion but increased non-ammonia nitrogen (N flow in terms of increased flows of microbial and dietary N entering to the small intestine. This was reflected as a reduced ruminal N degradability on grass-red clover diets. Furthermore, grass-red clover diets in comparison to grass silage diets increased milk lactose concentration and yields of milk, protein and lactose. Feeding oats in replacement for barley had minor effects on rumen fermentation or post-ruminal non-ammonia N flows but reduced digestibility of organic matter and neutral detergent fibre in the diet. Using oats rather than barley increased yields of milk and lactose but reduced milk protein concentration. Oats also increased proportions of C18:0 and C18:1 in milk fat and reduced those of C10:0 to C16:0. It is concluded that inclusion of red clover and replacement of barley with oats in grass silage based diets have beneficial effects in dairy cow production.;
Cytoskeleton-amyloplast interactions in sweet clover
Guikema, J. A.; Hilaire, E.; Odom, W. R.; Spooner, B. S. (Principal Investigator)
1993-01-01
The distribution of organelles within columella cells of sweet clover was examined by transmission electron microscopy following growth under static or clinorotating conditions. A developmentally conditioned polarity was observed, with a proximal location of the nucleus and a distal accumulation of the endoplasmic reticulum. This polarity was insensitive to clinorotation. In contrast, clinorotation altered the location of amyloplasts. Application of cytoskeletal poisons (colchicine, cytochalasin D, taxol, and phalloidin), especially during clinorotation, had interesting effects on the maintenance of columella cell polarity, with a profound effect on the extent, location, and structure of the endoplasmic reticulum. The site of cytoskeletal interactions with sedimenting amyloplasts is thought to be the amyloplast envelope. An envelope fraction, having over 17 polypeptides, was isolated using immobilized antibody technology, and will provide a means of assessing the role of specific peptides in cytoskeleton/amyloplast interactions.
Design and development of a silicon-segmented detector for 2D dose measurements in radiotherapy
Energy Technology Data Exchange (ETDEWEB)
Menichelli, David [Department of Clinical Phisiopathology, University of Florence, v.le Morgagni, 85-50134 Florence (Italy); INFN, Florence division, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy)], E-mail: david.menichelli@cern.ch; Bruzzi, Mara [Department of Energetics, University of Florence, via S. Marta, 3-50139 Florence (Italy); INFN, Florence division, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Bucciolini, Marta; Talamonti, Cinzia; Casati, Marta; Marrazzo, Livia [Department of Clinical Phisiopathology, University of Florence, v.le Morgagni, 85-50134 Florence (Italy); INFN, Florence division, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Tesi, Mauro [Department of Energetics, University of Florence, via S. Marta, 3-50139 Florence (Italy); Piemonte, Claudio; Pozza, Alberto; Zorzi, Nicola [ITC-irst, via Sommarive, 18-38050 Trento (Italy); Brianzi, Mirko [INFN, Florence division, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); De Sio, Antonio [Department of Astronomy and Space Science, University of Florence, L.go E. Fermi, 2-50125 Florence (Italy)
2007-12-11
Modern radiotherapy treatment techniques, such as intensity Modulated Radiation Therapy (IMRT) and protontherapy, require detectors with specific features, usually not available in conventional dosimeters. IMRT dose measurements, for instance, must face non-uniform beam fluences as well as a time-varying dose rate. Two-dimensional detectors present a great interest for dosimetry in beams with steep dose gradients, but they must satisfy a number of requirements and, in particular, they must exhibit high spatial resolution. With the aim of developing a dosimetric system adequate for 2D pre-treatment dose verifications, we designed a modular dosimetric device based on a monolithic silicon-segmented module. State and results of this work in progress are described in this article. The first 441 pixels, 6.29x6.29 cm{sup 2} silicon module has been produced by ion implantation on a 50 {mu}m thick p-type epitaxial layer. This sensor has been connected to a discrete readout electronics performing current integration, and has been tested with satisfactory results. In the final configuration, nine silicon modules will be assembled together to cover an area close to 20x20 cm{sup 2} with 3969 channels. In this case, the readout electronics will be based on an ASIC capable to read 64 channels by performing current-to-frequency conversion.
Mia, S.; van Groeningen, J.W.; Van de Voorde, T.F.J.; Oram, N.J.; Bezemer, T.M.; Mommer, Liesje; Jeffery, S.
2014-01-01
Increased biological nitrogen fixation (BNF) by legumes has been reported following biochar application to soils, but the mechanisms behind this phenomenon remain poorly elucidated. We investigated the effects of different biochar application rates on BNF in red clover (Trifolium pratense L.). Red
A mobile antineutrino detector with plastic scintillators
International Nuclear Information System (INIS)
Kuroda, Y.; Oguri, S.; Kato, Y.; Nakata, R.; Inoue, Y.; Ito, C.; Minowa, M.
2012-01-01
We propose a new type segmented antineutrino detector made of plastic scintillators for the nuclear safeguard application. A small prototype was built and tested to measure background events. A satisfactory unmanned field operation of the detector system was demonstrated. Besides, a detailed Monte Carlo simulation code was developed to estimate the antineutrino detection efficiency of the detector.
Characterization and calibration of radiation-damaged double-sided silicon strip detectors
Energy Technology Data Exchange (ETDEWEB)
Kaya, L. [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Vogt, A., E-mail: andreas.vogt@ikp.uni-koeln.de [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Reiter, P.; Birkenbach, B.; Hirsch, R.; Arnswald, K.; Hess, H.; Seidlitz, M.; Steinbach, T.; Warr, N.; Wolf, K. [Institut für Kernphysik, Universität zu Köln, D-50937 Köln (Germany); Stahl, C.; Pietralla, N. [Institut für Kernphysik, Technische Universität Darmstadt, D-64291 Darmstadt (Germany); Limböck, T.; Meerholz, K. [Physikalische Chemie, Universität zu Köln, D-50939 Köln (Germany); Lutter, R. [Maier-Leibnitz-Laboratorium, Ludwig-Maximilians-Universität München, D-85748 Garching (Germany)
2017-05-21
Double-sided silicon strip detectors (DSSSD) are commonly used for event-by-event identification of charged particles as well as the reconstruction of particle trajectories in nuclear physics experiments with stable and radioactive beams. Intersecting areas of both p- and n-doped front- and back-side segments form individual virtual pixel segments allowing for a high detector granularity. DSSSDs are employed in demanding experimental environments and have to withstand high count rates of impinging nuclei. The illumination of the detector is often not homogeneous. Consequently, radiation damage of the detector is distributed non-uniformly. Position-dependent incomplete charge collection due to radiation damage limits the performance and lifetime of the detectors, the response of different channels may vary drastically. Position-resolved charge-collection losses between front- and back-side segments are investigated in an in-beam experiment and by performing radioactive source measurements. A novel position-resolved calibration method based on mutual consistency of p-side and n-side charges yields a significant enhancement of the energy resolution and the performance of radiation-damaged parts of the detector.
Correction for hole trapping in AGATA detectors using pulse shape analysis
Energy Technology Data Exchange (ETDEWEB)
Bruyneel, B. [CEA Saclay, DSM/IRFU/SPhN, Gif-sur-Yvette Cedex (France); Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Birkenbach, B.; Eberth, J.; Hess, H.; Pascovici, Gh.; Reiter, P.; Wiens, A. [Universitaet zu Koeln, Institut fuer Kernphysik, Koeln (Germany); Bazzacco, D.; Farnea, E.; Michelagnoli, C.; Recchia, F. [INFN, Sezione di Padova, Padova (Italy); Collaboration: for the AGATA Collaboration
2013-05-15
Data from the highly segmented High-Purity Germanium (HPGe) detectors of the AGATA spectrometer show that segments are more sensitive to neutron damage than the central core contact. Calculations on the collection efficiency of charge carriers inside the HPGe detector were performed in order to understand this phenomenon. The trapping sensitivity, an expression based on the collection efficiencies for electrons and holes, is put forward to quantify the effect of charge carrier trapping. The sensitivity is evaluated for each position in the detector volume with respect to the different electrodes and the collected charge carrier type. Using the position information obtained by pulse shape analysis from the position-sensitive AGATA detectors, it is possible to correct for the energy deficit employing detector specific sensitivity values. We report on the successful correction of the energy peaks from heavily neutron-damaged AGATA detectors for core and segment electrode signals. The original energy resolution can optimally be recovered up to a certain quantifiable limit of degradation due to statistical fluctuations caused by trapping effects. (orig.)
Segmented Monolithic Germanium Detector Arrays for X-ray Absorption Spectroscopy. Final Report
International Nuclear Information System (INIS)
Hull, Ethan L.
2011-01-01
The experimental results from the Phase I effort were extremely encouraging. During Phase I PHDs Co. made the first strides toward a new detector technology that could have great impact on synchrotron x-ray absorption (XAS) measurements, and x-ray detector technology in general. Detector hardware that allowed critical demonstration measurements of our technology was designed and fabricated. This new technology allows good charge collection from many pixels on a single side of a multi-element monolithic germanium planar detector. The detector technology provides 'dot-like' collection electrodes having very low capacitance. The detector technology appears to perform as anticipated in the Phase I proposal. In particular, the 7-pixel detector studied showed remarkable properties; making it an interesting example of detector physics. The technology is enabled by the use of amorphous germanium contact technology on germanium planar detectors. Because of the scalability associated with the fabrication of these technologies at PHDs Co., we anticipate being able to supply larger detector systems at significantly lower cost than systems made in the conventional manner.
Phenotypic and genetic characterization of western prairie clover collections from the western USA
Kishor Bhattarai; B. Shaun Bushman; Douglas A. Johnson; John G. Carman
2010-01-01
Few North American legumes are available for rangeland revegetation in the semiarid western United States. Western prairie clover (Dalea ornata [Douglas ex Hook.] Eaton & J. Wright) is a perennial legume with desirable forage characteristics and is distributed in the northern Great Basin, Snake River Basin, and southern Columbia Plateau. Understanding the...
Relationships between Nitrate and Oxygen Supply in Symbiotic Nitrogen Fixation by White Clover
DEFF Research Database (Denmark)
Minchin, F. R.; Ines Minguez, M.; Sheedy, J. E.
1986-01-01
Exposure of mature, nodulated plants of white clover (Trifolium repens) cv. Blanca to 330 mg dm−3 NO3-N for 8 d caused nitrogenase activity per plant to decrease by 80%. Total nodulated root respiration was not significantly affected but analysis of its components showed an 81% decrease in nitrog...
Parity assignments in 140Ce up to 7 MeV using Compton polarimetry
International Nuclear Information System (INIS)
Buessing, M. A.; Elvers, M.; Endres, J.; Hasper, J.; Zilges, A.; Fritzsche, M.; Lindenberg, K.; Mueller, S.; Savran, D.; Sonnabend, K.
2008-01-01
Parity quantum numbers of J=1 states up to 7 MeV in the region of the Pygmy Dipole Resonance in 140 Ce were determined model independently by combining the methods of Nuclear Resonance Fluorescence and Compton polarimetry. For the first time the well-established method of Compton polarimetry was applied at such high energies. The experiment was performed using a fourfold segmented HPGe clover detector for the detection of the scattered photons. For all investigated dipole transitions asymmetries are found which correspond to negative parity of the excited states
Design, calibration, and performance of the MINERvA detector
Energy Technology Data Exchange (ETDEWEB)
Aliaga, L. [Department of Physics, College of William and Mary, Williamsburg, VA 23187 (United States); Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Apartado 1761, Lima, Perú (Peru); Bagby, L.; Baldin, B. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Baumbaugh, A. [Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Apartado 1761, Lima, Perú (Peru); Bodek, A.; Bradford, R. [University of Rochester, Rochester, NY 14610 (United States); Brooks, W.K. [Departamento de Física, Universidad Técnica Federico Santa María, Avda. España 1680, Casilla 110-V, Valparaíso (Chile); Boehnlein, D. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Boyd, S. [Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Budd, H. [University of Rochester, Rochester, NY 14610 (United States); Butkevich, A. [Institute for Nuclear Research of the Russian Academy of Sciences, 117312 Moscow (Russian Federation); Martinez Caicedo, D.A.; Castromonte, C.M. [Hampton University, Department of Physics, Hampton, VA 23668 (United States); Christy, M.E. [Department of Physics, University of Minnesota – Duluth, Duluth, MN 55812 (United States); Chvojka, J. [University of Rochester, Rochester, NY 14610 (United States); Motta, H. da [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, Rio de Janeiro, RJ 22290-180 (Brazil); and others
2014-04-11
The MINERvA experiment is designed to perform precision studies of neutrino-nucleus scattering using ν{sub μ} and ν{sup ¯}{sub μ} neutrinos incident at 1–20 GeV in the NuMI beam at Fermilab. This article presents a detailed description of the MINERvA detector and describes the ex situ and in situ techniques employed to characterize the detector and monitor its performance. The detector is composed of a finely segmented scintillator-based inner tracking region surrounded by electromagnetic and hadronic sampling calorimetry. The upstream portion of the detector includes planes of graphite, iron and lead interleaved between tracking planes to facilitate the study of nuclear effects in neutrino interactions. Observations concerning the detector response over sustained periods of running are reported. The detector design and methods of operation have relevance to future neutrino experiments in which segmented scintillator tracking is utilized.
Directory of Open Access Journals (Sweden)
Paolo Benincasa
2012-04-01
Full Text Available Most of research on intercrops evaluate performances and interference between species on the basis of final yield, while little knowledge is available on the interference in early stages and at the root level, at least for cultivated intercrops. In fact, in the few studies on this subject species are often combined minding at experimental needs (e.g. common substrate, temperature and water requirements, easy root separation more than at their actual use in the farm. The present work evaluates interspecific interference during early developmental stages for two intercrops of agricultural interest: soft wheat-faba bean and rapeseed-squarrosum clover. Improving this knowledge would help intercrop growth modelling and rational cultivation. The experiments were carried out on soft wheat (Triticum aestivum, faba bean (Vicia faba var. minor, rapeseed (Brassica napus var. oleifera and squarrosum clover (Trifolium squarrosum, germinated and grown until 32 days after sowing (DAS as one-species stands or as wheat/faba bean and rapeseed/squarrosum clover intercrops, with different densities and proportions for the two species in each couple. Germination was studied in controlled-temperature chamber, plantlet growth was studied on pots in the greenhouse. During germination no interspecific interference was observed for both wheat/faba bean and rapeseed/squarrosum clover intercrops. During plantlet growth, interspecific interference occurred in both intercrops causing variations in whole plant and root dry matter accumulation. In the wheat/faba bean intercrop each species suffered from the competitive effect of the companion species and faba bean was the dominant species when present in lower proportion than wheat. The unexpectedly high aggressivity of faba bean may be explained either with the greater seed size that could have represented an initial advantage within the short duration of the experiment or with the competition towards wheat for substrate N
Limitations on energy resolution of segmented silicon detectors
Wiącek, P.; Chudyba, M.; Fiutowski, T.; Dąbrowski, W.
2018-04-01
In the paper experimental study of charge division effects and energy resolution of X-ray silicon pad detectors are presented. The measurements of electrical parameters, capacitances and leakage currents, for six different layouts of pad arrays are reported. The X-ray spectra have been measured using a custom developed dedicated low noise front-end electronics. The spectra measured for six different detector layouts have been analysed in detail with particular emphasis on quantitative evaluation of charge division effects. Main components of the energy resolution due to Fano fluctuations, electronic noise, and charge division, have been estimated for six different sensor layouts. General recommendations regarding optimisation of pad sensor layout for achieving best possible energy resolution have been formulated.
DEFF Research Database (Denmark)
Schulze, Anne-Katrine Skovsted; Weisbjerg, Martin Riis; Nørgaard, Peder
2014-01-01
intake (PRumination time per kg DM intake (Pcontents (Prumination with greater...... NDF content (Prumination time increased with greater NDF content (Pcontent (P...The objective of this study was to assess effects of feed intake and NDF content of highly digestible grass-clover silage on chewing behavior, fecal particle size distribution and apparent digestibility in restrictively fed heifers. Four grass-clover silages (Lolium perenne, Trifolium pratense...
DEFF Research Database (Denmark)
Kusliene, Gedrime; Rasmussen, Jim; Kuzyakov, Yakov
2014-01-01
and actinomycetes was unaffected by plant species, but pool of Gram-negative and Gram-positive bacteria was greater under white clover at the 10 percent significance level. In the short term, microorganisms more actively utilised fresh exudates (13C-labelled) of ryegrass than of white clover. We expected ryegrass...... microbial groups in soil under white clover (Trifolium repens L.) and ryegrass (Lolium perenne L.) following leaf-labelling with 13C-bicarbonate and 15N-urea. In this way microbial N and 15N and the composition of PLFAs reflect the medium-term (two months) response of microorganisms to rhizodeposits......, whereas the 13C-label of the PLFAs reflects the short-term (one week) utilisation of root exudates following labelling of shoots. In the medium term, microbial biomass N and 15N were greater under the ryegrass, whereas total PLFA was higher under white clover. The relative abundance of fungi...
DEFF Research Database (Denmark)
Vinther, F.P.; Jensen, E.S.
2000-01-01
The input of Nitrogen (N) through symbiotic N-2 fixation (SNF) in grass-clover mixtures was determined in an organic cropping. system for grazing during 3 years. The mixture of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) was established by undersowing in spring...... barley (Hordeum vulgare L.) and maintained subsequently for two production years. Dinitrogen fixation was determined using the N-15 isotope dilution techniques and two labelling procedures. Using either pre-labelling of the soil with immobilisation of the N-15 by addition of a carbon source before...
Concrete Image Segmentation Based on Multiscale Mathematic Morphology Operators and Otsu Method
Directory of Open Access Journals (Sweden)
Sheng-Bo Zhou
2015-01-01
Full Text Available The aim of the current study lies in the development of a reformative technique of image segmentation for Computed Tomography (CT concrete images with the strength grades of C30 and C40. The results, through the comparison of the traditional threshold algorithms, indicate that three threshold algorithms and five edge detectors fail to meet the demand of segmentation for Computed Tomography concrete images. The paper proposes a new segmentation method, by combining multiscale noise suppression morphology edge detector with Otsu method, which is more appropriate for the segmentation of Computed Tomography concrete images with low contrast. This method cannot only locate the boundaries between objects and background with high accuracy, but also obtain a complete edge and eliminate noise.
Optimized high energy resolution in γ-ray spectroscopy with AGATA triple cluster detectors
Energy Technology Data Exchange (ETDEWEB)
Wiens, Andreas
2011-06-20
The AGATA demonstrator consists of five AGATA Triple Cluster (ATC) detectors. Each triple cluster detector contains three asymmetric, 36-fold segmented, encapsulated high purity germanium detectors. The purpose of the demonstrator is to show the feasibility of position-dependent γ-ray detection by means of γ-ray tracking, which is based on pulse shape analysis. The thesis describes the first optimization procedure of the first triple cluster detectors. Here, a high signal quality is mandatory for the energy resolution and the pulse shape analysis. The signal quality was optimized and the energy resolution was improved through the modification of the electronic properties, of the grounding scheme of the detector in particular. The first part of the work was the successful installation of the first four triple cluster detectors at INFN (National Institute of Nuclear Physics) in Legnaro, Italy, in the demonstrator frame prior to the AGATA commissioning experiments and the first physics campaign. The four ATC detectors combine 444 high resolution spectroscopy channels. This number combined with a high density were achieved for the first time for in-beam γ-ray spectroscopy experiments. The high quality of the ATC detectors is characterized by the average energy resolutions achieved for the segments of each crystal in the range of 1.943 and 2.131 keV at a γ-ray energy of 1.33 MeV for the first 12 crystals. The crosstalk level between individual detectors in the ATC is negligible. The crosstalk within one crystal is at a level of 10{sup -3}. In the second part of the work new methods for enhanced energy resolution in highly segmented and position sensitive detectors were developed. The signal-to-noise ratio was improved through averaging of the core and the segment signals, which led to an improvement of the energy resolution of 21% for γ-energies of 60 keV to a FWHM of 870 eV. In combination with crosstalk correction, a clearly improved energy resolution was
Design of large size segmented GEM foils and Drift PCB for CBM MUCH
International Nuclear Information System (INIS)
Saini, J.; Dubey, A.K.; Chattopadhyay, S.
2016-01-01
Triple GEM (Gas Electron Multiplier), sector shaped detectors will be used for Muon tracking in the Compressed Baryonic Matter (CBM) experiment at Anti-proton Ion Research (FAIR) facility at Darmstadt, Germany. The sizes of the detectors modules in the Muon Chambers (MUCH) are of the order of 1 meter with active area of about 75cms. Progressive pad geometry is chosen for the readout from these detectors. In construction of these chambers, three GEM foils are stacked on top of each other in a 3/2/2/2 gap configuration. The GEM foils are double layered copper clad 50μm thin Kapton foil. Each GEM foil has millions of holes on it. Foils of large surface area are prone to damages due to discharges owing to the high capacitance of the foil. Hence, these foils have their top surfaces divided into segments of about 100 sq.cm. Further segmentation may be necessary when there are high rate requirements, as in the case of CBM. For the GEM foils of CBM MUCH, a 24 segment layout has been adopted. Short-circuit in any of the GEM-holes will make entire foil un-usable. To reduce such occurrences, segment to segment isolation using opto-coupler in series with the GEM-foil segments has been introduced. Hence, a novel design for GEM chamber drift-PCB and foils has been made. In this scheme, each segment is powered and controlled individually. At the same time, the design takes into account, the space constraints, not only in x-y plane, but also in the z, due to compact assembly of MUCH detector layers
Monitoring of absolute mirror alignment at COMPASS RICH-1 detector
Alexeev, M.; Birsa, R.; Bradamante, F.; Bressan, A.; Chiosso, M.; Ciliberti, P.; Dalla Torre, S.; Denisov, O.; Duic, V.; Ferrero, A.; Finger, M.; Finger, M.; Gayde, J. Ch; Giorgi, M.; Gobbo, B.; Levorato, S.; Maggiora, A.; Martin, A.; Menon, G.; Panzieri, D.; Pesaro, G.; Polak, J.; Rocco, E.; Sbrizzai, G.; Schiavon, P.; Slunecka, M.; Sozzi, F.; Steiger, L.; Sulc, M.; Takekawa, S.; Tessarotto, F.
2014-01-01
The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM)
Determination of toxicity limiting values of Zn, Cu, and Pb for oat and red clover
Energy Technology Data Exchange (ETDEWEB)
Hodenberg, A V; Finck, A
1975-01-01
Toxicity limiting values of Zn, Cu and Pb are determined in order to investigate the causes of growth damages in certain fields. Since the true toxicity limit is difficult to estimate, a somewhat higher content is called the toxicity limiting value resulting after the subtraction of a significant yield difference. The pot experiments with increasing fertilization of Zn, Cu and Pb in soil cultures gave the following results. For Zn, the toxicity limit is 410 ppm in oats at the beginning of tilling. In red clover six weeks of age, it is only 290 ppm of Zn and therefore much lower. For Cu, the toxicity limit is 20 ppm in oats at the beginning of tilling and 18 ppm in six weeks old red clover. For Pb, a toxic effect could be observed above 50 ppm, but this does not seem to be the true limit because of disturbing salt effects.
Sexual polyploidization in red clover Poliploidização sexual em trevo vermelho
Directory of Open Access Journals (Sweden)
Carine Simioni
2006-02-01
Full Text Available Because sexual polyploidization broadens genetic basis and supply plant breeders with more variability for the selection process, it can be useful in red clover breeding. This paper reports results of three crossing cycles, starting from a parental generation of tetraploid red clover plants (female parent, and diploids from the Quiñiqueli cultivar, selected for production of more than 1% of giant pollen grains (male parent aiming to obtain tetraploid plants to be used in red clover breeding programs. Crosses in the next generations were performed by mutual cross-pollinations. Chromosome number chimerism and high pollen sterility were detected in F1, F2 and F3, but there was a trend towards increasing seed production and seed viability along the generations, probably due to successful competition between fertile and sterile gametes. The identification of fertile triploids, as well as their recurrent formation along the generations, indicates that triploid block is not complete in red clover, and that triploids may be successfully used as a bridge for the production of sexual polyploids.Porque a poliploidização sexual amplia a base genética e proporciona aos melhoristas maior variabilidade para o processo de seleção, ela pode ser uma ferramenta útil ao melhoramento de trevo vermelho. Com o objetivo de obter plantas tetraplóides que possam ser utilizadas em programas de melhoramento de trevo vermelho, este trabalho relata resultados de três ciclos de cruzamentos, partindo de uma população parental de plantas tetraplóides de trevo vermelho, como genitores femininos, e de diplóides da cultivar Quiñiqueli, selecionados para produção de mais de 1% de grãos de pólen gigantes, como genitores masculinos. Nas outras gerações, os cruzamentos foram realizados por polinizações cruzadas mútuas. Quimerismo para número cromossômico e alta esterilidade de pólen foram detectados em F1 , F2 e F3, mas houve uma tendência para aumento da
Parallel segmented outlet flow high performance liquid chromatography with multiplexed detection
International Nuclear Information System (INIS)
Camenzuli, Michelle; Terry, Jessica M.; Shalliker, R. Andrew; Conlan, Xavier A.; Barnett, Neil W.; Francis, Paul S.
2013-01-01
Graphical abstract: -- Highlights: •Multiplexed detection for liquid chromatography. •‘Parallel segmented outlet flow’ distributes inner and outer portions of the analyte zone. •Three detectors were used simultaneously for the determination of opiate alkaloids. -- Abstract: We describe a new approach to multiplex detection for HPLC, exploiting parallel segmented outlet flow – a new column technology that provides pressure-regulated control of eluate flow through multiple outlet channels, which minimises the additional dead volume associated with conventional post-column flow splitting. Using three detectors: one UV-absorbance and two chemiluminescence systems (tris(2,2′-bipyridine)ruthenium(III) and permanganate), we examine the relative responses for six opium poppy (Papaver somniferum) alkaloids under conventional and multiplexed conditions, where approximately 30% of the eluate was distributed to each detector and the remaining solution directed to a collection vessel. The parallel segmented outlet flow mode of operation offers advantages in terms of solvent consumption, waste generation, total analysis time and solute band volume when applying multiple detectors to HPLC, but the manner in which each detection system is influenced by changes in solute concentration and solution flow rates must be carefully considered
Parallel segmented outlet flow high performance liquid chromatography with multiplexed detection
Energy Technology Data Exchange (ETDEWEB)
Camenzuli, Michelle [Australian Centre for Research on Separation Science (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), Sydney, NSW (Australia); Terry, Jessica M. [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia); Shalliker, R. Andrew, E-mail: r.shalliker@uws.edu.au [Australian Centre for Research on Separation Science (ACROSS), School of Science and Health, University of Western Sydney (Parramatta), Sydney, NSW (Australia); Conlan, Xavier A.; Barnett, Neil W. [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia); Francis, Paul S., E-mail: paul.francis@deakin.edu.au [Centre for Chemistry and Biotechnology, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216 (Australia)
2013-11-25
Graphical abstract: -- Highlights: •Multiplexed detection for liquid chromatography. •‘Parallel segmented outlet flow’ distributes inner and outer portions of the analyte zone. •Three detectors were used simultaneously for the determination of opiate alkaloids. -- Abstract: We describe a new approach to multiplex detection for HPLC, exploiting parallel segmented outlet flow – a new column technology that provides pressure-regulated control of eluate flow through multiple outlet channels, which minimises the additional dead volume associated with conventional post-column flow splitting. Using three detectors: one UV-absorbance and two chemiluminescence systems (tris(2,2′-bipyridine)ruthenium(III) and permanganate), we examine the relative responses for six opium poppy (Papaver somniferum) alkaloids under conventional and multiplexed conditions, where approximately 30% of the eluate was distributed to each detector and the remaining solution directed to a collection vessel. The parallel segmented outlet flow mode of operation offers advantages in terms of solvent consumption, waste generation, total analysis time and solute band volume when applying multiple detectors to HPLC, but the manner in which each detection system is influenced by changes in solute concentration and solution flow rates must be carefully considered.
Kolodziejczyk-Czepas, Joanna; Nowak, Pawel; Kowalska, Iwona; Stochmal, Anna
2014-10-01
Clovers were chosen on the basis of traditional medicine recommendations, agricultural value, or available information on their promising chemical profiles. This study evaluates and compares free radical scavenging and antioxidant properties of six clover species: Trifolium alexandrinum L. (Leguminosae), Trifolium fragiferum L., Trifolium hybridum L., Trifolium incarnatum L., Trifolium resupinatum var. majus Boiss., and Trifolium resupinatum var. resupinatum L. Free radical scavenging activity of the extracts (1.5-50 µg/ml) was estimated by reduction of 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic) acid (ABTS(•)) radicals. The Trifolium extract effects on total antioxidant capacity of blood plasma were determined by the reduction of ABTS(•+) and DPPH(•) radicals, as well as with the use of the ferric reducing ability of plasma (FRAP) assay. The UPLC analysis of chemical profiles of the examined extracts showed the presence of three or four groups of phenolic substances, including phenolic acids, clovamides, isoflavones, and other flavonoids. The measurements of free radical scavenging and ferric reducing ability of the examined clover extracts revealed the strongest effect for T. alexandrinum. Furthermore, antioxidant activity assays in human plasma have shown protective effects of all extracts against peroxynitrite-induced reduction of total antioxidant capacity. Trifolium plants may be a rich source of bioactive substances with antioxidant properties. The examined extracts displayed free radical scavenging action and partly protected blood plasma against peroxynitrite-induced oxidative stress; however, the beneficial effects of T. alexandrinum and T. incarnatum seem to be slightly higher.
Directory of Open Access Journals (Sweden)
Marina Vranić
2009-06-01
Full Text Available The objective of this study was to determine effect of additive supplementation to red clover silage on ad libitum intake of fresh silage and dry matter (DM, in vivo digestibility of DM, organic matter (OM, OM in DM (D-value, crude protein (CP and nitrogen (N balance. Red clover was harvested at 60% bloom stage. It was ensiled into round bales without an additive (CD and with an additive supplementation (CDA in the amount of 2 L t-1 fresh material. Statistically lower (P<0.001 DM content was recorded in CD (405 g kg-1 fresh sample in comparison with CDA (665 g ST kg-1 fresh sample. Statistically higher CP content (P<0.001 was recorded in CD (127 g kg-1 ST in comparison with CDA (110 g SP kg-1 ST. CD had lower pH (P<0.001 (4.9 in comparison with CDA (5.2. No differences were recorded in NH3 between treatments. Ad libitum intake of fresh silage and silage DM was higher (P<0.001 and P<0.01, respectively in CD in comparison with CDA. Digestibility of DM, OM, CP, D-value and N balance were not different between treatments. It was concluded that the positive effect of additive supplementation to red clover silage on chemical composition, ad libitum intake, digestibility and N balance was not recorded due to applied ensiling technology as additive can improve feeding value of roughage, but it is not a replacement for good management practices.
Segmented slant hole collimator for stationary cardiac SPECT: Monte Carlo simulations.
Mao, Yanfei; Yu, Zhicong; Zeng, Gengsheng L
2015-09-01
This work is a preliminary study of a stationary cardiac SPECT system. The goal of this research is to propose a stationary cardiac SPECT system using segmented slant-hole collimators and to perform computer simulations to test the feasibility. Compared to the rotational SPECT, a stationary system has a benefit of acquiring temporally consistent projections. The most challenging issue in building a stationary system is to provide sufficient projection view-angles. A GATE (GEANT4 application for tomographic emission) Monte Carlo model was developed to simulate a two-detector stationary cardiac SPECT that uses segmented slant-hole collimators. Each detector contains seven segmented slant-hole sections that slant to a common volume at the rotation center. Consequently, 14 view-angles over 180° were acquired without any gantry rotation. The NCAT phantom was used for data generation and a tailored maximum-likelihood expectation-maximization algorithm was used for image reconstruction. Effects of limited number of view-angles and data truncation were carefully evaluated in the paper. Simulation results indicated that the proposed segmented slant-hole stationary cardiac SPECT system is able to acquire sufficient data for cardiac imaging without a loss of image quality, even when the uptakes in the liver and kidneys are high. Seven views are acquired simultaneously at each detector, leading to 5-fold sensitivity gain over the conventional dual-head system at the same total acquisition time, which in turn increases the signal-to-noise ratio by 19%. The segmented slant-hole SPECT system also showed a good performance in lesion detection. In our prototype system, a short hole-length was used to reduce the dead zone between neighboring collimator segments. The measured sensitivity gain is about 17-fold over the conventional dual-head system. The gate Monte Carlo simulations confirm the feasibility of the proposed stationary cardiac SPECT system with segmented slant
Segmented slant hole collimator for stationary cardiac SPECT: Monte Carlo simulations
Energy Technology Data Exchange (ETDEWEB)
Mao, Yanfei, E-mail: ymao@ucair.med.utah.edu [Department of Radiology, Utah Center for Advanced Imaging Research (UCAIR), University of Utah, Salt Lake City, Utah 84108 and Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112 (United States); Yu, Zhicong [Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States); Zeng, Gengsheng L. [Department of Radiology, Utah Center for Advanced Imaging Research (UCAIR), University of Utah, Salt Lake City, Utah 84108 and Department of Engineering, Weber State University, Ogden, Utah 84408 (United States)
2015-09-15
Purpose: This work is a preliminary study of a stationary cardiac SPECT system. The goal of this research is to propose a stationary cardiac SPECT system using segmented slant-hole collimators and to perform computer simulations to test the feasibility. Compared to the rotational SPECT, a stationary system has a benefit of acquiring temporally consistent projections. The most challenging issue in building a stationary system is to provide sufficient projection view-angles. Methods: A GATE (GEANT4 application for tomographic emission) Monte Carlo model was developed to simulate a two-detector stationary cardiac SPECT that uses segmented slant-hole collimators. Each detector contains seven segmented slant-hole sections that slant to a common volume at the rotation center. Consequently, 14 view-angles over 180° were acquired without any gantry rotation. The NCAT phantom was used for data generation and a tailored maximum-likelihood expectation-maximization algorithm was used for image reconstruction. Effects of limited number of view-angles and data truncation were carefully evaluated in the paper. Results: Simulation results indicated that the proposed segmented slant-hole stationary cardiac SPECT system is able to acquire sufficient data for cardiac imaging without a loss of image quality, even when the uptakes in the liver and kidneys are high. Seven views are acquired simultaneously at each detector, leading to 5-fold sensitivity gain over the conventional dual-head system at the same total acquisition time, which in turn increases the signal-to-noise ratio by 19%. The segmented slant-hole SPECT system also showed a good performance in lesion detection. In our prototype system, a short hole-length was used to reduce the dead zone between neighboring collimator segments. The measured sensitivity gain is about 17-fold over the conventional dual-head system. Conclusions: The GATE Monte Carlo simulations confirm the feasibility of the proposed stationary cardiac
Baby MIND: a magnetized segmented neutrino detector for the WAGASCI experiment
Antonova, M.; Asfandiyarov, R.; Bayes, R.; Benoit, P.; Blondel, A.; Bogomilov, M.; Bross, A.; Cadoux, F.; Cervera, A.; Chikuma, N.; Dudarev, A.; Ekelöf, T.; Favre, Y.; Fedotov, S.; Hallsjö, S.-P.; Izmaylov, A.; Karadzhov, Y.; Khabibullin, M.; Khotyantsev, A.; Kleymenova, A.; Koga, T.; Kostin, A.; Kudenko, Y.; Likhacheva, V.; Martinez, B.; Matev, R.; Medvedeva, M.; Mefodiev, A.; Minamino, A.; Mineev, O.; Nessi, M.; Nicola, L.; Noah, E.; Ovsiannikova, T.; Pais Da Silva, H.; Parsa, S.; Rayner, M.; Rolando, G.; Shaykhiev, A.; Simion, P.; Soler, F. J. P.; Suvorov, S.; Tsenov, R.; Ten Kate, H.; Vankova-Kirilova, G.; Yershov, N.
2017-07-01
T2K (Tokai-to-Kamioka) is a long-baseline neutrino experiment in Japan designed to study various parameters of neutrino oscillations. A near detector complex (ND280) is located 280 m downstream of the production target and measures neutrino beam parameters before any oscillations occur. ND280's measurements are used to predict the number and spectra of neutrinos in the Super-Kamiokande detector at the distance of 295 km. The difference in the target material between the far (water) and near (scintillator, hydrocarbon) detectors leads to the main non-cancelling systematic uncertainty for the oscillation analysis. In order to reduce this uncertainty a new WAter-Grid-And-SCintillator detector (WAGASCI) has been developed. A magnetized iron neutrino detector (Baby MIND) will be used to measure momentum and charge identification of the outgoing muons from charged current interactions. The Baby MIND modules are composed of magnetized iron plates and long plastic scintillator bars read out at the both ends with wavelength shifting fibers and silicon photomultipliers. The front-end electronics board has been developed to perform the readout and digitization of the signals from the scintillator bars. Detector elements were tested with cosmic rays and in the PS beam at CERN. The obtained results are presented in this paper.
Baby MIND: a magnetized segmented neutrino detector for the WAGASCI experiment
International Nuclear Information System (INIS)
Antonova, M.; Fedotov, S.; Izmaylov, A.; Khabibullin, M.; Khotyantsev, A.; Kleymenova, A.; Asfandiyarov, R.; Blondel, A.; Cadoux, F.; Favre, Y.; Karadzhov, Y.; Bayes, R.; Hallsjö, S-P.; Benoit, P.; Dudarev, A.; Bogomilov, M.; Bross, A.; Cervera, A.; Chikuma, N.; Ekelöf, T.
2017-01-01
T2K (Tokai-to-Kamioka) is a long-baseline neutrino experiment in Japan designed to study various parameters of neutrino oscillations. A near detector complex (ND280) is located 280 m downstream of the production target and measures neutrino beam parameters before any oscillations occur. ND280's measurements are used to predict the number and spectra of neutrinos in the Super-Kamiokande detector at the distance of 295 km. The difference in the target material between the far (water) and near (scintillator, hydrocarbon) detectors leads to the main non-cancelling systematic uncertainty for the oscillation analysis. In order to reduce this uncertainty a new WAter-Grid-And-SCintillator detector (WAGASCI) has been developed. A magnetized iron neutrino detector (Baby MIND) will be used to measure momentum and charge identification of the outgoing muons from charged current interactions. The Baby MIND modules are composed of magnetized iron plates and long plastic scintillator bars read out at the both ends with wavelength shifting fibers and silicon photomultipliers. The front-end electronics board has been developed to perform the readout and digitization of the signals from the scintillator bars. Detector elements were tested with cosmic rays and in the PS beam at CERN. The obtained results are presented in this paper.
Baby MIND: A Magnetized Segmented Neutrino Detector for the WAGASCI Experiment
Energy Technology Data Exchange (ETDEWEB)
Antonova, M.; et al.
2017-07-19
T2K (Tokai-to-Kamioka) is a long-baseline neutrino experiment in Japan designed to study various parameters of neutrino oscillations. A near detector complex (ND280) is located 280 m downstream of the production target and measures neutrino beam parameters before any oscillations occur. ND280's measurements are used to predict the number and spectra of neutrinos in the Super-Kamiokande detector at the distance of 295 km. The difference in the target material between the far (water) and near (scintillator, hydrocarbon) detectors leads to the main non-cancelling systematic uncertainty for the oscillation analysis. In order to reduce this uncertainty a new WAter-Grid-And-SCintillator detector (WAGASCI) has been developed. A magnetized iron neutrino detector (Baby MIND) will be used to measure momentum and charge identification of the outgoing muons from charged current interactions. The Baby MIND modules are composed of magnetized iron plates and long plastic scintillator bars read out at the both ends with wavelength shifting fibers and silicon photomultipliers. The front-end electronics board has been developed to perform the readout and digitization of the signals from the scintillator bars. Detector elements were tested with cosmic rays and in the PS beam at CERN. The obtained results are presented in this paper.
Directory of Open Access Journals (Sweden)
Lin, XG.
1993-01-01
Full Text Available Investigation on the effect of phosphorus on vesicular-arbuscular mycorrhizal infection, and dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover under field microplots and pot experiments was conducted on fluvo-aquic soils of semi-arid region in north China. The results showed that 60 kg P205 ha in form of superphosphate was the most favorable phosphorus level for vesicular-arbuscular mycorrhizal infection ; mycorrhizal infection, nodulation, dry weight of shoots and roots, total uptake of nitrogen, phosphorus and other elements, the final yields and recovery of phosphorus of white clover were significantly increased by vesicular-arbuscular mycorrhizal inoculation and dual inoculation with vesicular-arbuscular mycorrhizal fungi and rhizobium. The highest response of inoculation was obtained by adding fertilizer phosphorus at the level of 60 kg P205 ha in form of superphosphate.
Feasibility study of segmented-parallel-hole collimator for stationary cardiac SPECT
Energy Technology Data Exchange (ETDEWEB)
Mao, Yanfei [Utah Univ., Salt Lake City, UT (United States). Center for Advanced Imaging Research (UCAIR); Utah Univ., Salt Lake City, UT (United States). Dept. of Bioengineering; Zeng, Gengsheng L. [Utah Univ., Salt Lake City, UT (United States). Center for Advanced Imaging Research (UCAIR)
2011-07-01
The goal of this research is to propose a stationary cardiac SPECT system using the segmented parallel-beam collimator and to perform some computer simulations to test the feasibility. A stationary system has a benefit of acquiring temporally consistent projections. The most challenging issue in building a stationary system is to provide sufficient projection view-angles. A 2-detector, multi-segment collimator system with 14 view-angles over 180 in the transaxial direction and 3 view-angles in the axial directions was designed, where the two detectors are configured 90 apart in an L-shape. We applied the parallel-beam imaging geometry and used segmented parallel-hole collimator to acquire SPECT data. To improve the system condition due to data truncation, we measured more rays within the field-of-view (FOV) of the detector by using a relatively small detector bin-size. In image reconstruction, we used the maximum-likelihood expectation-maximization (ML-EM) algorithm. The criterion for evaluating the system is the summed pixel-to-pixel distance that measures the discrepancy between the 3D gold-standard image and the reconstructed 3D region of interest (ROI) with truncated data. Effects of limited number of view-angles, data truncation, varying body habitus, attenuation, and noise were considered in the system design. As a result, our segmented-parallel-beam stationary cardiac SPECT system is able to acquire sufficient data for cardiac imaging and has a high sensitivity gain. (orig.)
International Nuclear Information System (INIS)
Wang Yi; Antonuk, Larry E.; El-Mohri, Youcef; Zhao Qihua
2009-01-01
Thick, segmented scintillating detectors, consisting of 2D matrices of scintillator crystals separated by optically opaque septal walls, hold considerable potential for significantly improving the performance of megavoltage (MV) active matrix, flat-panel imagers (AMFPIs). Initial simulation studies of the radiation transport properties of segmented detectors have indicated the possibility of significant improvement in DQE compared to conventional MV AMFPIs based on phosphor screen detectors. It is therefore interesting to investigate how the generation and transport of secondary optical photons affect the DQE performance of such segmented detectors. One effect that can degrade DQE performance is optical Swank noise (quantified by the optical Swank factor I opt ), which is induced by depth-dependent variations in optical gain. In this study, Monte Carlo simulations of radiation and optical transport have been used to examine I opt and zero-frequency DQE for segmented CsI:Tl and BGO detectors at different thicknesses and element-to-element pitches. For these detectors, I opt and DQE were studied as a function of various optical parameters, including absorption and scattering in the scintillator, absorption at the top reflector and septal walls, as well as scattering at the side surfaces of the scintillator crystals. The results indicate that I opt and DQE are only weakly affected by absorption and scattering in the scintillator, as well as by absorption at the top reflector. However, in some cases, these metrics were found to be significantly degraded by absorption at the septal walls and scattering at the scintillator side surfaces. Moreover, such degradations are more significant for detectors with greater thickness or smaller element pitch. At 1.016 mm pitch and with optimized optical properties, 40 mm thick segmented CsI:Tl and BGO detectors are predicted to provide DQE values of ∼29% and 42%, corresponding to improvement by factors of ∼29 and 42
Neutron detector development at Brookhaven
International Nuclear Information System (INIS)
Yu, B.; Harder, J.A.; Mead, J.A.; Radeka, V.; Schaknowski, N.A.; Smith, G.C.
2003-01-01
Two-dimensional thermal neutron detectors have been the subject of research and development at Brookhaven for over 20 years. Based primarily on multi-wire chambers filled with a gas mixture containing 3 He, these detectors have been used in wide-ranging studies of molecular biology and material science samples. At each phase of development, experimenters have sought improvements in key parameters such as position resolution, counting rate, efficiency, solid-angle coverage and stability. A suite of detectors has been developed with sensitive areas ranging from 5x5 to 50x50 cm 2 . These devices incorporate low-noise-position readout and the best position resolution for thermal neutron gas detectors. Recent developments include a 1.5 mx20 cm detector containing multiple segments with continuously sensitive readout, and detectors with unity gain for ultra-high rate capability and long-term stability
Hazotte, Alice; Péron, Olivier; Gaudin, Pierre; Abdelouas, Abdesselam; Lebeau, Thierry
2018-05-12
With the aim of improving the phytoextraction rate of cesium (Cs), the effect of Pseudomonas fluorescens ATCC 17400 and its siderophore pyoverdine (PVD) on the uptake of Cs by red clover was studied in soil pots. This work also provides a mechanistic understanding of the Cs-bacteria (or PVD)-illite-plant interactions by using a simplified experimental design, i.e., hydroponics with either Cs in solution or Cs-spiked illite in suspension. For soil spiked with 11.2 mmol kg -1 (1480 mg kg -1 ) of Cs, 0.43% of total Cs was taken up by red clover in 12 days (119 μmol g -1 (16 mg g -1 ) of Cs dry matter in roots and 40 μmol g -1 (5 mg g -1 ) in shoots). In hydroponics with Cs in solution (0.1 mmol L -1 or 13 mg L -1 ), 75% of Cs was taken up vs. only 0.86% with Cs-spiked illite suspension. P. fluorescens and PVD did not increase Cs concentrations in aboveground parts and roots of red clover and even decreased them. The damaging effect of PVD on red clover growth was demonstrated with the biomass yielding 66% of the control in soil pots (and 100% mortality after 12 days of exposition) and only 56% in hydroponics (78% with illite in suspension). Nonetheless, PVD and, to a lesser extent, P. fluorescens increased the translocation factor up to a factor of 2.8. This study clearly showed a direct damaging effect of PVD and to a lower extent the retention of Cs by biofilm covering both the roots and illite, both resulting in the lower phytoextraction efficiency.
Directory of Open Access Journals (Sweden)
Khosro Mehdi Khanlou
2011-01-01
Full Text Available Cost reduction in plant breeding and conservation programs depends largely on correctly defining the minimal sample size required for the trustworthy assessment of intra- and inter-cultivar genetic variation. White clover, an important pasture legume, was chosen for studying this aspect. In clonal plants, such as the aforementioned, an appropriate sampling scheme eliminates the redundant analysis of identical genotypes. The aim was to define an optimal sampling strategy, i.e., the minimum sample size and appropriate sampling scheme for white clover cultivars, by using AFLP data (283 loci from three popular types. A grid-based sampling scheme, with an interplant distance of at least 40 cm, was sufficient to avoid any excess in replicates. Simulations revealed that the number of samples substantially influenced genetic diversity parameters. When using less than 15 per cultivar, the expected heterozygosity (He and Shannon diversity index (I were greatly underestimated, whereas with 20, more than 95% of total intra-cultivar genetic variation was covered. Based on AMOVA, a 20-cultivar sample was apparently sufficient to accurately quantify individual genetic structuring. The recommended sampling strategy facilitates the efficient characterization of diversity in white clover, for both conservation and exploitation.
Nucleon form factors and structure functions from Nf=2 Clover fermions
International Nuclear Information System (INIS)
Collins, S.; Goeckeler, M.; Haegler, P.
2010-12-01
We give an update on our ongoing efforts to compute the nucleon's form factors and moments of structure functions using N f =2 flavours of non-perturbatively improved Clover fermions. We focus on new results obtained on gauge configurations where the pseudo-scalar meson mass is in the range of 170-270 MeV. We compare our results with various estimates obtained from chiral effective theories since we have some overlap with the quark mass region where results from such theories are believed to be applicable. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Dong Yan; Zhu Yongguan [Department of Soil Environmental Science, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Smith, F. Andrew [Soil and Land Systems, School of Earth and Environmental Sciences, Waite Campus, University of Adelaide, Adelaide, SA 5005 (Australia); Wang Youshan [Institute of Plant Nutrition and Resources, Beijing Academy of Agriculture and Forestry, Beijing 100089 (China); Chen Baodong [Department of Soil Environmental Science, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)], E-mail: bdchen@rcees.ac.cn
2008-09-15
In a compartmented cultivation system, white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.), with their roots freely intermingled, or separated by 37 {mu}m nylon mesh or plastic board, were grown together in an arsenic (As) contaminated soil. The influence of AM inoculation on plant growth, As uptake, phosphorus (P) nutrition, and plant competitions were investigated. Results showed that both plant species highly depended on mycorrhizas for surviving the As contamination. Mycorrhizal inoculation substantially improved plant P nutrition, and in contrast markedly decreased root to shoot As translocation and shoot As concentrations. It also showed that mycorrhizas affected the competition between the two co-existing plant species, preferentially benefiting the clover plants in term of nutrient acquisition and biomass production. Based on the present study, the role of AM fungi in plant adaptation to As contamination, and their potential use for ecological restoration of As contaminated soils are discussed. - Both white clover and ryegrass highly depend on the mycorrhizal associations for surviving heavy arsenic contamination.
International Nuclear Information System (INIS)
Dong Yan; Zhu Yongguan; Smith, F. Andrew; Wang Youshan; Chen Baodong
2008-01-01
In a compartmented cultivation system, white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.), with their roots freely intermingled, or separated by 37 μm nylon mesh or plastic board, were grown together in an arsenic (As) contaminated soil. The influence of AM inoculation on plant growth, As uptake, phosphorus (P) nutrition, and plant competitions were investigated. Results showed that both plant species highly depended on mycorrhizas for surviving the As contamination. Mycorrhizal inoculation substantially improved plant P nutrition, and in contrast markedly decreased root to shoot As translocation and shoot As concentrations. It also showed that mycorrhizas affected the competition between the two co-existing plant species, preferentially benefiting the clover plants in term of nutrient acquisition and biomass production. Based on the present study, the role of AM fungi in plant adaptation to As contamination, and their potential use for ecological restoration of As contaminated soils are discussed. - Both white clover and ryegrass highly depend on the mycorrhizal associations for surviving heavy arsenic contamination
DEFF Research Database (Denmark)
Parajuli, Ranjan; Kristensen, Ib Sillebak; Knudsen, Marie Trydeman
2017-01-01
The aim of this study is to assess the potential environmental impacts of producing maize, grass-clover, ryegrass, and straw from winter wheat as biomass feedstocks for biorefinery. The Life Cycle Assessment (LCA) method included the following impact categories: Global Warming Potential (GWP100),...
Directory of Open Access Journals (Sweden)
JUAN C CARRILLO
2004-01-01
Full Text Available A series of experiments were carried out in order to optimize a protocol for the direct organogenesis of Chilean red clover germplasm. A range of cultivars were used to analyze the effect of explant source (crown or stem meristems of vegetative plants, culture media and plant growth regulators. Our findings showed that stem meristems were easier to obtain, presented lower levels of contamination and a better development than crown meristems. The L2 medium showed better results than B5 and MS media for the cultivars and experimental lines studied. L2 medium supplemented with 0.003 mg/l of 4-amino-3,5,6-trichloropicolinic acid and 1.0 mg/l of 6-benzylaminopurine gave consistently better results and will be applied in our breeding program to propagate, maintain and eliminate viruses from elite red clover clones.
Cleaning the Soil from Zinc Using Red Clovers “Arimaičiai”
Audronė Mikalajūnė; Giedrė Jasulaitytė
2011-01-01
Zinc as a nutrition element is required to plants in small quantities to maintain normal functions of metabolism mechanisms. Our work analyses the efficiency of red clovers “Arimaičiai” for cleaning zinc from the soil contaminated with zinc under laboratory conditions. Seeds were sown in three differently polluted soils: clean soil, once contaminated with zinc and periodically contaminated with zinc soil. Zinc concentration in one time contaminated soil was 45 mg/kg. After 6 months of phytore...
DEFF Research Database (Denmark)
Carter, Mette Sustmann; Ambus, P.
2006-01-01
The contribution of biologically fixed dinitrogen (N-2) to the nitrous oxide (N2O) production in grasslands is unknown. To assess the contribution of recently fixed N-2 as a source of N2O and the transfer of fixed N from clover to companion grass, mixtures of white clover and perennial ryegrass...
A novel line segment detection algorithm based on graph search
Zhao, Hong-dan; Liu, Guo-ying; Song, Xu
2018-02-01
To overcome the problem of extracting line segment from an image, a method of line segment detection was proposed based on the graph search algorithm. After obtaining the edge detection result of the image, the candidate straight line segments are obtained in four directions. For the candidate straight line segments, their adjacency relationships are depicted by a graph model, based on which the depth-first search algorithm is employed to determine how many adjacent line segments need to be merged. Finally we use the least squares method to fit the detected straight lines. The comparative experimental results verify that the proposed algorithm has achieved better results than the line segment detector (LSD).
Blum, Oleg; Didyk, Nataliya; Pavluchenko, Nataliya; Godzik, Barbara
2011-01-01
Some modern agrochemicals with antioxidant potential were tested for their protective effect against ozone injury using clover and tobacco ozone-sensitive cultivars as model plants subjected to ambient ozone at two sites (Kyiv city in Ukraine and Szarów village in Poland). All used agrochemicals showed partial protective effects against ozone injury on clover and tobacco. Conducted studies confirmed the effectiveness of modern fungicides belonging to strobilurin group as protectants of sensitive crops against ozone damage. The effectiveness of new growth regulators "Emistym C" and "Agrostymulin" was showed for the first time. Out of the studied agrochemicals, fungicide "Strobi" and natural growth regulator "Emistym C" demonstrated the best protective effects. These agrochemicals present promise for further studies of their possible utilization for enhancement of ozone tolerance of sensitive crops.
International Nuclear Information System (INIS)
Osztoics, E.; Bujtas, K.
1999-01-01
The impacts of superphosphate and Algerian phosphate rock and their various application rates on soil pH and on the availability of trace elements by red clover were studied in a pot experiment on several types of acidic soils from the Carpathian basin. The differences among the soils' original pH and texture, and those differences in soil pH, which resulted from the application of different P forms and rotes were reflected in the Mn, Ni, Al, Co, Sr, Cd and Cr contents of red clover. Plant concentrations of those elements were smaller on the slightly acidic than on the strongly and extremely strongly acidic soils. Elemental concentrations were generally higher when there was less time between two cuts, and decreased in the later cuts. Refs. 11 (author)
This experiment was conducted in 2005-2007 to evaluate carcass and meat quality parameters when meat goat kids were finished on alfalfa (Medicago sativa L; ALF); red clover (Trifolium pretense L.; RCG); or orchardgrass (Dactylis glomerata L; OGR) pastures. Final shrunk body weights were similar whe...
Annibale, D' Alessandra; Sechi, Valentina; Larsen, Thomas; Christensen, Søren; Krogh, Paul Henning; Eriksen, Jørgen
2017-01-01
Introduction of legumes (i.e. white clover) in agricultural grasslands is a common practice to improve yields, but how this affects soil fauna populations, particularly mesofauna, is still poorly understood. We investigated taxonomical and functional differences of Collembola communities between
Jin, Zhong Min; Sha, Wei; Zhang, Yan Fu; Zhao, Jing; Ji, Hongyang
2013-07-01
Phytoremediation combined with suitable microorganisms and biodegradable chelating agents can be a means of reclaiming lands contaminated by toxic heavy metals. We investigated the ability of a lead- and cadmium-resistant bacterial strain (JB12) and the biodegradable chelator ethylenediamine-N,N'-disuccinic acid (EDDS) to improve absorption of these metals from soil by tall fescue and red clover. Strain JB12 was isolated from contaminated soil samples, analysed for lead and cadmium resistance, and identified as Burkholderia cepacia. Tall fescue and red clover were grown in pots to which we added JB12, (S,S)-EDDS, combined JB12 and EDDS, or water only. Compared with untreated plants, the biomass of plants treated with JB12 was significantly increased. Concentrations of lead and cadmium in JB12-treated plants increased significantly, with few exceptions. Plants treated with EDDS responded variably, but in those treated with combined EDDS and JB12, heavy metal concentrations increased significantly in tall fescue and in the aboveground parts of red clover. We conclude that JB12 is resistant to lead and cadmium. Its application to the soil improved the net uptake of these heavy metals by experimental plants. The potential for viable phytoremediation of lead- and cadmium-polluted soils with tall fescue and red clover combined with JB12 was further enhanced by the addition of EDDS.
The EUROBALL neutron wall - design and performance tests of neutron detectors
Skeppstedt, Ö; Lindström, L; Wadsworth, R; Hibbert, I; Kelsall, N; Jenkins, D; Grawe, H; aGórska, M; Moszynski, M; Sujkowski, Z; Wolski, D; Kapusta, M; Hellström, M; Kalogeropoulos, S; Oner, D; Johnson, A; Cederkäll, J; Klamra, W; Nyberg, J; Weiszflog, M; Kay, J; Griffiths, R; Garces-Narro, J; Pearson, C; Eberth, J
1999-01-01
The mechanical design of the EUROBALL neutron wall and neutron detectors, and their performance measured with a sup 2 sup 4 sup 6 sup , sup 2 sup 4 sup 8 Cm fission source are described. The array consists of 15 pseudohexaconical detector units subdivided into three, 149 mm high, hermetically separated segments and a smaller central pentagonal unit subdivided into five segments. The detectors are filled with Bicron BC501A liquid scintillator. Each section of the hexaconical detectors is viewed by a 130 mm diameter Philips XP4512PA photomultiplier while the sections of pentagonal detectors are viewed by Philips XP4312B PMTs. The tests of n-gamma discrimination performed by zero-crossing and time-of-flight methods show a full separation of gamma- and neutron events down to 50 keV recoil electron energy. These tests demonstrate the excellent timing properties of the detectors and an average time resolution of 1.56 ns. The factors determining the efficiency of neutron detectors are discussed. The total efficiency...
Detector Development for the abBA Experiment.
Seo, P-N; Bowman, J D; Mitchell, G S; Penttila, S I; Wilburn, W S
2005-01-01
We have developed a new type of field-expansion spectrometer to measure the neutron beta decay correlations (a, b, B, and A). A precision measurement of these correlations places stringent requirements on charged particle detectors. The design employs large area segmented silicon detectors to detect both protons and electrons in coincidence. Other requirements include good energy resolution (electron-backscattering events, and nearly unity efficiency. We report results of testing commercially available surface-barrier silicon detectors for energy resolution and timing performance, and measurement of the dead-layer thickness of ion-implanted silicon detectors with a 3.2 MeV alpha source.
Directory of Open Access Journals (Sweden)
Tadeusz Zając
2013-12-01
Full Text Available Two red clover breeding strains with elongated flower heads, developed by one of the authors (H.Góral, were studied for forage and seed yield and compared to the standard cultivar 'Nike'. In addition, six morphological shoot traits were measured and their interrelations were computed. The leaf area index (LAI of successive cuts in two harvest years was determined on the basis of shoot density and leaf area of individual shoots. All three genotypes exhibited a high leaf area on shoots and a very high forage productivity. Among the morphological traits only shoot height could be a good selective criterion because it is easily measured, is significantly associated with shoot weight and shoot leaf area and its variation is low. Both strains, particularly the one with longer inflorescences belong to short-lived red clover forms giving satis factory forage and seed yields in the first harvest year. Depending on the strain the number of seeds per elongated inflorescence in the first harvest year was higher by 92 and 42% compared to that of a standard cultivar.
Hadron shower profile and direction measurements in a segmented calorimeter
International Nuclear Information System (INIS)
Auchincloss, P.; Blair, R.; Haber, C.
1982-01-01
Recently a test measurement was made to see how well the direction of the shower induced by neutrino interactions could be determined in the lab-E detector at Fermilab. While the calorimeter in lab-E has very coarse sampling compared to the detectors described at this workshop, the method used to sample the shower could be employed in other more finely segmented detectors. The shower angle resolution obtained (36 mr.FWHM) is largely constrained by the sampling. In this test pulse heights in 2mm. steps across the hadron shower at five points along the shower were recorded. This was done with 20 wires and 20 fast ADC's. A standard MWPC system intended to accomplish the same task would have required about 250 wires and 250 ADC channels. This considerable saving in system complexity should be possible for any system where finely segmented pulse height measurements are required
Automatic segmentation of mandible in panoramic x-ray
Abdi, Amir Hossein; Kasaei, Shohreh; Mehdizadeh, Mojdeh
2015-01-01
As the panoramic x-ray is the most common extraoral radiography in dentistry, segmentation of its anatomical structures facilitates diagnosis and registration of dental records. This study presents a fast and accurate method for automatic segmentation of mandible in panoramic x-rays. In the proposed four-step algorithm, a superior border is extracted through horizontal integral projections. A modified Canny edge detector accompanied by morphological operators extracts the inferior border of t...
DEFF Research Database (Denmark)
Schulze, A.K.S.; Nørgaard, P.; Byskov, M.V.
2015-01-01
The physical structure value of conserved grass/clover forages of spring harvest was evaluated by assessing effects of harvest time, conservation method, iNDF/NDF ratio and NDF intake (NDFI) per kg BW on chewing activity and fecal particle size in dairy heifers. A mixed sward consisting of ryegrass...
High voltage distribution scheme for large size GEM detector
International Nuclear Information System (INIS)
Saini, J.; Kumar, A.; Dubey, A.K.; Negi, V.S.; Chattopadhyay, S.
2016-01-01
Gas Electron Multiplier (GEM) detectors will be used for Muon tracking in the Compressed Baryonic Matter (CBM) experiment at the Facility for Anti-proton Ion Research (FAIR) at Darmstadt, Germany. The sizes of the detector modules in the Muon chambers are of the order of 1 metre x 0.5 metre. For construction of these chambers, three GEM foils are used per chamber. These foils are made by two layered 50μm thin kapton foil. Each GEM foil has millions of holes on it. In such a large scale manufacturing of the foils, even after stringent quality controls, some of the holes may still have defects or defects might develop over the time with operating conditions. These defects may result in short-circuit of the entire GEM foil. A short even in a single hole will make entire foil un-usable. To reduce such occurrences, high voltage (HV) segmentation within the foils has been introduced. These segments are powered either by individual HV supply per segment or through an active HV distribution to manage such a large number of segments across the foil. Individual supplies apart from being costly, are highly complex to implement. Additionally, CBM will have high intensity of particles bombarding on the detector causing the change of resistive chain current feeding the GEM detector with the variation in the intensity. This leads to voltage fluctuations across the foil resulting in the gain variation with the particle intensity. Hence, a low cost active HV distribution is designed to take care of the above discussed issues
DEFF Research Database (Denmark)
Jørgensen, F.V.; Jensen, E.S.; Schjørring, J.K.
1999-01-01
Dinitrogen fixation in white clover (Trifolium repens L.) grown in pure stand and mixture with perennial ryegrass (Lolium perenne L.) was determined in the field using N-15 isotope dilution and harvest of the shoots. The apparent transfer of clover N to perennial ryegrass was simultaneously...... assessed. The soil was labelled either by immobilizing N-15 in organic matter prior to establishment of the sward or by using the conventional labelling procedure in which N-15 fertilizer is added after sward establishment. Immobilization of N-15 in the soil organic matter has not previously been used...
DEFF Research Database (Denmark)
Johansen, Marianne; Hellwing, Anne Louise Frydendahl; Lund, Peter
2017-01-01
The aim of this experiment was to study the effect of increased dry matter (DM) concentration in grass-clover silage, obtained by extending the pre-wilting period before ensiling, on the amount of metabolisable protein (MP) supplied to lactating dairy cows. Spring growth and first regrowth of grass...... and faeces, respectively, were collected over 94 h to cover the diurnal variation, pooled, and subsequently analysed. Rumen fluid was collected in same sampling procedure. To estimate the duodenal flow of microbial protein, microbes were isolated from the rumen and analysed for amino acids (AA) and purines...... flow of AA. The higher duodenal flow of AA derived from a lower rumen degradation of feed protein and a tendency towards a higher microbial synthesis in the rumen. Fibre digestibility and CH4 production were not affected by silage DM concentration. In conclusion, MP concentration in grass-clover silage...
An improved segmented gamma scanning for radioactive waste drums
International Nuclear Information System (INIS)
Liu Cheng; Wang Dezhong; Bai Yunfei; Qian Nan
2010-01-01
In this paper, the equivalent radius of radioactive sources in each segment is determined by analyzing the different responses of the two identical detectors, and an improved segmented gamma scanning is used to assay waste drums containing mainly organic materials, and proved by an established simulation model. The simulated radioactivity distributions in homogenous waste drum and an experimental heterogeneous waste drum were compared with those of traditional segmented gamma scanning. The results show that our method is good in performance and can be used for analyzing the waste drums. (authors)
International Nuclear Information System (INIS)
Goetz, E; Riles, K
2016-01-01
We present a method for coherently combining short data segments from gravitational-wave detectors to improve the sensitivity of semi-coherent searches for continuous gravitational waves. All-sky searches for continuous gravitational waves from unknown sources are computationally limited. The semi-coherent approach reduces the computational cost by dividing the entire observation timespan into short segments to be analyzed coherently, then combined together incoherently. Semi-coherent analyses that attempt to improve sensitivity by coherently combining data from multiple detectors face a computational challenge in accounting for uncertainties in signal parameters. In this article, we lay out a technique to meet this challenge using summed Fourier transform coefficients. Applying this technique to one all-sky search algorithm called TwoSpect, we confirm that the sensitivity of all-sky, semi-coherent searches can be improved by coherently combining the short data segments, e.g., by up to 42% over a single detector for an all-sky search. For misaligned detectors, however, this improvement requires careful attention when marginalizing over unknown polarization parameters. In addition, care must be taken in correcting for differential detector velocity due to the Earth’s rotation for high signal frequencies and widely separated detectors. (paper)
Results from the crystal ball detector at SPEAR
International Nuclear Information System (INIS)
Bloom, E.D.
1979-11-01
The Crystal Ball detector is a device particularly suited to the measurement of photons with energies lower than 1 GeV. The detector has as its principal component a 16 radiation length thick, highly segmented shell of NaI(Tl) surrounding cylindrical, proportional, and magnetostrictive spark chambers. The main Ball and various elements of the central chambers cover 94% of 4π sr. Segmented endcap NaI(Tl) detectors of 20 radiation lengths behind magneto strictive spark chambers supplement the main Ball. The Ball and endcaps close the solid angle for charged particle and photon detection to 98% of 4π sr. In addition, detectors of interspersed iron and proportional tubes provide for μ-π separation over 15% of 4π sr, about theta/sub CM/ = 90 0 . In this report preliminary results are presented from the data obtained. In particular, QED at E/sub CM/ = 6.5 GeV, R/sub hadron/ and related inclusive distributions, eta branching fractions at J/psi and psi'', and a detailed study of the psionium system are discussed
Energy Technology Data Exchange (ETDEWEB)
Schwertel, Sabine
2009-11-26
highly segmented detectors with an efficiency {epsilon}>98 % could be built from this material. The diamond detectors were segmented in our laboratory and achieved a time resolution of {sigma}{sub t}=75 ps. Medium-size (25.4 x 25.4 mm{sup 2}) micro-strip detectors were tested at the FRS and at the ALADIN/LAND setup at GSI. The obtained position resolution was in the range of the strip size of 200 {mu}m. First full-size detectors (50 x 50 mm{sup 2}) will be completed soon. (orig.)
Directory of Open Access Journals (Sweden)
Hassan Shahgholi
2016-09-01
Full Text Available Introduction: Herbicides, despite of their control of weeds, have the potential to affect sensitive crops in rotation and also beneficial non-targeted soil microbes including vesicular arbuscular mycorrhiza (VAM fungi (6. AM fungi can increase the growth of crops through increasing uptake of phosphorus and insoluble micronutrients, and indirectly by improving soil quality parameters (30. However, several authors have reported different effects of herbicides on VAM symbiosis, which ranges from no adverse effects to slightly or highly toxic effects (6. Pesticides have also been reported to stimulate colonization of plant roots by AM fungi (27. Therefore, the objective of this study was to investigate the interaction effects of mycorrhizal fungi and Trifluralin herbicide on the growth and root colonization of clover. Materials and Methods: A factorial experiment was arranged in randomized complete block design with three replicates at the College of Agricultural, University of Shahrood during 2012. Treatments were included three levels of mycorrhiza inoculation, M1: non mycorrhiza (control, M2: Glommus mosseae and M3: Glommus intraradices and herbicide treatments were included four levels of Trifluralin(T1: 0, T2: 1000, T3: 1500 and T4: 2000 ml ha-1. In mycorrhizal treatments, 20 g inoculums were thoroughly mixed with soil. Seeds of clover (Trifolium repens L. were sown in the pots maintained near the field in order to provide normal environmental conditions. Seedlings were thinned to two plants per pot at three leaf stages. At the time of harvesting, the emergence and growth characteristics of clover and root colonization was also registered. Statistical analyses of data were performed with statistical software MSTATC. Significant differences between means refer to the probability level of 0.05 calculated by LSD test. Results and Discussion: The results showed that emergence, uniformity (EU values decreased and time to 10% (D10 and 90% (D90 of
International Nuclear Information System (INIS)
Kowalska, T. K.; Kwiatkowaska, E.
2016-01-01
A 4-year plot experiment was conducted to determine the dynamics of changes in the spore density of arbuscular mycorrhizal fungi (AMF) and of the degree of endomycorrhizal colonisation of roots of clovers and meadow grasses on an organic peat-muck soil in a post-marshy habitat, taking into account the effect of mineral fertilisation (NPK). The experimental object comprised four plots that represented the fertilisation treatments, sown with white clover (Trifolium repens L.), red clover (Trifolium pratense L.), smooth meadow-grass (Poa pratensis L.), and a mix of grasses composed of perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis Huds.), smooth meadow-grass (Poa pratensis L.), and cocksfoot (Dactylis glomerata L.). Analogous sowing was performed on control (non-fertilised) plots. It was found that spores of AMF occurred in 100 percent of the samples of the soil studied, and the average total number of AMF spores isolated from soil under the particular plant combinations was high and amounted to 1858 spores (range from 1392 to 2443) in 100 g of air-dried soil. The percentage share of the clover and grass roots colonised by indigenous endomycorrhizal fungi was very low and varied from 0 to 46 (average from 4.1 percent to 12.2 percent). No correlation was found between the spore numbers of AMF in the soil and the degree of mycorrhized roots of the clovers and grasses. Mineral fertilisation stimulated the sporulation of AM fungi but had no effect on root colonisation by these fungi. (author)
Short-term residual N unaffected by forbs in grass-clover mixtures
DEFF Research Database (Denmark)
Dhamala, Nawa Raj; Rasmussen, Jim; Cong, Wenfeng
2017-01-01
We determined the effect on residual nitrogen (N) of including forbs (chicory, ribwort plantain and caraway) in perennial ryegrass-red clover mixtures. Although soil N inputs during the grassland phase differed markedly between mixtures, in a pot experiment we found no differences...... in the potentially mineralizable N of the soil or in the dry matter production and N content of the spring barley test crop. The fertilizer value of the grassland mixtures corresponded to 10 g N/m2, irrespective of forb inclusion. Thus, the inclusion of nonlegume forbs did not negatively affect short-term residual N...
Characterization of Czochralski silicon detectors
Luukka, Panja-Riina
2006-01-01
This thesis describes the characterization of irradiated and non-irradiated segmented detectors made of high-resistivity (>1 kΩcm) magnetic Czochralski (MCZ) silicon. It is shown that the radiation hardness (RH) of the protons of these detectors is higher than that of devices made of traditional materials such as Float Zone (FZ) silicon or Diffusion Oxygenated Float Zone (DOFZ) silicon due to the presence of intrinsic oxygen (> 5 × 1017 cm−3). The MCZ devices therefore present an interesting ...
Energy Technology Data Exchange (ETDEWEB)
Howansky, A; Peng, B; Lubinsky, A; Zhao, W [Stony Brook University, Stony Brook, NY (United States)
2016-06-15
Purpose: Pulse height spectra (PHS) have been used to determine the Swank factor of a scintillator by measuring fluctuations in its light output per x-ray interaction. The Swank factor and x-ray quantum efficiency of a scintillator define the upper limit to its imaging performance, i.e. DQE(0). The Swank factor below the K-edge is dominated by optical properties, i.e. variations in light escape efficiency from different depths of interaction, denoted e(z). These variations can be optimized to improve tradeoffs in x-ray absorption, light yield, and spatial resolution. This work develops a quantitative model for interpreting measured PHS, and estimating e(z) on an absolute scale. The method is used to investigate segmented ceramic GOS scintillators used in multi-slice CT detectors. Methods: PHS of a ceramic GOS plate (1 mm thickness) and segmented GOS array (1.4 mm thick) were measured at 46 keV. Signal and noise propagation through x-ray conversion gain, light escape, detection by a photomultiplier tube and dynode amplification were modeled using a cascade of stochastic gain stages. PHS were calculated with these expressions and compared to measurements. Light escape parameters were varied until modeled PHS agreed with measurements. The resulting estimates of e(z) were used to calculate PHS without measurement noise to determine the inherent Swank factor. Results: The variation in e(z) was 67.2–89.7% in the plate and 40.2–70.8% in the segmented sample, corresponding to conversion gains of 28.6–38.1 keV{sup −1} and 17.1–30.1 keV{sup −1}, respectively. The inherent Swank factors of the plate and segmented sample were 0.99 and 0.95, respectively. Conclusion: The high light escape efficiency in the ceramic GOS samples yields high Swank factors and DQE(0) in CT applications. The PHS model allows the intrinsic optical properties of scintillators to be deduced from PHS measurements, thus it provides new insights for evaluating the imaging performance of
DEFF Research Database (Denmark)
Hansen, Elly Møller; Eriksen, Jørgen
2016-01-01
When grass-clover leys have been ploughed nitrate leaching may increase. However, management of leys before or after ploughing may affect the leaching risk. We examined the effect of cultivating a six year ley, which the last two years had been treated differently (grazing only; spring cut follow...
Effect of maturity and conservation of grass/clover on digestibility and rumen pH in heifers
DEFF Research Database (Denmark)
Koch, A.S.; Nørgaard, P.; Weisbjerg, Martin Riis
2013-01-01
The study aimed to evaluate effects of maturity and conservation of primary growth grass/clover on apparent digestibility and rumen pH. Two batches of mixed ryegrass, red and white clover harvested in 2009 on May 9 and 25 were conserved as either silage or hay. The forages early silage (ES) and hay...... (EH), and late silage (LS) and hay (LH) had DM contents of 45, 84, 25 and 83%, and NDF contents of 32, 44, 42 and 50% of DM, respectively. Forages were fed as sole feed to four Jersey heifers of 435±30 kg BW in a 4×4 Latin square experiment. Feeding level was 90% of individual ad libitum intake......, divided in two daily meals at 0800 and 1530 h. Potentially digestible NDF (DNDF) was determined after 288 h in situ. Apparent digestibility of OM and NDF was estimated using Cr3O2 as marker. Rumen fluid pH in the medial and ventral rumen was measured with 1 h intervals from 0730 to 1530 h. Data...
Simulated performance of the in-beam conversion-electron spectrometer, SPICE
Energy Technology Data Exchange (ETDEWEB)
Ketelhut, S., E-mail: ketelhut@triumf.ca [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 (Canada); Evitts, L.J.; Garnsworthy, A.B.; Bolton, C.; Ball, G.C.; Churchman, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 (Canada); Dunlop, R. [Department of Physics, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Hackman, G.; Henderson, R.; Moukaddam, M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 (Canada); Rand, E.T.; Svensson, C.E. [Department of Physics, University of Guelph, Guelph, Ontario, Canada N1G 2W1 (Canada); Witmer, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3 (Canada)
2014-07-01
The SPICE spectrometer is a new in-beam electron spectrometer designed to operate in conjunction with the TIGRESS HPGe Clover array at TRIUMF-ISAC. The spectrometer consists of a large area, annular, segmented lithium-drifted silicon electron detector shielded from the target by a photon shield. A permanent magnetic lens directs electrons around the photon shield to the detector. Experiments will be performed utilising Coulomb excitation, inelastic-scattering, transfer and fusion–evaporation reactions using stable and radioactive ion beams with suitable heavy-ion detection. Good detection efficiency can be achieved in a large energy range up to 3500 keV electron energy using several magnetic lens designs which are quickly interchangeable. COMSOL and Geant4 simulations have been used to maximise the detection efficiency. In addition, the simulations have guided the design of components to minimise the contributions from various sources of backgrounds.
Performance of an AGATA asymmetric detector
Energy Technology Data Exchange (ETDEWEB)
Boston, A.J. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom)], E-mail: ajboston@liv.ac.uk; Dimmock, M.R.; Unsworth, C.; Boston, H.C.; Cooper, R.J.; Grint, A.N.; Harkness, L.J. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Lazarus, I.H. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Jones, M.; Nolan, P.J.; Oxley, D.C. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Simpson, J. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Slee, M. [Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom)
2009-06-01
High-resolution gamma-ray detectors based on high-purity germanium crystals (HPGe) are one of the key workhorses of experimental nuclear science. The technical development of such detector technology has been dramatic in recent years. Large volume, high-granularity, electrically segmented HPGe detectors have been realised and a methodology to improve position sensitivity using pulse-shape analysis coupled with the novel technique of gamma-ray tracking has been developed. Collaborations have been established in Europe (Advanced GAmma Tracking Array (AGATA)) [J. Simpson, Acta Phys. Pol. B 36 (2005) 1383] and the USA (GRETA/GRETINA) [C.W. Beausang, Nucl. Instr. and Meth. B 204 (2003)] to build gamma-ray tracking spectrometers. This paper discusses the performance of the first AGATA asymmetric detector that has been tested at the University of Liverpool. The use of a fully digital data acquisition system has allowed detector charge pulse shapes from a selection of well-defined photon interaction positions to be analysed, yielding important information on the position sensitivity of the detector.
CHICO, a heavy ion detector for Gammasphere
International Nuclear Information System (INIS)
Simon, M.W.; Cline, D.; Wu, C.Y.; Gray, R.W.; Teng, R.; Long, C.
2000-01-01
A 4π position-sensitive heavy-ion detector system, CHICO, has been developed primarily for use in conjunction with the 4π γ-ray facility, Gammasphere. The CHICO detector comprises an array of 20 Parallel Plate Avalanche Counters (PPACs) covering 12 deg. <θ<85 deg. and 95 deg. <θ<168 deg. and 280 deg. in phi. The PPACs have segmented delay-line cathode boards, measuring the polar scattering angle θ to 1 deg., and segmented anodes, measuring the azimuthal angle phi with 9 deg. resolution, while measuring the time-of-flight difference with 500 ps resolution. For binary reactions the kinematics can be reconstructed from the measured information, allowing identification of the target- and projectile-like nuclei with a mass resolution of Δm/m∼5%. The measured masses, recoil velocities, and recoil angles allow correction for Doppler shift and assignment of individual γ-rays to decay of the correct reaction product. This paper describes the design, operation and performance of the CHICO detector. The powerful combination of CHICO plus Gammasphere provides new research opportunities for the study of nuclear structure and reactions
DEFF Research Database (Denmark)
Rasmussen, Jim; Kusliene, Gedrime; Jacobsen, Ole Stig
2013-01-01
that 15N also had a heterogeneous distribution (up to two orders of magnitude). Conclusion Bicarbonate can efficiently be used to introduce 14C or 13C into plant via the leaf-labeling method. Both 14C and 15N showed heterogeneous distribution in the plant, although the distribution of 15N was more even......Aims: Application of carbon (C) and nitrogen (N) isotopes is an essential tool to study C and N flows in plant-soil-microorganisms systems. When targeting single plants in a community the tracers need to be added via e.g., leaf-labeling or stem-feeding approaches. In this study we: (i) investigated...... if bicarbonate can be used to introduce 14C (or 13C) into white clover and ryegrass, and (ii) compared the patterns of 14C and 15N allocation in white clover and ryegrass to evaluate the homogeneity of tracer distribution after two alternative labeling approaches. Methods Perennial ryegrass and white clover were...
Kornfelt, L F; Nørgaard, P; Weisbjerg, M R
2013-06-01
The study examined the effects of harvest time of red and white clover silage on eating and ruminating activity and particle size distribution in feed boli, rumen content and faeces in cows. The clover crops were harvested at two stages of growth and ensiled in bales. Red clover crops had 36% and 45% NDF in dry matter (DM) at early (ER) and late (LR) harvest, respectively, and the white clover crops had 19% and 29% NDF in DM at the early (EW) and late (LW) harvest, respectively. The silages were fed restrictively (80% of ad libitum intake) twice daily to four rumen cannulated non-lactating Jersey cows (588 ± 52 kg) in a 4 × 4 Latin square design. Jaw movements (JM) were recorded for 96 h continuously. Swallowed boli, rumen mat, rumen fluid and faeces samples were collected, washed in nylon bags (0.01 mm pore size) and freeze-dried before dry sieving through 4.750, 2.360, 1.000, 0.500, 0.212 and 0.106 mm into seven fractions. The length (PL) and width (PW) values of rumen and faeces particles within each fraction were measured by use of image analysis. The eating activity (min/kg DM intake; P rumen mat (P rumen fluid (P rumen mat and faeces, but only one peak (mode 1) for PL values. There was no difference in the mean and mode 1 PW and PL value in rumen mat between the four treatments. The mean PL, mode PL, mode 2 PW and mean PW in faeces were highest for LR (P rumen mat and faeces particles are most likely related to the leaves and the stems/petioles. In conclusion, the mean total chewing activity per kg DM was lowest for the white clover silage and increased for both silages due to later harvest time. The mean particle size in boli was smallest for LR, whereas the mean PL and PW in faeces were highest for the LR.
User-guided segmentation for volumetric retinal optical coherence tomography images
Yin, Xin; Chao, Jennifer R.; Wang, Ruikang K.
2014-01-01
Abstract. Despite the existence of automatic segmentation techniques, trained graders still rely on manual segmentation to provide retinal layers and features from clinical optical coherence tomography (OCT) images for accurate measurements. To bridge the gap between this time-consuming need of manual segmentation and currently available automatic segmentation techniques, this paper proposes a user-guided segmentation method to perform the segmentation of retinal layers and features in OCT images. With this method, by interactively navigating three-dimensional (3-D) OCT images, the user first manually defines user-defined (or sketched) lines at regions where the retinal layers appear very irregular for which the automatic segmentation method often fails to provide satisfactory results. The algorithm is then guided by these sketched lines to trace the entire 3-D retinal layer and anatomical features by the use of novel layer and edge detectors that are based on robust likelihood estimation. The layer and edge boundaries are finally obtained to achieve segmentation. Segmentation of retinal layers in mouse and human OCT images demonstrates the reliability and efficiency of the proposed user-guided segmentation method. PMID:25147962
DEFF Research Database (Denmark)
Nielsen, Gunnar Gissel
1973-01-01
The uptake of added Se from selenite and selenate by barley and red clover was investigated in a pot experiment. Much more of selenate than of selenite was taken up but the Se concentrations in the plants declined more with time when selenate was the source. Increasing sulphate addition to the soil...
320-detector row CT coronary angiography in patients with arrhythmia
International Nuclear Information System (INIS)
Lu Li; Zhang Zhaoqi; Xu Lei; Yang Lin
2011-01-01
Objective: To evaluate the feasibility of CT coronary angiography (CTCA) in patients with arrhythmia using 320-detector row CT. Methods: Thirty-one patients with persistent atrial fibrillation and 8 patients with premature ventricular contraction were enrolled in this study. All patients underwent 320- detector row CTCA. CT image quality was evaluated with 4-point grading scale by two radiologists. Inter- observer agreement was evaluated by Kappa statistics. The radiation dose was calculated. Results: In total 510 coronary segments, 496 (97.2%) segments met diagnostic standard. The mean effective dose was (12.7±4.8) mSv in this study. There was a good agreement in image quality scoring between the two reviewers (Kappa = 0.72). Conclusion: 320-detector row CTCA is feasible in patients with atrial fibrillation and premature ventricular contraction. Arrhythmia may not be considered as a contraindication to CTCA. (authors)
Goldbach, Rob; Krijt, Jette
1982-01-01
The protease encoded by the large (B) RNA segment of cowpea mosaic virus was tested for its ability to recognize the in vitro translation products of the small (M) RNA segment from the comoviruses squash mosaic virus, red clover mottle virus, and cowpea severe mosaic virus (CPsMV, strains Dg and Ark), and from the nepovirus tomato black ring virus. Like M RNA from cowpea mosaic virus, the M RNAs from squash mosaic virus, red clover mottle virus, CPsMV-Dg, and CPsMV-Ark were all translated int...
Data acquisition for the HILI [Heavy Ion Light Ion] detector
International Nuclear Information System (INIS)
Teh, K.M.; Shapira, D.; McConnell, J.W.; Kim, H.; Novotny, R.
1987-01-01
A large acceptance, multi-segmented detector system capable of the simultaneous detection of heavy and light ions has been constructed. The heavy ions are detected with a segmented gas ionization chamber and a multiwire proportional counter while the light ions are detected with a 192 element plastic phoswich hodoscope. Processing the large number of signals is accomplished through a combination of CAMAC and FASTBUS modules and preprocessors, and a Host minicomputer. Details of the data acquisition system and the reasons for adopting a dual standards system are discussed. In addition, a technique for processing signals from an individual hodoscope detector is presented. 4 refs., 3 figs
The sixfold segmented MINIBALL module simulation and experiment
International Nuclear Information System (INIS)
Gund, C.
2000-01-01
MINIBALL, the new γ-ray spectrometer for REX-ISOLDE and other radioactive beam experiments consists of 42 encapsulated, six-fold segmented germanium modules of the EUROBALL geometry, clustered in cryostats of three modules (3-Cluster). The high full-energy-peak efficiency of the spectrometer allows γ-ray spectroscopy of low intensity beams, the high granularity permits a good energy resolution after Doppler correction, in spite of the high velocity of the γ-emitting reaction products. Detailed simulations were performed to investigate the physical limits of the detector granularity using the segment energies and pulse-shape analysis. Algorithms to locate the γ-ray entry point into the detector were developed. Special attention was paid to the application of these algorithms to the 3-Cluster detector. A position resolution of the γ-ray entry point of 10 mm x 10 mm was obtained and experimentally verified. Finally predictions for the energy resolution after Doppler correction were deduced. An experiment was performed to investigate the problems of low-intensity experiments in inverse kinematics. The use of the MINIBALL germanium modules in conjunction with the REX-ISOLDE PPAC allowed to solve these problems, a good energy resolution and a significant background suppression could be achieved. (orig.)
Gallegos, Gregory L.; Odom, William R.; Guikema, James A.
1995-01-01
The study of higher plant growth and development in the microgravity (micro-g) environment continues to be a challenge. This is in part a result of the available flight qualified hardware with restrictive closed gas environments. This point is underscored by considering that gas exchange of seedlings grown in microgravity may be further limited owing to a thicker layer of water wicked onto the roots and to the absence of convective mixing. We hypothesized that seedlings grown under such conditions will experience greater hypoxia in microgravity than at Earth gravity, and thus produce greater stress ethylene. We compared flight and ground samples of sweet clover seedlings grown in the Fluid Processing Apparatus (FPA) during STS-57 and found them to contain extremely high levels of carbon dioxide (CO2) and stress ethylene. There were time dependent increases for both gases, and seedling growth was greatly inhibited. We repeated these experiments aboard STS-60 using modified chambers which increased, by fifty fold, the air available to the developing seedlings. Sweet clover seed germination and subsequent seedling growth to eight days within the FPA modified with a gas permeable membrane is not compromised by the microgravity environment.
Iris segmentation using an edge detector based on fuzzy sets theory and cellular learning automata.
Ghanizadeh, Afshin; Abarghouei, Amir Atapour; Sinaie, Saman; Saad, Puteh; Shamsuddin, Siti Mariyam
2011-07-01
Iris-based biometric systems identify individuals based on the characteristics of their iris, since they are proven to remain unique for a long time. An iris recognition system includes four phases, the most important of which is preprocessing in which the iris segmentation is performed. The accuracy of an iris biometric system critically depends on the segmentation system. In this paper, an iris segmentation system using edge detection techniques and Hough transforms is presented. The newly proposed edge detection system enhances the performance of the segmentation in a way that it performs much more efficiently than the other conventional iris segmentation methods.
Forage production in mixed grazing systems of elephant grass with arrowleaf clover or forage peanut
Directory of Open Access Journals (Sweden)
Daiane Cristine Seibt
Full Text Available ABSTRACT Most dairy production systems are pasture-based, usually consisting of sole grass species. This system facilitates pasture management, but results in high production costs, mainly because of nitrogen fertilizers. An alternative to making forage systems more sustainable is to introduce legumes into the pasture. Mixed pastures allow better forage distribution over time and reduce fertilization costs. Thus, the objective of this study was to evaluate, throughout the year, three forage systems (FS: FS1 (control - elephant grass (EG, ryegrass (RG, and spontaneous species (SS; FS2 - EG + RG + SS + arrowleaf clover; and FS3 - EG + RG + SS + forage peanut. Elephant grass was planted in rows spaced 4 m apart. Ryegrass was sown between the EG lines, in the winter. Arrowleaf clover was sown according to the respective treatments and forage peanut was preserved. Evaluation was carried out using Holstein cows. The experiment was arranged in a completely randomized design, with three treatments (FS, and three repetitions (paddocks with repeated measurements (grazing cycles. Forage mass achieved 3.46, 3.80, and 3.91 t ha-1 for the treatments FS1, FS2 and FS3, respectively. The forage systems intercropped with legumes produced the best results.
A segmented detector for airbone gamma ray spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Burgada, G.; Iovene, A.; Petrucci, S.; Tintori, C., E-mail: g.burgada@caen.it [Costruzioni Apparecchiature Elettroniche Nucleari S.p.A. (CAEN), Viareggio (Italy); Alvarez, M.A.G., E-mail: malvarez@if.usp.br [Universidade de Sao Paulo (IF/USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Baldoncini, M.; Xhixha, G.; Strati, V., E-mail: gerti.xhixha@unife.it [University of Ferrara, Department of Physics and Earth Sciences, Ferrara (Italy); Mantovani, F., E-mail: mantovani@fe.infn.it [Istituto Nazionale di Fisica Nucleare (INFN), Ferrara (Italy); Garosi, P.; Mou, L., E-mail: li.mou@libero.it [University of Siena (Italy); Alvarez, C. Rossi, E-mail: rossialvarez@pd.infn.it [Istituto Nazionale di Fisica Nucleare (INFN), Legnaro (Italy)
2014-07-01
The airborne gamma-ray spectrometry (AGRS) is widely acknowledged as a very efficient technique for large areas monitoring. The detector system mounted on a helicopter allows for an extensive survey in a single flight time, thus reducing the exposure risk for the operator. Results from AGRS techniques are exploited in many fields, from the geological research to the homeland security for the search of orphan radioactive sources, from the mining and hydrocarbon exploration to the construction industry. The new generation of compact digital data acquisition and online processing equipment allows for faster airborne survey campaigns, and enhances the flexibility of operations. In addition, the algorithm for the extrapolation of the nuclide concentrations from the acquired gamma spectra is a challenging step of the entire technique. We are going to present a new device for advanced AGRS measurements, with an innovative detector configuration and data processing algorithms for optimizing the source localization and the on-line response capabilities. The new compact structure makes the system easily portable by a single operator, and rapidly mountable on most common helicopters. Preliminary feasibility studies have been performed to test the mechanics and the hardware of the whole system, which is intended to work without any human attendance. The first flights are planned by the end of 2014, with the aim of detecting artificial point sources having intensities on the order of 10^8 Bq and natural enriched fields already monitored. (author)
A segmented detector for airbone gamma ray spectroscopy
International Nuclear Information System (INIS)
Burgada, G.; Iovene, A.; Petrucci, S.; Tintori, C.; Alvarez, M.A.G.; Mantovani, F.; Garosi, P.; Mou, L.; Alvarez, C. Rossi
2014-01-01
The airborne gamma-ray spectrometry (AGRS) is widely acknowledged as a very efficient technique for large areas monitoring. The detector system mounted on a helicopter allows for an extensive survey in a single flight time, thus reducing the exposure risk for the operator. Results from AGRS techniques are exploited in many fields, from the geological research to the homeland security for the search of orphan radioactive sources, from the mining and hydrocarbon exploration to the construction industry. The new generation of compact digital data acquisition and online processing equipment allows for faster airborne survey campaigns, and enhances the flexibility of operations. In addition, the algorithm for the extrapolation of the nuclide concentrations from the acquired gamma spectra is a challenging step of the entire technique. We are going to present a new device for advanced AGRS measurements, with an innovative detector configuration and data processing algorithms for optimizing the source localization and the on-line response capabilities. The new compact structure makes the system easily portable by a single operator, and rapidly mountable on most common helicopters. Preliminary feasibility studies have been performed to test the mechanics and the hardware of the whole system, which is intended to work without any human attendance. The first flights are planned by the end of 2014, with the aim of detecting artificial point sources having intensities on the order of 10^8 Bq and natural enriched fields already monitored. (author)
International Nuclear Information System (INIS)
Misiakos, K.; Kavadias, S.
1996-01-01
A new radiation imaging device is proposed based on strips segmented into small pixels. Every pixel contains a submicron transistor that is normally biased in weak inversion. The ionization charge, upon collection by the pixel, changes the bias of the transistor to strong inversion and supplies a current up to several tens of a microA. This is a consequence of the small pixel capacitance (12 fF). The drains and sources of the transistors on the same row and column are shorted to bus lines that effectively become the Y and X coordinates. These bus lines are connected to the off chip ICON amplifiers to provide a 10 ns peaking time at a noise of about 150 electrons and 1 nW power consumption, for a 10x10 cm 2 detector and a MIP excitation. The noise performance is dominated by the ICON transistors. The cross talk between adjacent strips can be kept at a few percentage points provided a low transistor bias current is used
A note on the effects of paddock size on the white clover content of swards grazed by sheep
Wolf, de P.L.; Schulte, R.P.O.; Lantinga, E.A.
2004-01-01
The maintenance of a high white clover content in mixed swards under sheep grazing has been a challenge to date. This paper presents the results of an experiment in which the effect of the length of a grazing period on the botanical composition of a mixed sward was studied. Paddocks ranging in size
Energy Technology Data Exchange (ETDEWEB)
Xu, Lei; Yang, Lin; Fan, Zhanming; Yu, Wei; Lv, Biao; Zhang, Zhaoqi [Capital Medical University, Department of Radiology, Beijing Anzhen Hospital, Beijing (China)
2011-05-15
To evaluate the feasibility, diagnostic accuracy, and radiation dose of CT coronary angiography (CTCA) in patients with atrial fibrillation (AF) using 320-detector CT. Thirty-seven patients with persistent AF and suspected coronary artery disease (CAD) were enrolled. All patients underwent both 320-detector CTCA and conventional coronary angiography (CCA). CT image quality and the presence of significant ({>=}50%) stenosis were evaluated by two radiologists blinded to the results of CCA. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated using CCA as the reference standard. Differences in detection of coronary artery stenosis between 320-detector CTCA and CCA were evaluated with McNemar's test. Patient radiation dose was calculated by multiplying dose length product by conversion coefficient of 0.017. In total 474 evaluated coronary segments, 459 (96.8%) segments were diagnostically evaluable. On per-segment analysis, sensitivity, specificity, PPV and NPV were 90.0% (18 of 20), 99.3% (436 of 439), 85.7% (18 of 21) and 99.5% (436 of 438). No significant difference was found between 320-detector CTCA and CCA on the detection of significant stenosis (P = 1.000). Effective doses of 320-detector CTCA was 13.0 {+-} 4.7 mSv. 320-detector CTCA is feasible and accurate in excluding CAD in patients with AF. (orig.)
Campidonico, L; Toral, P G; Priolo, A; Luciano, G; Valenti, B; Hervás, G; Frutos, P; Copani, G; Ginane, C; Niderkorn, V
2016-04-01
This work investigated the effects of feeding silage mixtures of a plant containing polyphenol oxidase (PPO; red clover [; RC]), a plant containing tannins (sainfoin [; SF]), and a grass species not containing these compounds (timothy [; T]) on ruminal and intramuscular (i.m.) fatty acids of lambs. Forty 4-mo-old castrated male Romane lambs, divided into 5 groups, received 1 of the following silages: 1) T (100%), 2) a binary mixture of timothy and tannin-containing sainfoin ( cv. Perly; 50:50 [T-SF]), 3) a binary mixture of timothy and PPO-containing red clover ( cv. Mervius; 50:50 [T-RC]), 4) a ternary mixture of timothy, sainfoin, and red clover containing both tannins and PPO (50:25:25, respectively [T-SF-RC]), and 5) a binary mixture of tannin-containing sainfoin and PPO-containing red clover (50:50 [SF-RC]). In the rumen digesta, the partial or total replacement of T with forage legumes was associated with greater concentrations of PUFA ( forage legumes in the silage favored the accumulation of 18:3 -3 ( Forage legumes decreased the -11 18:1 to 30% of T in rumen digesta ( Forage legumes decreased the total concentration of branched-chain fatty acids in the rumen digesta (on average, -28%; comparison with T. The dietary treatment tended to affect the proportion of MUFA ( = 0.081) and of PUFA ( = 0.079) in the i.m. fat of the LM, respectively, at the highest and lowest numerical value in the T group. The sum of -3 fatty acids was less in the T and T-SF groups compared with the mixture of legumes without T (SF-RC; comparison with lambs given T-RC, T-SF-RC, and SF-RC. Rumenic acid (-9 -11 CLA) was detected at a greater percentage in the LM from the animals fed the T silage compared with animals fed the T-SF-RC treatment ( = 0.004). Contrarily, -9 -12 -15 18:3 was found at a greater concentration in the muscle from lambs in the SF-RC treatment compared with lambs in the other treatments ( forage for growing lambs in terms of i.m. fatty acid composition.
Performance of prototype segmented CdZnTe arrays
International Nuclear Information System (INIS)
Parsons, A.; Palmer, D.M.; Kurczynski, P.; Barbier, L.; Barthelmy, S.; Bartlett, L.; Gehrels, N.; Krizmanic, J.; Stahle, C.M.; Tueller, J.; Teegarden, B.
1998-01-01
The Burst and All Sky Imaging Survey (BASIS) is a proposed mission to provide ∼3 arc second locations of approximately 90 Gamma-Ray Bursts (GRBs) per year. The BASIS coded aperture imaging system requires a segmented detector plane able to detect the interaction position of (10--150 keV) photons to less than 100 microm. To develop prototype detector arrays with such fine position resolution the authors have fabricated many 15 mm x 15 mm x 2 mm 100 microm pitch CdZnTe strip detectors. They have assembled these fine pitch CdZnTe strip detectors into prototype 2 x 2 and 6 x 6 element arrays read out by ASIC electronics. The assembly and electronics readout of the 6 x 6 flight prototype array will be discussed, and preliminary data illustrating the uniformity and efficiency of the array will be presented
Fabrication, Quality Assurance, and Quality Control for PROSPECT Detector Component Production
Gustafson, Ian; Prospect (The Precision Reactor Oscillation; Spectrum Experiment) Collaboration
2017-09-01
The Precision Reactor Oscillation and Spectrum Experiment (PROSPECT) is an electron antineutrino (νe) detector intended to make a precision measurement of the 235U neutrino spectrum and to search for the possible existence of sterile neutrinos with a mass splitting of Δm2 on the order of 1 eV2 . As a short baseline detector, PROSPECT will be located less than 10 meters from the High Flux Isotope Reactor at Oak Ridge National Laboratory. As PROSPECT intends to search for baseline-dependent oscillations, physical segmentation is needed to better measure the interaction position. PROSPECT will therefore be a segmented detector in two dimensions, thereby improving position measurements. PROSPECT will be segmented into 154 (11×14) 1.2-meter long rectangular tubes, using optical separators. Each separator will consist of a carbon fiber core, laminated with optical reflector (to increase light collection) and Teflon (to ensure compatibility with the scintillator). These optical separators will be held in place via strings of 3D printed PLA rods called `pinwheels.' This poster discusses the fabrication and quality assurance (QA) procedures used in the production of both the PROSPECT optical separators and pinwheels. For the PROSPECT collaboration.
A highly-segmented neutron detector for the A1 experiment at MAMI
Energy Technology Data Exchange (ETDEWEB)
Schoth, Matthias [Institut fuer Kernphysik, Mainz (Germany); Collaboration: A1-Collaboration
2015-07-01
Electric and magnetic form factors of the neutron, are one of the defining properties to characterize its structure quantitatively. A planned physics program to improve the data base significantly requires high performance detection of relativistic neutrons. Exploiting the full potential of the high luminosity supplied by the MAMI accelerator, a novel neutron detector is being developed in the scope of the A1 collaboration. A large active detector volume of 0.96 m{sup 3} is required to achieve a high raw detection efficiency. The detector is subdivided into 2048 plastic scintillators to be able to cope with high background rates. The light is extracted via wavelength shifting fibres and then guided to multi anode photomultiplier. The signal is read out with FPGA based TDCs (TRBv3 developed at GSI). The energy of the signal is obtained via time over threshold information in combination with a suitable shaping and discriminating circuit. Prototype tests have been performed to optimize the choice of materials and geometry. The capability to detect neutrons in the relevant momentum range has been demonstrated using pion production. A Geant4 simulation using tracking algorithms evaluating the deposited energy is able to optimize key detector properties like particle id efficiency, multiplicity or the effective analyzing power for double polarized scattering experiments.
New uses of clover-grass mixtures in the structure of fodder crops on arable land
Directory of Open Access Journals (Sweden)
Jiří Sláma
2010-01-01
Full Text Available The use of clover-grasses in the structure of fodder crops grown on arable soil, especially those with intergeneric hybrids as the main component part, could avert the negative current trend, i.e. further decreasing the area of perennial fodder plants or fodder crops as a whole on arable soil. They have an irreplaceable role in crop sequences and in preserving the cultural character of the countryside, above all due to the fact that they improve soil fertility and microbial life in the soil and that they have an excellent pre-produce value, and, at the same time, they are applied in various farming systems (both conventional and ecological and in various climatic conditions, and agricultural businesses are well equipped for growing, harvesting and storing them. In the Czech Republic, the area of fodder crops grown on arable soil was decreased from 1,019.9 thousand hectares to mere 396.7 thousand hectares between 1980 and 2009, which is 15.6 % of the total area of arable soil whereas perennial fodder plants only take up 8.5 %. Fodder from clover crops and clover-grass growths on arable soil are one of the main resources of voluminous fodder for dairy cows. Most of this fodder is preserved through a fermentation process (silages, hay storage; a smaller part is fed as fresh fodder, or serves for production of hay. Silages made with perennial fodder plants are the most important source of both proteins and other nutrients for ruminants, especially for high-yielding milch cows. The basis of fodder production systems are the conservative elements of the landscape area (geomorphology in combination with the progressive elements (weather conditions, plants and human labour and relict ones, the representative of which is the soil. The fodder production systems in Europe are divided into five main fodder production zones. From this point of view, the areas where short-term clover-grass mixtures are grown on arable soil could be classed with Zone 4, i
Jiang, Jiyang; Liu, Tao; Zhu, Wanlin; Koncz, Rebecca; Liu, Hao; Lee, Teresa; Sachdev, Perminder S; Wen, Wei
2018-07-01
We present 'UBO Detector', a cluster-based, fully automated pipeline for extracting and calculating variables for regions of white matter hyperintensities (WMH) (available for download at https://cheba.unsw.edu.au/group/neuroimaging-pipeline). It takes T1-weighted and fluid attenuated inversion recovery (FLAIR) scans as input, and SPM12 and FSL functions are utilised for pre-processing. The candidate clusters are then generated by FMRIB's Automated Segmentation Tool (FAST). A supervised machine learning algorithm, k-nearest neighbor (k-NN), is applied to determine whether the candidate clusters are WMH or non-WMH. UBO Detector generates both image and text (volumes and the number of WMH clusters) outputs for whole brain, periventricular, deep, and lobar WMH, as well as WMH in arterial territories. The computation time for each brain is approximately 15 min. We validated the performance of UBO Detector by showing a) high segmentation (similarity index (SI) = 0.848) and volumetric (intraclass correlation coefficient (ICC) = 0.985) agreement between the UBO Detector-derived and manually traced WMH; b) highly correlated (r 2 > 0.9) and a steady increase of WMH volumes over time; and c) significant associations of periventricular (t = 22.591, p deep (t = 14.523, p < 0.001) WMH volumes generated by UBO Detector with Fazekas rating scores. With parallel computing enabled in UBO Detector, the processing can take advantage of multi-core CPU's that are commonly available on workstations. In conclusion, UBO Detector is a reliable, efficient and fully automated WMH segmentation pipeline. Copyright © 2018 Elsevier Inc. All rights reserved.
Quantitative historical change in bumblebee (Bombus spp. assemblages of red clover fields.
Directory of Open Access Journals (Sweden)
Yoko L Dupont
Full Text Available BACKGROUND: Flower visiting insects provide a vitally important pollination service for many crops and wild plants. Recent decline of pollinating insects due to anthropogenic modification of habitats and climate, in particular from 1950's onwards, is a major and widespread concern. However, few studies document the extent of declines in species diversity, and no studies have previously quantified local abundance declines. We here make a quantitative assessment of recent historical changes in bumblebee assemblages by comparing contemporary and historical survey data. METHODOLOGY/PRINCIPAL FINDINGS: We take advantage of detailed, quantitative historical survey data from the 1930's on bumblebee (Bombus spp. abundances and species composition in red clover (Trifolium pratense fields, an important floral resource and an attractant of all bumblebee species. We used the historical survey data as a pre-industrialization baseline, and repeated the same sampling protocol at nearly the same localities at present, hence setting up a historical experiment. We detected historical changes in abundances (bees/m(2 of both workers (the "pollinatory units" and queens (effective population size, in addition to species composition. In particular, long-tongued bumblebee species showed consistent and dramatic declines in species richness and abundances throughout the flowering season of red clover, while short-tongued species were largely unaffected. Of 12 Bombus species observed in the 1930's, five species were not observed at present. The latter were all long-tongued, late-emerging species. CONCLUSIONS/SIGNIFICANCE: Because bumblebees are important pollinators, historical changes in local bumblebee assemblages are expected to severely affect plant reproduction, in particular long-tubed species, which are pollinated by long-tongued bumblebees.
DEFF Research Database (Denmark)
Hellwing, Anne Louise Frydendahl; Weisbjerg, Martin Riis
and D, respectively. TMR forage DM consisted of 2/3 of one of the respective grass-clover silages and 1/3 maize silage, and concentrate (soya meal and wheat) proportion of DM was 20% (low) or 50% (high). Methane emissions from the cows were measured 20-22 hours in one of four chambers working after...
The GALATEA test facility and a first study of α-induced surface events in a germanium detector
Energy Technology Data Exchange (ETDEWEB)
Irlbeck, Sabine
2014-01-30
Germanium detectors are a choice technology in fundamental research. They are suitable for the search for rare events due to their high sensitivity and excellent energy resolution. As an example, the GERDA (GERmanium Detector Array) experiment searching for neutrinoless double beta decay is described. The observation of this decay would resolve the fundamental question whether the neutrino is its own antiparticle. Especially adapted detector technologies and low background rates needed to detect very rare events such as neutrinoless double beta decays are discussed. The identification of backgrounds originating from the interaction of radiation, especially α-particles, is a focus of this thesis. Low background experiments face problems from α-particles due to unavoidable surface contaminations of the germanium detectors. The segmentation of detectors is used to obtain information about the special characteristics of selected events. The high precision test stand GALATEA was especially designed for surface scans of germanium detectors. As part of this work, GALATEA was completed and commissioned. The final commissioning required major upgrades of the original design which are described in detail. Collimator studies with two commercial germanium detectors are presented. Different collimation levels for a β-source were investigated and crystal axis effects were examined. The first scan with an α-source of the passivated end-plate of a special 19-fold segmented prototype detector mounted in GALATEA is described. The α-induced surface events were studied and characterized. Crosstalk and mirror pulses seen in the segments of the germanium detector were analyzed. The detector studies presented in this thesis will help to further improve the design of germanium detectors for low background experiments.
The GALATEA test facility and a first study of α-induced surface events in a germanium detector
International Nuclear Information System (INIS)
Irlbeck, Sabine
2014-01-01
Germanium detectors are a choice technology in fundamental research. They are suitable for the search for rare events due to their high sensitivity and excellent energy resolution. As an example, the GERDA (GERmanium Detector Array) experiment searching for neutrinoless double beta decay is described. The observation of this decay would resolve the fundamental question whether the neutrino is its own antiparticle. Especially adapted detector technologies and low background rates needed to detect very rare events such as neutrinoless double beta decays are discussed. The identification of backgrounds originating from the interaction of radiation, especially α-particles, is a focus of this thesis. Low background experiments face problems from α-particles due to unavoidable surface contaminations of the germanium detectors. The segmentation of detectors is used to obtain information about the special characteristics of selected events. The high precision test stand GALATEA was especially designed for surface scans of germanium detectors. As part of this work, GALATEA was completed and commissioned. The final commissioning required major upgrades of the original design which are described in detail. Collimator studies with two commercial germanium detectors are presented. Different collimation levels for a β-source were investigated and crystal axis effects were examined. The first scan with an α-source of the passivated end-plate of a special 19-fold segmented prototype detector mounted in GALATEA is described. The α-induced surface events were studied and characterized. Crosstalk and mirror pulses seen in the segments of the germanium detector were analyzed. The detector studies presented in this thesis will help to further improve the design of germanium detectors for low background experiments.
The influence of phosphorus deficiency on growth and nitrogen fixation of white clover plants
Høgh-Jensen, Dr Henning; Schjoerring, Dr Jan K.; Soussana, Dr Jean-Francois
2002-01-01
The effects of P deficiency on growth, N2‐fixation and photosynthesis in white clover (Trifolium repens L.) plants were investigated using three contrasting relative addition rates of P, or following abrupt withdrawal of the P supply. Responses to a constant below‐optimum P supply rate consisted of a decline in N2‐fixation per unit root weight and a small reduction in the efficiency with which electrons were allocated to the reduction of N2 in nodules. Abrupt removal of P arrested nodule grow...
First runs with the ORPHEUS dark matter detector
Czapek, G; Hauser, M; Janos, S; Loaiza, P; Moser, U; Pretzl, K; Brandt, B V D; Konter, J A; Mango, S; Ebert, T; Kainer, K U; Knoop, K M
2002-01-01
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 mu m 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.
A study of the wet deposit and foliar uptake of iodine and strontium on rye-grass and clover
International Nuclear Information System (INIS)
Angeletti, Livio; Levi, Emilio; Commission of the European Communities, Ispra
1977-12-01
Foliar uptake of iodine and strontium by rye-grass and clover was studied as a function of aspersion intensities. At the same time, the contribution of root sorption to foliar uptake was measured. The effective half-lives of radionuclides of standing and harvested grass were also determined together with their uptake under the action of demineralized water aspersion [fr
RDM plunger setup with clover detectors
International Nuclear Information System (INIS)
Rohilla, Aman; Gupta, Chandan Kumar; Chamoli, S.K.; Singh, R.P.; Bala, Indu; Muralither, S.
2013-01-01
The knowledge of level lifetimes of the excited nuclear states provides deeper insight into the internal structure of the nucleus. The transition probabilities obtained form level lifetimes, give direct information about the wave functions of the two states involved in the electromagnetic decay of the nucleus
Schottky barrier CdTe(Cl) detectors for planetary missions
International Nuclear Information System (INIS)
Eisen, Yosef; Floyd, Samuel
2002-01-01
Schottky barrier cadmium telluride (CdTe) radiation detectors of dimensions 2mm x 2mm x 1mm and segmented monolithic 3cm x 3 cm x 1mm are under study at GSFC for future NASA planetary instruments. These instruments will perform x-ray fluorescence spectrometry of the surface and monitor the solar x-ray flux spectrum, the excitation source for the characteristic x-rays emitted from the planetary body. The Near Earth Asteroid Rendezvous (NEAR) mission is the most recent example of such a remote sensing technique. Its x-ray fluorescence detectors were gas proportional counters with a back up Si PIN solar monitor. Analysis of NEAR data has shown the necessity to develop a solar x-ray detector with efficiency extending to 30keV. Proportional counters and Si diodes have low sensitivity above 9keV. Our 2mm x 2mm x 1mm CdTe operating at -30 degree sign C possesses an energy resolution of 250eV FWHM for 55Fe with unit efficiency to up to 30keV. This is an excellent candidate for a solar monitor. Another ramification of the NEAR data is a need to develop a large area detector system, 20-30 cm2, with cosmic ray charged particle rejection, for measuring the characteristic radiation. A 3cm x 3cm x 1mm Schottky CdTe segmented monolithic detector is under investigation for this purpose. A tiling of 2-3 such detectors will result in the desired area. The favorable characteristics of Schottky CdTe detectors, the system design complexities when using CdTe and its adaptation to future missions will be discussed
Track segments in hadronic showers in a highly granular scintillator-steel hadron calorimeter
Adloff, C.; Chefdeville, M.; Drancourt, C.; Gaglione, R.; Geffroy, N.; Karyotakis, Y.; Koletsou, I.; Prast, J.; Vouters, G.; Francis, K.; Repond, J.; Schlereth, J.; Smith, J.; Xia, L.; Baldolemar, E.; Li, J.; Park, S.T.; Sosebee, M.; White, A.P.; Yu, J.; Eigen, G.; Mikami, Y.; Watson, N.K.; Mavromanolakis, G.; Thomson, M.A.; Ward, D.R.; Yan, W.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Dannheim, D.; Dotti, A.; Folger, G.; Ivantchenko, V.; Klempt, W.; Kraaij, E.van der; Lucaci-Timoce, A.-I; Ribon, A.; Schlatter, D.; Uzhinskiy, V.; Cârloganu, C.; Gay, P.; Manen, S.; Royer, L.; Tytgat, M.; Zaganidis, N.; Blazey, G.C.; Dyshkant, A.; Lima, J.G.R.; Zutshi, V.; Hostachy, J.-Y; Morin, L.; Cornett, U.; David, D.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Karstensen, S.; Krivan, F.; Krüger, K.; Lu, S.; Morozov, S.; Morgunov, V.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Feege, N.; Garutti, E.; Laurien, S.; Marchesini, I.; Matysek, M.; Ramilli, M.; Briggl, K.; Eckert, P.; Harion, T.; Schultz-Coulon, H.-Ch; Shen, W.; Stamen, R.; Bilki, B.; Norbeck, E.; Onel, Y.; Wilson, G.W.; Kawagoe, K.; Sudo, Y.; Yoshioka, T.; Dauncey, P.D.; Magnan, A.-M; Bartsch, V.; Wing, M.; Salvatore, F.; Gil, E.Cortina; Mannai, S.; Baulieu, G.; Calabria, P.; Caponetto, L.; Combaret, C.; Negra, R.Della; Grenier, G.; Han, R.; Ianigro, J-C; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Petrukhin, A.; Steen, A.; Tromeur, W.; Donckt, M.Vander; Zoccarato, Y.; Alamillo, E.Calvo; Fouz, M.-C; Puerta-Pelayo, J.; Corriveau, F.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Popov, V.; Rusinov, V.; Tarkovsky, E.; Kirikova, N.; Kozlov, V.; Smirnov, P.; Soloviev, Y.; Buzhan, P.; Ilyin, A.; Kantserov, V.; Kaplin, V.; Karakash, A.; Popova, E.; Tikhomirov, V.; Kiesling, C.; Seidel, K.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Amjad, M.S.; Bonis, J.; Callier, S.; Lorenzo, S.Conforti di; Cornebise, P.; Doublet, Ph; Dulucq, F.; Fleury, J.; Frisson, T.; der Kolk, N.van; Li, H.; Martin-Chassard, G.; Richard, F.; Taille, Ch de la; Pöschl, R.; Raux, L.; Rouëné, J.; Seguin-Moreau, N.; Anduze, M.; Balagura, V.; Boudry, V.; Brient, J-C; Cornat, R.; Frotin, M.; Gastaldi, F.; Guliyev, E.; Haddad, Y.; Magniette, F.; Musat, G.; Ruan, M.; Tran, T.H.; Videau, H.; Bulanek, B.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Belhorma, B.; Ghazlane, H.; Kotera, K.; Takeshita, T.; Uozumi, S.; Jeans, D.; Götze, M.; Sauer, J.; Weber, S.; Zeitnitz, C.
2013-01-01
We investigate the three dimensional substructure of hadronic showers in the CALICE scintillator-steel hadronic calorimeter. The high granularity of the detector is used to find track segments of minimum ionising particles within hadronic showers, providing sensitivity to the spatial structure and the details of secondary particle production in hadronic cascades. The multiplicity, length and angular distribution of identified track segments are compared to GEANT4 simulations with several different shower models. Track segments also provide the possibility for in-situ calibration of highly granular calorimeters.
Electronics for the RHIC PHENIX detector
International Nuclear Information System (INIS)
Young, G.R.
1992-01-01
The PHENIX detector for RHIC is being designed to measure lepton pairs, direct photons and hadrons emitted in collisions of heavy nuclei at center of mass energies up to 200 GeV/(nucleon-pair). The physics goal is tests of predictions concerning the existence and nature of a deconfined state of strongly-interacting matter. The relatively large final state multiplicities, which reach 1500 charged particles per unit of rapidity, place strong demands on detector segmentation and control of electronics cost and power consumption. An overview of present ideas concerning signal processing and data rates for PHENIX will be presented
DEFF Research Database (Denmark)
Müller-Stöver, Dorette Sophie; Hauggaard-Nielsen, Henrik; Eriksen, Jørgen
2012-01-01
A laboratory incubation study with clover grass pasture soils of seven different ages (0, 1, 2, 3, 4, 5, and 16 production years) was carried out to determine initial soil carbon (C) and nitrogen (N) stocks and potentials for greenhouse gas emissions (N2O and CO2). Compared with the soil from...... the recently established pasture, an increase of total soil C and N was observed along with pasture age. Greenhouse gas emissions were low and not significantly different among the soils from younger pastures (0-5 years), but especially N2O emissions increased markedly in the soil from 16-year-old grass......-clover. Low emissions might mainly be due to an early C limitation occurring in the soils from younger pastures, which was also corroborated by decreasing levels of cold water-extractable C and early shifts within the microbial community. However, higher emissions from the old pasture soil were offset by its...
Superpixel-based segmentation of muscle fibers in multi-channel microscopy.
Nguyen, Binh P; Heemskerk, Hans; So, Peter T C; Tucker-Kellogg, Lisa
2016-12-05
Confetti fluorescence and other multi-color genetic labelling strategies are useful for observing stem cell regeneration and for other problems of cell lineage tracing. One difficulty of such strategies is segmenting the cell boundaries, which is a very different problem from segmenting color images from the real world. This paper addresses the difficulties and presents a superpixel-based framework for segmentation of regenerated muscle fibers in mice. We propose to integrate an edge detector into a superpixel algorithm and customize the method for multi-channel images. The enhanced superpixel method outperforms the original and another advanced superpixel algorithm in terms of both boundary recall and under-segmentation error. Our framework was applied to cross-section and lateral section images of regenerated muscle fibers from confetti-fluorescent mice. Compared with "ground-truth" segmentations, our framework yielded median Dice similarity coefficients of 0.92 and higher. Our segmentation framework is flexible and provides very good segmentations of multi-color muscle fibers. We anticipate our methods will be useful for segmenting a variety of tissues in confetti fluorecent mice and in mice with similar multi-color labels.
arXiv On the localization properties of an RPWELL gas-avalanche detector
Moleri, Luca; Coimbra, Artur E. C.; Breskin, Amos; Bressler, Shikma
2017-10-23
A study of the localization properties of a single-element Resistive Plate WELL (RPWELL) detector is presented. The detector comprises of a single-sided THick Gaseous Electron Multiplier (THGEM) coupled to a segmented readout anode through a doped silicate-glass plate of 10(10) Ω⋅cm bulk resistivity. Operated in ambient \
Application of position-sensitive detectors to positron imaging
International Nuclear Information System (INIS)
Yamashita, Takaji; Uchida, Hiroshi; Watanabe, Mitsuo; Omura, Tomohide
1994-01-01
Positron imaging including positron emission tomography (PET) is expected to be a promising tool for basic and clinical research, because it makes possible the study of regional chemistry within multiple organs of the body in living human beings and experimental animals. New schemes of high resolution block detectors have been developed to improve the performance of positron imaging systems, which employ small segments of bismuth germanate (BGO) arrays and position-sensitive photomultiplier tubes (PS-PMT). The coincidence detector resolution of less than 2.0 mm in full width at half maximum was achieved with the detectors, which is very close to the theoretical resolution limit in positron imaging. (author)
CHICO, a heavy ion detector for Gammasphere
Simon, M W; Wu, C Y; Gray, R W; Teng, R; Long, C
2000-01-01
A 4 pi position-sensitive heavy-ion detector system, CHICO, has been developed primarily for use in conjunction with the 4 pi gamma-ray facility, Gammasphere. The CHICO detector comprises an array of 20 Parallel Plate Avalanche Counters (PPACs) covering 12 deg.
Status of the KATRIN focal-plane detector
Energy Technology Data Exchange (ETDEWEB)
Seher, Agnes [Karlsruher Institute of Technology (KIT) (Germany). Institut fuer Kernphysik (IKP); Collaboration: KATRIN-Collaboration
2016-07-01
The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to determine the mass of the electron anti-neutrino with a sensitivity of 200 meV/c{sup 2} by measuring the kinematics of tritium β-electrons close to the enpoint of the energy spectrum. The energy analysis of the experiment is performed with a high-resolution electrostatic spectrometer of MAC-E filter type which acts as an integranting high pass filter. Transmitted electrons are counted with a segmented silicon detector system located at the downstream end of the experiment. The detector system consists of two super-conducting solenoids (B{sub max}=6 T), a post-acceleration electrode, a detector wafer with silicon pixel-diodes, readout electronics as well as a calibration and monitoring devices. This talk gives an overview of the detector system and its current status as well as key performance parameters.
Lin, XG.; Hao, WY.; Wu, TH.
1993-01-01
Investigation on the effect of phosphorus on vesicular-arbuscular mycorrhizal infection, and dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover under field microplots and pot experiments was conducted on fluvo-aquic soils of semi-arid region in north China. The results showed that 60 kg P205 ha in form of superphosphate was the most favorable phosphorus level for vesicular-arbuscular mycorrhizal infection ; mycorrhizal infection, nodulation, dry weight ...
Directory of Open Access Journals (Sweden)
Thomas Ann
2009-07-01
Full Text Available Abstract Background Polyphenol oxidase (PPO activity in plants is a trait with potential economic, agricultural and environmental impact. In relation to the food industry, PPO-induced browning causes unacceptable discolouration in fruit and vegetables: from an agriculture perspective, PPO can protect plants against pathogens and environmental stress, improve ruminant growth by increasing nitrogen absorption and decreasing nitrogen loss to the environment through the animal's urine. The high PPO legume, red clover, has a significant economic and environmental role in sustaining low-input organic and conventional farms. Molecular markers for a range of important agricultural traits are being developed for red clover and improved knowledge of PPO genes and their structure will facilitate molecular breeding. Results A bacterial artificial chromosome (BAC library comprising 26,016 BAC clones with an average 135 Kb insert size, was constructed from Trifolium pratense L. (red clover, a diploid legume with a haploid genome size of 440–637 Mb. Library coverage of 6–8 genome equivalents ensured good representation of genes: the library was screened for polyphenol oxidase (PPO genes. Two single copy PPO genes, PPO4 and PPO5, were identified to add to a family of three, previously reported, paralogous genes (PPO1–PPO3. Multiple PPO1 copies were identified and characterised revealing a subfamily comprising three variants PPO1/2, PPO1/4 and PPO1/5. Six PPO genes clustered within the genome: four separate BAC clones could be assembled onto a predicted 190–510 Kb single BAC contig. Conclusion A PPO gene family in red clover resides as a cluster of at least 6 genes. Three of these genes have high homology, suggesting a more recent evolutionary event. This PPO cluster covers a longer region of the genome than clusters detected in rice or previously reported in tomato. Full-length coding sequences from PPO4, PPO5, PPO1/5 and PPO1/4 will facilitate
DEFF Research Database (Denmark)
Johansen, Marianne; Lund, Peter; Weisbjerg, Martin Riis
2018-01-01
Our previous study showed that supply of metabolisable protein (MP) to lactating dairy cows increased with increasing dry matter (DM) concentration in grass-clover silage. The aim of this study was to examine how amino acid (AA) profile of MP was affected by silage DM concentration. Eight grass-c...
Lapenna, Elisabetta; De Bonis, Michele; Verzini, Alessandro; La Canna, Giovanni; Ferrara, David; Calabrese, Maria Chiara; Taramasso, Maurizio; Alfieri, Ottavio
2010-06-01
This study assesses the results of the 'clover technique' (suturing together the middle point of the free edges of the tricuspid leaflets) for the treatment of tricuspid regurgitation (TR) due to severe prolapse or tethering. From 2001, 66 patients with severe TR due to prolapsing or tethered leaflets underwent 'clover repair'. Annuloplasty was associated in 64 patients (97%). The aetiology of TR was degenerative in 52 cases (79%), post-traumatic in eight (12%) and secondary to dilated cardiomyopathy (DCM) in six (9%). The main mechanism of TR was prolapse/flail of one leaflet in 15 patients (23%), of two leaflets in 31 (47%) and of all three leaflets in 14 (21%). The remaining six patients (9%) presented with severe leaflets' tethering. Four deaths (6%) occurred during hospitalisation and one patient died 3.6 years after surgery. Survival was 91 + or - 4.1% at 5 years. Follow-up of the 62 hospital survivors was 100% complete (mean length 3.5 + or - 1.6 years, range 13 months-7.1 years). At the last echocardiogram, no or mild TR was detected in 55 (88.7%) patients, moderate (2+/4+) in six (9.6%) and severe (4+/4+) in one patient (1.6%). Mean tricuspid valve area and gradient were 4.3 + or - 0.6 cm(2) and 2.8 + or -1.4 mmHg. In six patients, stress echocardiography was performed and no signs of tricuspid stenosis were detected. At the multivariable analysis, the degree of TR at hospital discharge was identified as the only predictor of TR > or = 2+ at follow-up. Midterm clinical and echocardiographic results confirm the role of the 'clover technique' in the surgical treatment of TR due to lesions, which are unlikely to be effectively treatable by annuloplasty alone. Copyright 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.
A large, high performance, curved 2D position-sensitive neutron detector
Fried, J W; Mahler, G J; Makowiecki, D S; Mead, J A; Radeka, V; Schaknowski, N A; Smith, G C; Yu, B
2002-01-01
A new position-sensitive neutron detector has been designed and constructed for a protein crystallography station at LANL's pulsed neutron source. This station will be one of the most advanced instruments at a major neutron user facility for protein crystallography, fiber and membrane diffraction. The detector, based on neutron absorption in sup 3 He, has a large sensitive area of 3000 cm sup 2 , angular coverage of 120 deg. , timing resolution of 1 mu s, rate capability in excess of 10 sup 6 s sup - sup 1 , position resolution of about 1.5 mm FWHM, and efficiency >50% for neutrons of interest in the range 1-10 A. Features that are key to these remarkable specifications are the utilization of eight independently operating segments within a single gas volume, fabrication of the detector vessel and internal segments with a radius of curvature of about 70 cm, optimized position readout based on charge division and signal shaping with gated baseline restoration, and engineering design with high-strength aluminum ...
The ALICE Transition Radiation Detector: status and perspectives for Run II
Klein, Jochen
2016-01-01
The ALICE Transition Radiation Detector contributes to the tracking, particle identification, and triggering capabilities of the experiment. It is composed of six layers of multi-wire proportional chambers, each of which is preceded by a radiator and a Xe/CO$_2$-filled drift volume. The signal is sampled in timebins of 100~ns over the drift length which allows for the reconstruction of chamber-wise track segments, both online and offline. The particle identification is based on the specific energy loss of charged particles and additional transition radiation photons, the latter being a signature for electrons. The detector is segmented into 18 sectors, of which 13 were installed in Run I. The TRD was included in data taking since the LHC start-up and was successfully used for electron identification and triggering. During the Long Shutdown 1, the detector was completed and now covers the full azimuthal acceptance. Furthermore, the readout and trigger components were upgraded. When data taking was started for ...
Detector Simulations with DD4hep
Petrič, M.; Frank, M.; Gaede, F.; Lu, S.; Nikiforou, N.; Sailer, A.
2017-10-01
Detector description is a key component of detector design studies, test beam analyses, and most of particle physics experiments that require the simulation of more and more different detector geometries and event types. This paper describes DD4hep, which is an easy-to-use yet flexible and powerful detector description framework that can be used for detector simulation and also extended to specific needs for a particular working environment. Linear collider detector concepts ILD, SiD and CLICdp as well as detector development collaborations CALICE and FCal have chosen to adopt the DD4hep geometry framework and its DDG4 pathway to Geant4 as its core simulation and reconstruction tools. The DDG4 plugins suite includes a wide variety of input formats, provides access to the Geant4 particle gun or general particles source and allows for handling of Monte Carlo truth information, eg. by linking hits and the primary particle that caused them, which is indispensable for performance and efficiency studies. An extendable array of segmentations and sensitive detectors allows the simulation of a wide variety of detector technologies. This paper shows how DD4hep allows to perform complex Geant4 detector simulations without compiling a single line of additional code by providing a palette of sub-detector components that can be combined and configured via compact XML files. Simulation is controlled either completely via the command line or via simple Python steering files interpreted by a Python executable. It also discusses how additional plugins and extensions can be created to increase the functionality.
Schulze, A K S; Weisbjerg, M R; Storm, A C; Nørgaard, P
2014-06-01
The objective of this study was to investigate the effect of NDF content in highly digestible grass/clover silage on particle size reduction, ruminal stratification, and selective retention in dairy heifers. The reduction in particle size from feed to feces was evaluated and related to feed intake, chewing activity, and apparent digestibility. Four grass/clover harvests (Mixtures of Lolium perenne, Trifolium pratense, and Trifolium repens) were performed from early May to late August at different maturities, at different regrowth stages, and with different clover proportions, resulting in silages with NDF contents of 312, 360, 371, and 446 g/kg DM, respectively, and decreasing NDF digestibility with greater NDF content. Four rumen-fistulated dairy heifers were fed silage at 90% of ad libitum level as the only feed source in a 4 × 4 Latin square design. Silage, ingested feed boluses, medial and ventral ruminal digesta, and feces samples were washed with neutral detergent in nylon bags of 10-μm pore size, freeze dried, and divided into small (1 mm) particles by dry-sieving. Chewing activity, rumen pool size, and apparent digestibility were measured. Intake of NDF increased linearly from 2.3 to 2.8 kg/d with greater NDF content of forages (P = 0.01), but silages were exposed to similar eating time (P = 0.55) and rumination time per kg NDF (P = 0.35). No linear effect of NDF content was found on proportion of LP in ingested feed boluses (P = 0.31), medial rumen digesta (P = 0.95), ventral rumen digesta (P = 0.84), and feces (P = 0.09). Greater proportions of DM (P ruminal digesta compared with ventral rumen, and differences in DM proportion increased with greater NDF content (P = 0.02). Particle size distributions were similar for digesta from the medial and ventral rumen regardless of NDF content of the silages (P > 0.13). The LP proportion was >30% of particles in the ventral and medial rumen, whereas in the feces, the LP proportion was content of the silages
International Nuclear Information System (INIS)
Kshetri, R
2012-01-01
In two recent papers (R. Kshetri, JINST 2012 7 P04008; ibid., P07006), a probabilistic formalism was introduced to predict the response of encapsulated type composite germanium detectors like the SPI (spectrometer for INTEGRAL satellite). Predictions for the peak-to-total and peak-to-background ratios are given at 1.3 MeV for the addback mode of operation. The application of the formalism to clover germanium detector is discussed in two separate papers (R. Kshetri, JINST 2012 7 P07008; ibid., P08015). Using the basic approach developed in those papers, for the first time we present a procedure for calculating the peak-to-total ratio of the cluster detector for γ-energies up to 8 MeV. Results are shown for both bare and suppressed detectors as well as for the single crystal and addback modes of operation. We have considered the experimental data of (i) peak-to-total ratio at 1.3 MeV, and (ii) single detector efficiency and addback factor for other energies up to 8 MeV. Using this data, an approximate method of calculating the peak-to-total ratio of other composite detectors, is shown. Experimental validation of our approach (for energies up to 8 MeV) has been confirmed considering the data of the SPI spectrometer. We have discussed about comparisons between various modes of operation and suppression cases. The present paper is the fifth in the series of papers on composite germanium detectors and for the first time discusses about the change in fold distribution and peak-to-total ratio for sophisticated detectors consisting of several modules of miniball, cluster and SPI detectors. Our work could provide a guidance in designing new composite detectors and in performing experimental studies with the existing detectors for high energy gamma-rays.
Kshetri, R.
2012-12-01
In two recent papers (R. Kshetri, JINST 2012 7 P04008; ibid., P07006), a probabilistic formalism was introduced to predict the response of encapsulated type composite germanium detectors like the SPI (spectrometer for INTEGRAL satellite). Predictions for the peak-to-total and peak-to-background ratios are given at 1.3 MeV for the addback mode of operation. The application of the formalism to clover germanium detector is discussed in two separate papers (R. Kshetri, JINST 2012 7 P07008; ibid., P08015). Using the basic approach developed in those papers, for the first time we present a procedure for calculating the peak-to-total ratio of the cluster detector for γ-energies up to 8 MeV. Results are shown for both bare and suppressed detectors as well as for the single crystal and addback modes of operation. We have considered the experimental data of (i) peak-to-total ratio at 1.3 MeV, and (ii) single detector efficiency and addback factor for other energies up to 8 MeV. Using this data, an approximate method of calculating the peak-to-total ratio of other composite detectors, is shown. Experimental validation of our approach (for energies up to 8 MeV) has been confirmed considering the data of the SPI spectrometer. We have discussed about comparisons between various modes of operation and suppression cases. The present paper is the fifth in the series of papers on composite germanium detectors and for the first time discusses about the change in fold distribution and peak-to-total ratio for sophisticated detectors consisting of several modules of miniball, cluster and SPI detectors. Our work could provide a guidance in designing new composite detectors and in performing experimental studies with the existing detectors for high energy gamma-rays.
Image feature detectors and descriptors foundations and applications
Hassaballah, Mahmoud
2016-01-01
This book provides readers with a selection of high-quality chapters that cover both theoretical concepts and practical applications of image feature detectors and descriptors. It serves as reference for researchers and practitioners by featuring survey chapters and research contributions on image feature detectors and descriptors. Additionally, it emphasizes several keywords in both theoretical and practical aspects of image feature extraction. The keywords include acceleration of feature detection and extraction, hardware implantations, image segmentation, evolutionary algorithm, ordinal measures, as well as visual speech recognition. .
Report on the intercomparison run IAEA-156 radionuclides in clover
International Nuclear Information System (INIS)
Strachnov, V.; Valkovic, V.; Dekner, R.
1991-01-01
This report contains the results of the intercomparison IAEA-156 on the determination of radionuclides in clover. Initially participants were requested to determine the levels of 134 Cs, 137 Cs, 40 K, 90 Sr and invited to provide data for other radionuclides. The participants included 46 laboratories located in 25 countries, and statistical evaluation of their data yield recommended values for these four radionuclides. Additional radionuclides reported were 210 Pb, 239 Pu and 125 Sb; however, insufficient data exists to statistically determine recommended values for these radionuclides. The following are the recommended values, with confidence intervals, for the most frequently measured radionuclides (reference date: 1 August 1986): 134 Cs 132.1 Bq/kg (126.4-137.7); 137 Cs 264 Bq/kg (254-274); 40 K 657 Bq/kg (637-676); 90 Sr 14.8 Bq/kg (13.4-16.3). Figs and tabs
Two prairie-clovers, Dalea ornata and D. searlsiae, are perennial forbs that flower during early summer throughout the Colombia Plateau and Great Basin of the western USA, respectively. Their seed is desirable for use in rangeland restoration. We experimentally characterized the breeding biologies ...
Goldbach, R; Krijt, J
1982-09-01
The protease encoded by the large (B) RNA segment of cowpea mosaic virus was tested for its ability to recognize the in vitro translation products of the small (M) RNA segment from the comoviruses squash mosaic virus, red clover mottle virus, and cowpea severe mosaic virus (CPsMV, strains Dg and Ark), and from the nepovirus tomato black ring virus. Like M RNA from cowpea mosaic virus, the M RNAs from squash mosaic virus, red clover mottle virus, CPsMV-Dg, and CPsMV-Ark were all translated into two large polypeptides with apparent molecular weights which were different for each virus and even for the two CPsMV strains. Neither the in vitro products from squash mosaic virus, red clover mottle virus, and CPsMV M RNAs nor the in vitro product from tomato black ring virus RNA-2 were processed by the cowpea mosaic virus-encoded protease, indicating that the activity of this enzyme is highly specific.
The presampler for the forward and rear calorimeter in the ZEUS detector
Energy Technology Data Exchange (ETDEWEB)
Bamberger, A; Bornheim, A; Crittenden, J; Grabosch, H -J; Grothe, M; Hervas, L; Hilger, E; Holm, U; Horstmann, D; Kaufmann, V; Kharchilava, A; Koetz, U; Kummerow, D; Mallik, U; Meyer, A; Nowoczyn, M; Ossowski, R; Schlenstedt, S; Tiecke, H; Verkerke, W; Vossebeld, J; Vreeswijk, M; Wang, S M; Wu, J [Bonn Univ. (Germany). Phys. Inst.; [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); [DESY-IfH Zeuthen, Zeuthen (Germany); [Fakultaet fuer Physik der Universitaet Freiburg, Freiburg i.Br. (Germany); [Hamburg University, I. Institute of Exp. Physics, Hamburg (Germany); [University of Iowa Physics and Astronomy Dept, Iowa City (United States); [Univer. Autonoma Madrid, Depto de Fisica Teorica, Madrid (Spain); [NIKHEF and University of Amsterdam, Amsterdam (Netherlands)
1996-11-21
The ZEUS detector at HERA has been supplemented with a presampler detector in front of the forward and rear calorimeters. It consists of a segmented scintillator array read out with wavelength-shifting fibers. We discuss its design, construction and performance. Test beam data obtained with a prototype presampler and the ZEUS prototype calorimeter demonstrate the main function of this detector, i.e. the correction for the energy lost by an electron interacting in inactive material in front of the calorimeter. (orig.).
Utilization of kura clover-reed canarygrass silage versus alfalfa silage by lactating dairy cows.
Kammes, K L; Heemink, G B H; Albrecht, K A; Combs, D K
2008-08-01
The mixture of kura clover (Trifolium ambiguum M. Bieb.) and reed canarygrass (Phalaris arundinacea L.) has proven to be extremely persistent in the northern United States, but information about dairy cow performance on this mixture is lacking. Twenty lactating Holstein cows were used in a crossover design to compare dry matter (DM) intake and milk production from diets containing kura clover-reed canarygrass silage (KRS) or alfalfa (Medicago sativa L.) silage (AS). Forages were cut, wilted, ensiled in horizontal plastic bags, and allowed to ferment for at least 50 d before beginning the feeding experiment. The KRS was approximately 40% kura clover and 60% reed canarygrass. Treatments were total mixed rations formulated with either 57% of total DM from 1) AS or 2) KRS. Experimental periods were 28 d, with the first 14 d for diet adaptation and the last 14 d for measurement of intake and milk production. The neutral detergent fiber (NDF) concentrations of AS and KRS were 37.3 and 47.3%, respectively. The fermentation analyses indicated that both silages underwent a restricted fermentation, producing primarily lactic acid and some acetic acid. Dry matter intake (24.2 vs. 22.8 kg) and 4% fat-corrected milk (32.8 vs. 30.9 kg) were significantly higher for cows fed AS than for cows fed KRS. Cows consumed less NDF (6.7 vs. 8.0 kg) and less digestible NDF (3.0 vs. 4.4 kg) when fed AS diets compared with KRS diets, but the pool of ruminally undegraded NDF was similar (3.7 kg) between diets. Cows produced 1.5 kg of milk/kg of DM consumed regardless of the diet, indicating that digestible NDF of KRS was utilized with similar efficiency as the cell wall constituents of AS, but the intake of cows fed KRS may have been limited by rumen fill. Milk fat concentration tended to be higher for cows fed AS, but the milk true protein concentration and yields of fat and protein did not differ by treatment. Milk urea nitrogen content was higher when cows consumed AS (16.4 mg/ d
A contrario line segment detection
von Gioi, Rafael Grompone
2014-01-01
The reliable detection of low-level image structures is an old and still challenging problem in computer vision. This?book leads a detailed tour through the LSD algorithm, a line segment detector designed to be fully automatic. Based on the a contrario framework, the algorithm works efficiently without the need of any parameter tuning. The design criteria are thoroughly explained and the algorithm's good and bad results are illustrated on real and synthetic images. The issues involved, as well as the strategies used, are common to many geometrical structure detection problems and some possible
Simulation of TIFR-INGA array: present and future possibilities
International Nuclear Information System (INIS)
Saha, Sudipta; Palit, R.; Sethi, J.; Biswas, S.; Singh, P.
2016-01-01
Discrete γ-ray spectroscopy using large array of high purity germanium detectors continue to provide new insights to the structure of an atomic nucleus and its dynamics. The Indian National Gamma Array (INGA) at Tata Institute of Fundamental Research (TIFR) is a powerful spectrometer with a provision of placing 24 Compton suppressed clovers, mounted at different angles with respect to the beam line. A Geant4 based code has been developed to study various features of the array which are of general interest in γ-ray spectroscopy study. Response of the clover detectors have been tested up to 4.8 keV. For the first time geometrical correction factor required in angular distribution, angular correlation measurements have been extracted. The efficiency and add back factor of clover detectors have been successfully reproduced in the simulation. Good agreement has been obtained in simulated and experimental spectrum providing very accurate background estimation even at low energies. Simulations have also been carried out to introduce the concept of a multiplicity filter within the scope of present INGA assembly. In this context some relevant experimental measurements where there can be potential scope of using the simulation results will be discussed
International Nuclear Information System (INIS)
Manghat, N.E.; Morgan-Hughes, G.J.; Broadley, A.J.; Undy, M.B.; Wright, D.; Marshall, A.J.; Roobottom, C.A.
2006-01-01
Aim: To evaluate the diagnostic accuracy of 16-detector row computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients under evaluation for aortic stenosis pre-aortic valve replacement. Subjects and methods: Forty consecutive patients under evaluation for severe aortic stenosis and listed for cardiac catheterization before potential aortic valve replacement underwent coronary artery calcium (CAC) scoring and retrospective electrocardiogram (ECG)-gated multi-detector row computed tomographic coronary angiography (MDCTA) using a GE Lightspeed 16-detector row CT within 1 month of invasive coronary angiography (ICA) for comparative purposes. All 13 major coronary artery segments of the American Heart Association model were evaluated for the presence of ≥50% stenosis and compared to the reference standard. Data were analysed on a segment-by-segment basis and also in 'whole patient' terms. Results: A total of 412/450 segments from 35 patients were suitable for analysis. The overall accuracy of MDCTA for detection of segments with ≥50% stenosis was high, with a sensitivity of 81.3%, specificity 95.0%, positive predictive value (PPV) 57.8%, and negative predictive value (NPV) 98.4%. On a 'whole-patient' basis, 100% (19/19) of patients with significant coronary disease were correctly identified and there were no false-negatives. Excluding patients with CAC >1000 from the analysis improved the accuracy of MDCTA to: sensitivity 90%, specificity 98.1%, PPV 60%, NPV 99.7%. Conclusion: Non-invasive 16-detector row MDCTA accurately excludes significant coronary disease in patients with severe aortic stenosis undergoing evaluation before aortic valve replacement and in whom ICA can therefore be avoided. Its segment-by-segment accuracy is improved further if CAC > 1000 is used as a gatekeeper to MDCTA
Directory of Open Access Journals (Sweden)
Parwinder Kaur
2017-09-01
Full Text Available Mitigating methane production by ruminants is a significant challenge to global livestock production. This research offers a new paradigm to reduce methane emissions from ruminants by breeding climate-clever clovers. We demonstrate wide genetic diversity for the trait methanogenic potential in Australia’s key pasture legume, subterranean clover (Trifolium subterraneum L.. In a bi-parental population the broadsense heritability in methanogenic potential was moderate (H2 = 0.4 and allelic variation in a region of Chr 8 accounted for 7.8% of phenotypic variation. In a genome-wide association study we identified four loci controlling methanogenic potential assessed by an in vitro fermentation system. Significantly, the discovery of a single nucleotide polymorphism (SNP on Chr 5 in a defined haplotype block with an upstream putative candidate gene from a plant peroxidase-like superfamily (TSub_g18548 and a downstream lectin receptor protein kinase (TSub_g18549 provides valuable candidates for an assay for this complex trait. In this way haplotype variation can be tracked to breed pastures with reduced methanogenic potential. Of the quantitative trait loci candidates, the DNA-damage-repair/toleration DRT100-like protein (TSub_g26967, linked to avoid the severity of DNA damage induced by secondary metabolites, is considered central to enteric methane production, as are disease resistance (TSub_g26971, TSub_g26972, and TSub_g18549 and ribonuclease proteins (TSub_g26974, TSub_g26975. These proteins are good pointers to elucidate the genetic basis of in vitro microbial fermentability and enteric methanogenic potential in subterranean clover. The genes identified allow the design of a suite of markers for marker-assisted selection to reduce rumen methane emission in selected pasture legumes. We demonstrate the feasibility of a plant breeding approach without compromising animal productivity to mitigate enteric methane emissions, which is one of the most
Effect of toasting field beans and of grass-clover
DEFF Research Database (Denmark)
Mogensen, Lisbeth; Vestergaard, Jannie Steensig; Fretté, Xavier
2010-01-01
The effect of toasting field beans and of grass-clover: maize silage ratio on milk production, milk composition and the sensory quality of the milk was investigated in a 2 2 factorial experiment. Toasting of field beans resulted in lower milk contents of both fat (44.2 versus 46.1 g/kg, P = 0.......02) and protein (33.5 versus 34.2 g/kg, P = 0.008), whereas milk production, urea and somatic cell contents were unaffected compared with the untreated field beans. Increasing the proportion of maize silage (from 9 to 21% of DM) in the ration decreased the content of urea in milk (P = 0.002), whereas milk......-β-carotene (P = 0.04) and β-carotene (P = 0.05). Toasting of field beans compared with untreated field beans did not affect the milk content of carotenoids and had only small effects on fatty acid composition. Regarding the sensory quality, the four treatments resulted in milk being characterized...
CdTe and CdZnTe gamma ray detectors for medical and industrial imaging systems
International Nuclear Information System (INIS)
Eisen, Y.; Shor, A.; Mardor, I.
1999-01-01
CdTe and CdZnTe X-ray and gamma ray detectors in the form of single elements or as segmented monolithic detectors have been shown to be useful in medical and industrial imaging systems. These detectors possess inherently better energy resolution than scintillators coupled to either photodiodes or photomultipliers, and together with application specific integrated circuits they lead to compact imaging systems of enhanced spatial resolution and better contrast resolution. Photopeak efficiencies of these detectors is greatly affected by a relatively low hole mobility-lifetime product. Utilizing these detectors as highly efficient good spectrometers, demands use of techniques to improve their charge collection properties, i.e., correct for variations in charge losses at different depths of interaction in the detector. The corrections for the large hole trapping are made either by applying electronic techniques or by fabricating detector or electrical contacts configurations which differ from the commonly used planar detectors. The following review paper is divided into three parts: The first part discusses detector contact configurations for enhancing photopeak efficiencies and the single carrier collection approach which leads to improved energy resolutions and photopeak efficiencies at high gamma ray energies. The second part demonstrates excellent spectroscopic results using thick CdZnTe segmented monolithic pad and strip detectors showing energy resolutions less than 2% FWHM at 356 keV gamma rays. The third part discusses advantages and disadvantages of CdTe and CdZnTe detectors in imaging systems and describes new developments for medical diagnostics imaging systems
J.Q. Burkhart; J.R. Rentch; T.M. Schuler
2013-01-01
Identifying habitat preferences of species of concern is fundamental to the practice of conservation, but disturbances and other environmental processes can substantially affect suitability. Trifolium stoloniferum, or running buffalo clover, is a federally endangered plant species that occurs on the Fernow Experimental Forest in West Virginia....
DEFF Research Database (Denmark)
Hauggaard-Nielsen, Henrik; Johansen, Anders; Carter, Mette Sustmann
2013-01-01
A cropping system was designed to fulfill the increasing demand for biomass for food and energy without decreasing long term soil fertility. A field experiment was carried out including alternating strips of annual maize (Zea mays L.) and perennial ryegrass (Lolium perenne L.) – clover (Trifolium...
Heavy Ion Physics at the LHC with the ATLAS Detector
Steinberg, P.
2007-01-01
The ATLAS detector at CERN will provide a high-resolution longitudinally-segmented calorimeter and precision tracking for the upcoming study of heavy ion collisions at the LHC (sqrt{s_{NN}=5520 GeV). The calorimeter covers |eta|<5 with both electromagnetic and hadronic sections, while the inner detector spectrometer covers |eta|<2.5. ATLAS will study a full range of observables necessary to characterize the hot and dense matter formed at the LHC. Global measurements (particle multiplicities, collective flow) will provide access into its thermodynamic and hydrodynamic properties. Measuring complete jets out to 100's of GeV will allow detailed studies of energy loss and its effect on jets. Quarkonia will provide a handle on deconfinement mechanisms. ATLAS will also study the structure of the nucleon and nucleus using forward physics probes and ultraperipheral collisions, both enabled by segmented Zero Degree Calorimeters.
Heavy ion physics at the LHC with the ATLAS detector
International Nuclear Information System (INIS)
Steinberg, P
2007-01-01
The ATLAS detector at CERN will provide a high-resolution longitudinally segmented calorimeter and precision tracking for the upcoming study of heavy ion collisions at the LHC (√s NN = 5520 GeV). The calorimeter covers |η| < 5 with both electromagnetic and hadronic sections, while the inner detector spectrometer covers |η| < 2.5. ATLAS will study a full range of observables necessary to characterize the hot and dense matter formed at the LHC. Global measurements (particle multiplicities, collective flow) will provide access into its thermodynamic and hydrodynamic properties. Measuring complete jets out to 100's of GeV will allow detailed studies of energy loss and its effect on jets. Quarkonia will provide a handle on deconfinement mechanisms. ATLAS will also study the structure of the nucleon and nucleus using forward physics probes and ultraperipheral collisions, both enabled by segmented zero degree calorimeters
Energy Technology Data Exchange (ETDEWEB)
Rosse, B
2006-07-15
This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A {approx} 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr{sup 76} radioactive beam (T1/2 = 14.8 h). {gamma}-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first {gamma} transition was observed in the very exotic odd-odd Pm{sup 130} nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)
γ-spectroscopy and radioactive beams: search for highly deformed exotic nuclei
International Nuclear Information System (INIS)
Rosse, B.
2006-07-01
This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A ∼ 130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient Kr 76 radioactive beam (T1/2 = 14.8 h). γ-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first γ transition was observed in the very exotic odd-odd Pm 130 nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)
γ-spectroscopy and radioactive beams: search for highly deformed exotic nuclei
International Nuclear Information System (INIS)
Rosse, Bertrand
2006-01-01
This work is devoted to the search for highly deformed nuclei under extreme conditions of isospin, located near the proton drip-line, around A∼130. The experiment was performed at GANIL (Caen) with the SPIRAL radioactive beam facility. The nuclei of interest were produced by fusion-evaporation reactions induced by the neutron deficient 76 Kr radioactive beam (T 1/2 = 14.8 h). γ-rays were detected by the EXOGAM array, composed of 11 segmented germanium clover detectors, for which a new segment calibration method has been developed. To extract fusion-evaporation events of a overwhelming background due to the radioactivity of the beam, the EXOGAM array was coupled with the light charged particle detector DIAMANT and the high acceptance VAMOS spectrometer. The latter was used for the first time to detect fusion-evaporation residues. The detailed data analysis allowed us to demonstrate that the EXOGAM + DIAMANT + VAMOS coupling is operational and essential to investigate the structure of these nuclei. Furthermore, the first γ transition was observed in the very exotic odd-odd 130 Pm nucleus. The results have been interpreted with static and dynamic self-consistent microscopic calculations in collaboration with the Theoretical Physicists of the IPN Lyon. (author)
The BaBar LST Detector High Voltage System: Design And Implementation
International Nuclear Information System (INIS)
Benelli, G.; Honscheid, K.; Lewis, E.A.; Regensburger, J.J.; Smith, D.S.; Ohio State U.
2006-01-01
In 2004, the first two sextants of the new Limited Streamer Tube (LST) detector were installed in the BABAR experiment to replace the ageing Resistive Plate Chambers (RPCs) as active detectors for the BABAR Instrumented Flux Return (IFR) muon system. Each streamer tube of the new detector consists of 8 cells. The cell walls are coated with graphite paint and a 100 (micro)m wire forms the anode. These wires are coupled in pairs inside the tubes resulting in 4 independent two-cell segments per LST. High voltage (HV) is applied to the 4 segments through a custom connector that also provides the decoupling capacitor to pick up the detector signals from the anode wires. The BABAR LST detector is operated at 5.5 kV. The high voltage system for the LST detector was designed and built at The Ohio State University (OSU HVPS). Each of the 25 supplies built for BaBar provides 80 output channels with individual current monitoring and overcurrent protection. For each group of 20 channels the HV can be adjusted between 0 and 6 kV. A 4-fold fan-out is integrated in the power supplies to provide a total of 320 outputs. The power supplies are controlled through built-in CANbus and Ethernet (TCP/IP) interfaces. In this presentation we will discuss the design and novel features of the OSU HVPS system and its integration into the BABAR EPICS detector control framework. Experience with the supplies operation during the LST extensive quality control program and their performance during the initial data taking period will be discussed
Segmented-spectrum detection mechanism for medical x-ray in CdTe
Shi, Zaifeng; Meng, Qingzhen; Cao, Qingjie; Yao, Suying
2016-01-01
This paper presents a segmented X-ray spectrum detection method based on a layered X-ray detector in Cadmium Telluride (CdTe) substrate. We describe the three-dimensional structure of proposed detector pixel and investigate the matched spectrum-resolving method. Polychromatic X-ray beam enter the CdTe substrate edge on and will be absorbed completely in different thickness varying with photon energy. Discrete potential wells are formed under external controlling voltage to collect the photo-electrons generated in different layers, and segmented X-ray spectrum can be deduced from the quantity of photo-electrons. In this work, we verify the feasibility of the segmented-spectrum detection mechanism by simulating the absorption of monochromatic X-ray in a CdTe substrate. Experiments in simulation show that the number of photo-electrons grow exponentially with the increase of incident thickness, and photons with different energy will be absorbed in various thickness. The charges generated in different layers are collected into adjacent potential wells, and collection efficiency is estimated to be about 87% for different incident intensity under the 40000V/cm electric field. Errors caused by charge sharing between neighboring layers are also analyzed, and it can be considered negligible by setting appropriate size of electrodes.
International Nuclear Information System (INIS)
Novikov, Yu.F.; Lobach, G.A.; Buzenko, T.A.; Zaretskaya, T.P.
1993-01-01
The basic regularities of radionuclide distribution between the obtained products have been studied using the fractionation of lupine and clover phytomass as an example. The content of radionuclides in protein concentrates has been shown to be strongly related to the crop species. A scheme and a regime of the fractionation of leaf-stem lupine biomass contaminated with cesium radioisotopes and strontium-90 which ensured the minimizing of their residual content in protein-vitaminic and protein concentrates have been selected with due accout of experimental data
Automatic segmentation of mandible in panoramic x-ray.
Abdi, Amir Hossein; Kasaei, Shohreh; Mehdizadeh, Mojdeh
2015-10-01
As the panoramic x-ray is the most common extraoral radiography in dentistry, segmentation of its anatomical structures facilitates diagnosis and registration of dental records. This study presents a fast and accurate method for automatic segmentation of mandible in panoramic x-rays. In the proposed four-step algorithm, a superior border is extracted through horizontal integral projections. A modified Canny edge detector accompanied by morphological operators extracts the inferior border of the mandible body. The exterior borders of ramuses are extracted through a contour tracing method based on the average model of mandible. The best-matched template is fetched from the atlas of mandibles to complete the contour of left and right processes. The algorithm was tested on a set of 95 panoramic x-rays. Evaluating the results against manual segmentations of three expert dentists showed that the method is robust. It achieved an average performance of [Formula: see text] in Dice similarity, specificity, and sensitivity.
Interesting detector shapes for 3rd generation CT
Energy Technology Data Exchange (ETDEWEB)
Kachelriess, Marc [Erlangen-Nuernberg Univ., Erlangen (Germany). Inst. of Medical Physics (IMP)
2011-07-01
Third generation CT scanners typically comprise detectors which are flat or whose shape is the segment of a cylinder or a sphere that is focussed onto the focal spot of the X-ray source. There appear to be two design criteria that favor this choice of detector shape. One is the possibility of performing fan-beam and cone-beam filtered backprojection in the native geometry (without rebinning) and the other criterium is to enable the use of focussed anti scatter grids. It is less known, however, that other detector shapes may also have these properties. While these designs have been evaluated for 2D CT from a rather theoretical standpoint more than one decade ago we revisit and generalize these considerations, extend them to 3D circular, sequential and spiral cone-beam CT and propose an optimal design in terms of detector costs. (orig.)
International Nuclear Information System (INIS)
Asih Kurniawati
2004-01-01
(Trifolium pratense cv. Sabatron). Red clover silage supplemented with different level of carbohydrates has been examined using the in-vitro gas production technique. Cumulative gas production, hydro.gen sulfite production, and ammonia was followed and used as indicators of microbial growth rate and extent of protein degradation. Microbial nitrogen production, VFA, and efficiency microbial production was used as indicator of nitrogen use efficiency. 15 N was used as a microbial marker to estimate the amount of nitrogen incorporation into microbial protein. Supplementation of Red clover with increasing 5 levels; 0 g; 0.625 g; 0.15 g; 0.225 g and 0.3 g of maize starch led to graded increase in microbial growth and protein degradation. This was reflected in the increasing gas production and the accumulation of hydrogen sulfite. Diurnal change in ammonia production reflected the microbial utilization of ammonia for protein synthesis. Protein microbe (P<0.001) as VFA (P<0.001) increased due to carbohydrate addition as well as utilization of nitrogen (P<0.001). There was also the efficiency of nitrogen utilization which increased significantly. This result suggested that energy supply can increased efficiency of nitrogen use in the rumen and may reduce nitrogen losses into the environment. (author)
A many particle-tracking detector with drift planes and segmented cathode readout
International Nuclear Information System (INIS)
Fischer, J.; Lissauer, D.; Ludlam, T.; Makowiecki, D.; O'Brien, E.; Radeka, V.; Rescia, S.; Rogers, L.; Smith, G.C.; Stephani, D.; Yu, B.; Greene, S.V.; Hemmick, T.K.; Mitchell, J.T.; Shivakumar, B.
1990-01-01
We describe the design and performance of a detector system for tracking charged particles in an environment of high track density and rates up to 1 MHz. The system operates in the forward spectrometer of the BNL Heavy Ion experiment E814 and uses principles of general interest in high rate, high multiplicity applications such as at RHIC or SSC. We require our system to perform over a large dynamic range, detecting singly charged particles as well as fully ionized relativistic 28 Si. Results on gas gain saturation, δ-ray suppression, and overall detector performance in the presence of a 14.6 GeV/nucleon 28 Si beam and a 14 GeV proton beam are presented. 6 refs., 9 figs
Forage mass and the nutritive value of pastures mixed with forage peanut and red clover
Directory of Open Access Journals (Sweden)
Ricardo Lima de Azevedo Junior
2012-04-01
Full Text Available The objective of this research was to estimate three pasture-based systems mixed with elephantgrass + spontaneous growth species, annual ryegrass, for pasture-based system 1; elephantgrass + spontaneous growth species + forage peanut, for pasture-based system 2; and elephantgrass + spontaneous growth species + annual ryegrass + red clover, for pasture-based system 3. Elephantgrass was planted in rows 4 m apart from each other. During the cool-season, annual ryegrass was sown in the alleys between the rows of elephantgrass; forage peanut and red clover were sown in the alleys between the elephantgrass according to the respective treatment. The experimental design was totally randomized in the three treatments (pasture-based systems, two replicates (paddocks in completely split-plot time (grazing cycles. Holstein cows receiving 5.5 kg-daily complementary concentrate feed were used in the evaluation. Pre-grazing forage mass, botanical composition and stocking rate were evaluated. Samples of simulated grazing were collected to analyze organic matter (OM, neutral detergent fiber (NDF, crude protein (CP and organic matter in situ digestibility (OMISD. Nine grazing cycles were performed during the experimental period (341 days. The average dry matter values for pre-grazing and stocking rate were 3.34; 3.46; 3.79 t/ha, and 3.28; 3.34; 3.60 AU/ha for each respective pasture-based system. Similar results were observed between the pasture-based systems for OM, NDF, CP and OMISD. Considering forage mass, stocking rate and nutritive value, the pasture-based system intercropped with forage legumes presented better performance.
BFROST: binary features from robust orientation segment tests accelerated on the GPU
CSIR Research Space (South Africa)
Cronje, J
2011-11-01
Full Text Available purpose parallel algo- rithms. The CUDA (Compute Unified Device Architecture) [1] framework from NVidia provides a programmable interface for GPUs. FAST (Features from Accelerated Segment Tests) [2], [3] is one of the fastest and most reliable corner... runs. Our detector detects slightly more keypoints because the decision tree of FAST does not perform a complete segment test. Timing comparisons were performed on a NVidia GeForce GTX 460 for our GPU implementation and on a Intel Core i7 2.67 GHz...
A neural method for determining electromagnetic shower positions in laterally segmented calorimeters
International Nuclear Information System (INIS)
Roy, A.; Ray, A.; Mitra, T.; Roy, A.
1995-01-01
A method based on a neural network technique is proposed to calculate the coordinates of an incident photon striking a laterally segmented calorimeter and depositing shower energies in different segments. The technique uses a multilayer perceptron trained by back-propagation implemented through standard gradient descent followed by conjugate gradient algorithms and has been demonstrated with GEANT simulations of a BAF2 detector array. The position resolution results obtained by using this method are found to be substantially better than the first moment method with logarithmic weighting. (orig.)
Development of Trigger and Readout Electronics for the ATLAS New Small Wheel Detector Upgrade
Antrim, Daniel Joseph; The ATLAS collaboration
2017-01-01
The present small wheel muon detector at ATLAS will be replaced with a New Small Wheel (NSW) detector to handle the increase in data rates and harsh radiation environment expected at the LHC. Resistive Micromegas and small-strip Thin Gap Chambers will be used to provide both trigger and tracking primitives. Muon segments found at NSW will be combined with the segments found at the Big Wheel to determine the muon transverse momentum at the first-level trigger. A new trigger and readout system is developed for the NSW detector. The new system has about 2.4 million trigger and readout channels and about 8,000 frontend boards. The large number of input channels, short time available to prepare and transmit data, harsh radiation environment, and low power consumption all impose great challenges on the design. We will discuss the overall electronics design and studies with various ASIC and board prototypes.
Computer-aided design and construction of an antineutrino detector
International Nuclear Information System (INIS)
Stutz, A.
1989-01-01
The Bugey group is setting-up a new detector for another neutrino oscillation experiment. This thesis reports on the different steps concerning its realisation. Light yield, light transmission and pulse shape discrimination properties of NE 320 a new liquid scintillator loaded with 0.15% of Lithium 6 allow to realise a large volume detector (3 x 600 l) with an order of magnitude increase in sensitivity. The benefit of the neutron capture on Lithium 6 has been conserved owing to the segmentation of the whole detector volume in 98 cells and to energy resolution and pulse shape discrimination properties of the liquid. The efficiency is expected to be 0.5 and the essential component of the background is the natural activity of the scintillator. This makes this detector the most performant for neutrino oscillation experiment at reactor [fr
Flat detectors and their clinical applications
International Nuclear Information System (INIS)
Spahn, Martin
2005-01-01
Diagnostic and interventional flat detector X-ray systems are penetrating the market in all application segments. First introduced in radiography and mammography, they have conquered cardiac and general angiography and are getting increasing attention in fluoroscopy. Two flat detector technologies prevail. The dominating method is based on an indirect X-ray conversion process, using cesium iodide scintillators. It offers considerable advantages in radiography, angiography and fluoroscopy. The other method employs a direct converter such as selenium which is particularly suitable for mammography. Both flat detector technologies are based on amorphous silicon active pixel matrices. Flat detectors facilitate the clinical workflow in radiographic rooms, foster improved image quality and provide the potential to reduce dose. This added value is based on their large dynamic range, their high sensitivity to X-rays and the instant availability of the image. Advanced image processing is instrumental in these improvements and expand the range of conventional diagnostic methods. In angiography and fluoroscopy the transition from image intensifiers to flat detectors is facilitated by ample advantages they offer, such as distortion-free images, excellent coarse contrast, large dynamic range and high X-ray sensitivity. These characteristics and their compatibility with strong magnetic fields are the basis for improved diagnostic methods and innovative interventional applications. (orig.)
A new detector array for charged particle spectroscopy
Cowin, R L; Chappell, S P G; Clarke, N M; Freer, M; Fulton, B R; Cunningham, R A; Curtis, N; Dillon, G; Lilley, J; Jones, C D; Lee, P; Rae, W D M
1999-01-01
A compact and highly segmented detector array consisting of 44 gas-silicon-caesium iodide, position sensitive, particle identification detector telescopes and up to 10 position-sensitive, silicon strip detectors has been constructed for the study of light-ion-heavy-ion reactions including cluster break-up in the energy range 5-15 MeV/nucleon. The detectors are housed in a purpose built vacuum chamber. The telescopes are placed in fixed positions, covering the forward hemisphere from 3 to 30 deg. in the laboratory with the target placed at 535 mm from the front of the telescopes or 6-52 deg. with the target placed at 215 mm. The strip detectors are placed in any of 30 fixed positions in the forward hemisphere. For 85 MeV sup 1 sup 2 C ions the telescope energy resolution (gas plus silicon) is 345 keV with an angular resolution of 0.03 deg. . Using the gas-silicon section ions with Z up to 21 can be identified. For ions that pass through the silicon isotopic identification is achieved using the silicon-CsI comb...
Biochanin A (BCA) is an isoflavone produced by red clover (Trifloium pratense L.) that can inhibit hyper-ammonia producing bacteria (HAB) to reduce deamination in the rumen and increase the feed amino acids available for gastric digestion. An in vitro experiment was conducted to evaluate the effect...
Learning to Segment Human by Watching YouTube.
Liang, Xiaodan; Wei, Yunchao; Chen, Yunpeng; Shen, Xiaohui; Yang, Jianchao; Lin, Liang; Yan, Shuicheng
2016-08-05
An intuition on human segmentation is that when a human is moving in a video, the video-context (e.g., appearance and motion clues) may potentially infer reasonable mask information for the whole human body. Inspired by this, based on popular deep convolutional neural networks (CNN), we explore a very-weakly supervised learning framework for human segmentation task, where only an imperfect human detector is available along with massive weakly-labeled YouTube videos. In our solution, the video-context guided human mask inference and CNN based segmentation network learning iterate to mutually enhance each other until no further improvement gains. In the first step, each video is decomposed into supervoxels by the unsupervised video segmentation. The superpixels within the supervoxels are then classified as human or non-human by graph optimization with unary energies from the imperfect human detection results and the predicted confidence maps by the CNN trained in the previous iteration. In the second step, the video-context derived human masks are used as direct labels to train CNN. Extensive experiments on the challenging PASCAL VOC 2012 semantic segmentation benchmark demonstrate that the proposed framework has already achieved superior results than all previous weakly-supervised methods with object class or bounding box annotations. In addition, by augmenting with the annotated masks from PASCAL VOC 2012, our method reaches a new stateof- the-art performance on the human segmentation task.
Studies on MCM-D pixel-detector-modules
Flick, T; Gerlach, P; Grah, C; Mättig, P; Rohe, T
2003-01-01
In the context of the development of the ATLAS-pixel-detector, a technology for building up the high density interconnects has been studied, the MCM-D (multichip module deposited) technology. Results of building up first assemblies have been reported. MCM-D technology allows to build up assemblies with uniformly segmented sensors. Especially the use of 'equal-sized(-bricked)' sensor geometry has been studied.
A large-acceptance Bragg curve spectrometer with a longitudinal electric field and a segmented anode
International Nuclear Information System (INIS)
Farrar, K.A.; Hasan, A.T.; Prosser, F.W.; Sanders, S.J.; Henderson, D.J.
1994-01-01
A large-acceptance Bragg curve spectrometer with a longitudinal electron collection field and a segmented anode has been constructed and tested. The effects on the charge resolution of the entrance angle and entrance position of the incident particle have been studied. Simulations have been done in order to isolate the contribution to the overall detector performance of the signal-shaping electronics from that of the intrinsic design of the detector. ((orig.))
Monitoring of absolute mirror alignment at COMPASS RICH-1 detector
Energy Technology Data Exchange (ETDEWEB)
Alexeev, M. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); INFN, Sezione di Trieste and University of Bari, Bari (Italy); Birsa, R. [INFN, Sezione di Trieste, Trieste (Italy); Bradamante, F.; Bressan, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Chiosso, M. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Ciliberti, P. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Dalla Torre, S. [INFN, Sezione di Trieste, Trieste (Italy); Denisov, O. [INFN, Sezione di Torino, Torino (Italy); Duic, V. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Ferrero, A. [INFN, Sezione di Torino and University of Torino, Torino (Italy); Finger, M.; Finger, M. [Charles University, Prague (Czech Republic); JINR, Dubna (Russian Federation); Gayde, J.Ch. [CERN, European Organization for Nuclear Research, Geneva (Switzerland); Giorgi, M. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Gobbo, B.; Levorato, S. [INFN, Sezione di Trieste, Trieste (Italy); Maggiora, A. [INFN, Sezione di Torino, Torino (Italy); Martin, A. [INFN, Sezione di Trieste and University of Trieste, Trieste (Italy); Menon, G. [INFN, Sezione di Trieste, Trieste (Italy); Panzieri, D. [INFN, Sezione di Torino and University of East Piemonte, Alessandria (Italy); and others
2014-12-01
The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM) photogrammetry-based method has been implemented to measure the alignment of individual mirrors which can be characterized by the center of curvature. The mirror wall reflects a regular grid of retroreflective strips placed inside the detector vessel. Then, the position of each mirror is determined from the image of the grid reflection. The images are collected by four cameras. Any small mirror misalignment results in changes of the grid lines’ positions in the image. The accuracy limits of the CLAM method were checked by laser interferometry and are below 0.1 mrad.
Hart, E H; Onime, L A; Davies, T E; Morphew, R M; Kingston-Smith, A H
2016-06-01
Increasing the rumen-stable protein content of feed would lead to improved nitrogen utilisation in cattle, and less nitrogenous waste. Red clover (Trifolium pratense L.) is a high protein ruminant feed containing high polyphenol oxidase (PPO) activity. PPO mediated protein-quinone binding has been linked to protecting plant proteins from proteolysis. To explore the mechanism underlying the effect of PPO on protein protection in fresh forage feeds, proteomic components of feed down-boli produced from wild-type red clover and a low PPO mutant, at point of ingestion and after 4h in vitro incubation with rumen inoculum were analysed. Significant differences in proteomic profiles between wild-type and mutant red clover were determined after 4h incubation, with over 50% less spots in mutant than wild-type proteomes, indicating decreased proteolysis in the latter. Protein identifications revealed preferentially retained proteins localised within the chloroplast, suggesting that PPO mediated protection in the wild-type operates due to the proximity of target proteins to the enzyme and substrates, either diffusing into this compartment from the vacuole or are present in the chloroplast. This increased understanding of protein targets of PPO indicates that wider exploitation of the trait could contribute to increased protein use efficiency in grazing cattle. One of the main challenges for sustainable livestock farming is improving capture of dietary nitrogen by ruminants. Typically up to 70% of ingested protein-N is excreted representing a loss of productivity potential and a serious environmental problem in terms of nitrogenous pollution of lands and water. Identification of key characteristics of rumen-protected protein will deliver target traits for selection in forage breeding programmes. The chloroplastic enzyme PPO catalyzes the oxidation of phenols to quinones, which react with protein. Little is currently known about the intracellular protein targets of the products
Charge collection in silicon strip detectors
International Nuclear Information System (INIS)
Kraner, H.W.; Beuttenmuller, R.; Ludlam, T.; Hanson, A.L.; Jones, K.W.; Radeka, V.; Heijne, E.H.M.
1982-11-01
The use of position sensitive silicon detectors as very high resolution tracking devices in high energy physics experiments has been a subject of intense development over the past few years. Typical applications call for the detection of minimum ionizing particles with position measurement accuracy of 10 μm in each detector plane. The most straightforward detector geometry is that in which one of the collecting electrodes is subdivided into closely spaced strips, giving a high degree of segmentation in one coordinate. Each strip may be read out as a separate detection element, or, alternatively, resistive and/or capacitive coupling between adjacent strips may be exploited to interpolate the position via charge division measrurements. With readout techniques that couple several strips, the numer of readout channels can, in principle, be reduced by large factors without sacrificing the intrinsic position accuracy. The testing of individual strip properties and charge division between strips has been carried out with minimum ionizing particles or beams for the most part except in one case which used alphs particless scans. This paper describes the use of a highly collimated MeV proton beam for studies of the position sensing properties of representative one dimensional strip detectors
Nitrous oxide emissions from clover in the Mediterranean environment
Directory of Open Access Journals (Sweden)
Iride Volpi
2016-06-01
Full Text Available Introducing nitrogen N2-fixing crops into cereal-based crop rotations reduces N-fertiliser use and may mitigate soil emissions of nitrous oxide (N2O. However, the effect of the cultivation of N2-fixing crops on N2O emissions is still not well understood. N2O from N2-fixing crops can be emitted in two ways: during biological N2 fixation itself and when legume residues are returned to the soil. A field trial was carried out on clover (Trifolium squarrosum Savi to test the role of leguminous crops on N2O emissions in the Mediterranean environment. Monitoring was performed from December 2013 to September 2014. Cumulated N-N2O fluxes were calculated for the growing season (Phase 1 and the post-harvest period (Phase 2 in order to assess the importance of each phase. Our results did not show statistically significant differences between the two phases in term of contribution to the total cumulative N-N2O emissions, in fact Phase 1 and Phase 2 accounted respectively for 43 and 57% of the total.
Development of Trigger and Readout Electronics for the ATLAS New Small Wheel Detector Upgrade
Guan, Liang; The ATLAS collaboration
2017-01-01
The present small wheel muon detector at ATLAS will be replaced with a New Small Wheel (NSW) detector to handle the increase in data rates and harsh radiation environment expected at the LHC. Resistive Micromegas and small strip Thin Gap Chambers will be used to provide both trigger and tracking primitives. Muon segments found at NSW will be combined with the segments found at the Big Wheel to determine the muon transverse momentum at the first-level trigger. A new trigger and readout system is developed for the NSW detector. The new system has about 2.4 million trigger and readout channels and about 8,000 Front-End boards. The large number of input channels, short time available to prepare and transmit data, harsh radiation environment, and low power consumption all impose great challenges on the design. We will discuss the overall electronics design and studies with various ASICs and high-speed circuit board prototypes.
Measurement of β-decay end point energy with planar HPGe detector
Bhattacharjee, T.; Pandit, Deepak; Das, S. K.; Chowdhury, A.; Das, P.; Banerjee, D.; Saha, A.; Mukhopadhyay, S.; Pal, S.; Banerjee, S. R.
2014-12-01
The β - γ coincidence measurement has been performed with a segmented planar Hyper-Pure Germanium (HPGe) detector and a single coaxial HPGe detector to determine the end point energies of nuclear β-decays. The experimental end point energies have been determined for some of the known β-decays in 106Rh →106Pd. The end point energies corresponding to three weak branches in 106Rh →106Pd decay have been measured for the first time. The γ ray and β particle responses for the planar HPGe detector were simulated using the Monte Carlo based code GEANT3. The experimentally obtained β spectra were successfully reproduced with the simulation.
Segmented gamma scanning method for measuring holdup in the spherical container
International Nuclear Information System (INIS)
Deng Jingshan; Li Ze; Gan Lin; Lu Wenguang; Dong Mingli
2007-01-01
Some special nuclear material (SNM) is inevitably deposited in the facilities (mixer, reactor) of nuclear material process line. Exactly knowing the quantity of nuclear material holdup is very important for nuclear material accountability and critical safety. This paper presents segmented gamma scanning method for SNM holdup measurement of spherical container, at the left, right and back of which other equipments exist so that the detectors can be put at the only front of container for measurement. The nuclear material deposited in the spherical container can be looked as spherical shell source, which is divided into many layers. The detectors scanning spherical shell source are moved layer by layer from the top to the bottom to obtain projection data, with which deposited material distribution can be reconstructed by using Least Square (LS) method or Maximum Likelihood (ML) method. With these methods accurate total holdup can be obtained by summing up all the segmental values reconstructed. In this paper this measurement method for holdup in the spherical container was verified with Monte-Carlo simulation calculation and experiment. (authors)
Genetic variability of isoflavones in the USDA red clover core collection
Directory of Open Access Journals (Sweden)
Graziele P. Ramos
2012-11-01
Full Text Available Red clover is one of the most utilized forage in agriculture and contains many of the isoflavones known for their human health benefits. The objectives of this study were: i to quantify, using HPLC analysis, isoflavones in 77 accessions from the USDA core collection and a Brazilian line; ii to verify possible relationships depending on their origin, improvement status or maturity type and; iii to verify the seasonal variation. The isoflavone mean contents were 29.27 µg g-1 of dry material for daidzein, 163.69 µg g-1 for genistein, 11353.29 µg g-1 for formononetin and 6568.8 µg g-1 for biochanin A. Clustering was mainly influenced by the total amount of isoflavones and partially due to maturity type, improvement status and geographic origin. The seasonal evaluation demonstrated an increase of concentration during winter, and decrease during spring. These results highlighted accessions that can be used to develop new varieties with low or high isoflavones concentration.
Response of irradiated Egyptian clover (Trifolium alexandrinum L.) to water stress
International Nuclear Information System (INIS)
Hamideldin, N; Hussein, O.S
2009-01-01
Egyptian clover (Trifolium alexandrinum L.) is one of the main leguminous forage crops in Egypt. Gamma rays represent one of the important physical activators for growth and productivity. The seed were irradiated using three doses of gamma radiation (100,200 and 300 Gy) and two levels of irrigation (10 and 20 days) after germination. Gamma radiation treatments stimulated growth criteria in normal irrigation treatment, while drought irrigation treatment stunted these criteria. The most significant dose was 100 Gy, which stimulated growth criteria, chlorophylls a , b, total chlorophyll and carotenoids in both irrigation treatments used and growth hormones under drought condition. Drought stress and gamma irradiation increase amino acid content and caused change in band concentration of esterase and peroxidase isozyme .Also, 13 protein bands appeared only in treated plant with 100 Gy under drought condition. It could be concluded that the low dose (100 Gy) of gamma irradiation release the effect of drought stress.
The Anti-Coincidence Detector for the GLAST Large Area Telescope
Energy Technology Data Exchange (ETDEWEB)
Moiseev, A.A.; Hartman, R.C.; Ormes, J.F.; Thompson, D.J.; Amato, M.J.; Johnson, T.E.; Segal, K.N.; Sheppard, D.A.
2007-03-23
This paper describes the design, fabrication and testing of the Anti-Coincidence Detector (ACD) for the Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT). The ACD is LAT's first-level defense against the charged cosmic ray background that outnumbers the gamma rays by 3-5 orders of magnitude. The ACD covers the top and 4 sides of the LAT tracking detector, requiring a total active area of {approx}8.3 square meters. The ACD detector utilizes plastic scintillator tiles with wave-length shifting fiber readout. In order to suppress self-veto by shower particles at high gamma-ray energies, the ACD is segmented into 89 tiles of different sizes. The overall ACD efficiency for detection of singly charged relativistic particles entering the tracking detector from the top or sides of the LAT exceeds the required 0.9997.
International Nuclear Information System (INIS)
Abdel-Rehim, Abdou; Kallidonis, Christos; Koutsou, Giannis
2015-11-01
We compute the disconnected quark loops contributions entering the determination of nucleon observables, by using a N f =2 ensemble of twisted mass fermions with a clover term at a pion mass m π =133 MeV. We employ exact deflation and implement all calculations in GPUs, enabling us to achieve large statistics and a good signal.
A new strips tracker for the upgraded ATLAS ITk detector
David, Claire; The ATLAS collaboration
2017-01-01
The inner detector of the present ATLAS detector has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the next-generation tracking detector proposed for the High Luminosity LHC (HL-LHC), the so-called ATLAS Phase-II Upgrade, the particle densities and radiation levels will be higher by as much as a factor of ten. The new detectors must be faster, they need to be more highly segmented, and covering more area. They also need to be more resistant to radiation, and they require much greater power delivery to the front-end systems. At the same time, they cannot introduce excess material which could undermine performance. For those reasons, the inner tracker of the ATLAS detector must be redesigned and rebuilt completely. The design of the ATLAS Upgrade inner tracker (ITk) has already been defined. It consists of several layers of silicon particle detectors. The innermost layers will be composed of silicon pixel sensors, and the outer layers will consist of s...
Detector of reactor antineutrinos with plastic scintillation bars
International Nuclear Information System (INIS)
Georgadze, A.Sh.; Pavlovich, V.M.
2015-01-01
Project of a segmented antineutrino detector is developed with the use of plastic scintillator rectangular bars 10 x 10 x 100 cm, wrapped in Gd foils and assembled to an array of 1 m3 active volume. The scintillation array is sandwiched at both sides by the continuous light guides of 100 x 100 x 10 cm size, from which the scintillation light is spreading simultaneously through continuous light guides between all photomultipliers, forming the specific Light Response Function (LRF), which is character to a certain nuclear event in detector. Analysis of LRF allows one effectively reject background events, providing high efficiency detection of antineutrino capture in the detector. Monte Carlo simulations with the help of MCNP and ZEMAX software show that with the use of selection criteria the neutrino events are well separated from the background
International Nuclear Information System (INIS)
Kim, Yoo Kyung; Shim, Sung Shine; Lim, Soo Mee; Hwang, Ji Young; Kim, Yoon Kyung
2005-01-01
The purpose of this experiment is to investigate the image quality of CT coronary angiography using a 16-slice multi-detector row CT and to determine the optimal image reconstruction window. CT coronary angiography was obtained in 36 nonsymptomatic volunteers using a 16-slice multi-detector row CT (SOMATOM Sensation, Siemens Medical System). The mean heart rates were 70 beats per minute (bpm) or less in 18 persons and more than 70 bpm in 18 persons. Eleven data sets were obtained for each patient (reconstructed at 30%-80% of the cardiac cycle with an increment of 5%). Image quality of the eight coronary segments [left main coronary artery (LM), proximal and middle segments of left anterior descending artery (p-LAD, m-LAN) and left circumflex coronary artery (p-LCx, m-LCx) and proximal, middle and distal segments of right coronary artery (p-RCA, m-RCA, d-RCA)] was assessed. The optimal reconstruction windows in the cardiac cycle for the best image quality were 60-70% for the segments of the LM, LAD, and LC arteries in two groups (bpm 70) and 55-65% (bpm 70) for the segments of the RCA. On the best dataset for each coronary segment, the following diagnostic image quality was achieved in the two groups: LM: 100%, 83%; p-LAD: 100%, 88% m-LAD: 100%, 72%; p-LCx: 100%, 72%; m-LCx: 100%, 72%; p-RCA: 94%, 72%; m-RCA: 61%, 50%; d-RCA: 100%, 80%. The 16 slice multi-detector row CT scan provided visualization of the coronary arteries with high resolution. Especially in the group with a mean heart rate of 70 bpm or less, all the coronary segments except the RCA showed diagnostic image quality. Optimal image quality was achieved with a 60-70% trigger delay for all coronary arterial segments, but the best images of RCA were achieved in the earlier cardiac phase in the patients with a mean heart rate of more than 70 bpm
Flat-panel detectors in x-ray diagnosis
International Nuclear Information System (INIS)
Spahn, M.; Heer, V.; Freytag, R.
2003-01-01
For all application segments X-ray systems with flat-panel detectors increasingly enter the market. In digital radiography, mammography and cardiologic angiography flat-panel detectors are already well established while they are made ready for market introduction in general angiography and fluoroscopy. Two flat-panel detector technologies are available. One technology is based on an indirect conversion process of X-rays while the other one uses a direct conversion method.For radiography and dynamic applications the indirect method provides substantial advantages, while the direct method has some benefits for mammography. In radiography and mammography flat-panel detectors lead to clear improvements with respect to workflow, image quality and dose reduction potentials. These improvements are fostered by the immediate availability of the image, the large dynamic range and the high sensitivity to X-rays. New applications and the use of complex image processing algorithms have the potential to enlarge the present diagnostic range of applications.Up to now, image intensifiers are still the well-established technology for angiography and fluoroscopy. Nevertheless flat-panel detectors begin to enter this field, especially in cardiologic angiography.Characteristics of flat-panel detectors such as the availability of distortion-free images, the excellent contrast resolution, the large dynamic range, the high sensitivity to X-rays and the usability in magnetic fields provide the basis for improved and new diagnostic and interventional methods. (orig.) [de
Ozone and Water Stress: Effects on the Behaviour of Two White Clover Biotypes
Directory of Open Access Journals (Sweden)
Massimo Fagnano
Full Text Available ozone pollution, water stress, stomata conductance, ozone uptake, clover, OTC.Ozone is a strong oxidizing pollutant which derives by alteration of the photolytic NOx cycle and it accumulates in the troposphere spreading in rural areas and therefore determining injuries on natural vegetation and crops. Since its penetration occurs mainly through stomata, all factors which alter plant-atmosphere relations could be able to modify plant response to ozone. Interaction between ozone and water stress in Mediterranean environment was studied on ozone resistant and sensitive biotypes of white clover, which were grown in charcoal filtered and notfiltered Open Top Chambers in factorial combination with different levels of water supply. Measurements of biomass, leaf area and stomatal conductance were made during the growth period. Ozone injuries were estimated as not-filtered/filtered OTC yield ratio; the stomatal flux of ozone was estimated multiplying stomata conductance x diffusivity ratio between ozone and water vapour (0.613 x ozone hourly concentrations. The hourly values of ozone uptake were cumulated throughout the cropping periods of the two years. In the sensitive biotype, water stress reduced yield losses due to ozone from 38% to 22%, as well as yield losses due to water stress were reduced by the presence of ozone from 43% to 29%, while no interaction between ozone and water stress was observed in the resistant biotype. Biomass yield losses of the sensitive biotype were strictly correlated to cumulated ozone uptake (R2 = 0.99, while biomass yield losses of the resistant biotype were not affected by the ozone fluxes variations created by the treatments. Flux based models could better estimate yield losses due to ozone in Mediterranean environments in which other stresses could be contemporary present; therefore, the new European directives might replace the actual thresholds based
Energy Technology Data Exchange (ETDEWEB)
Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics; Perlt, H.; Schiller, A. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division, Dept. of Mathematical Sicences; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2008-06-15
Using plaquette and Symanzik improved gauge action and stout link clover fermions we determine the improvement coefficient c{sub SW} in one-loop lattice perturbation theory from the off-shell quark-quark-gluon three-point function. In addition, we compute the coefficients needed for the most general form of quark field improvement and present the one-loop result for the critical hopping parameter {kappa}{sub c}. We discuss mean field improvement for c{sub SW} and {kappa}{sub c} and the choice of the mean field coupling for the actions we have considered. (orig.)
Proceedings of the symposium on RHIC detector R&D
Energy Technology Data Exchange (ETDEWEB)
Makdisi, Y.; Stevens, A.J. [eds.
1991-12-31
This report contains papers on the following topics: Development of Analog Memories for RHIC Detector Front-end Electronic Systems; Monolithic Circuit Development for RHIC at Oak Ridge National Laboratory; Highly Integrated Electronics for the STAR TPC; Monolithic Readout Circuits for RHIC; New Methods for Trigger Electronics Development; Neurocomputing methods for Pattern Recognition in Nuclear Physics; The Development of a Silicon Multiplicity Detector System; The Vertex Detector for the Lepton/Photon Collaboration; Simulations of Silicon Vertex Tracker for STAR Experiment at RHIC; Calorimeter/Absorber Optimization for a RHIC Dimuon Experiment (RD-10 Project); Applications of the LAHET simulation Code to Relativistic Heavy Ion Detectors; Highly Segmented, High Resolution Time-of-Flight System; Research and Development on a Sub 100 Picosecond Time-of-Flight System Based on Silicon Avalance Diodes; Behavior of TPC`s in a High Particle Flux Environment; Generic R&D on Undoped Cesium Iodide and Lead Fluoride; and A Transition Radiation Detector for RHIC Featuring Accurate Tracking and dE/dx Particle Identification. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.
Low dose radiation damage effects in silicon strip detectors
International Nuclear Information System (INIS)
Wiącek, P.; Dąbrowski, W.
2016-01-01
The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.
Low dose radiation damage effects in silicon strip detectors
Wiącek, P.; Dąbrowski, W.
2016-11-01
The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.
Schils, R.L.M.; Snijders, P.J.M.
2004-01-01
The combined effect of reduced nitrogen ( N ) and phosphorus ( P ) application on the production of grass- only and grass/ clover swards was studied in a five- year cutting experiment on a marine clay soil, established on newly sown swards. Furthermore, changes in soil N, P and carbon ( C ) were
Angular resolution of the gaseous micro-pixel detector Gossip
Bilevych, Y.; Blanco Carballo, V.; van Dijk, M.; Fransen, M.; van der Graaf, H.; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S.; Rogers, M.; Romaniouk, A.; Veenhof, R.
2011-06-01
Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO 2 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.
Angular resolution of the gaseous micro-pixel detector Gossip
Energy Technology Data Exchange (ETDEWEB)
Bilevych, Y.; Blanco Carballo, V.; Dijk, M. van; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S. [Nikhef, P.O. Box 41882, 1009 DB Amsterdam (Netherlands); Rogers, M. [Radboud University, P.O. Box 9102, 6500HC Nijmegen (Netherlands); Romaniouk, A.; Veenhof, R. [CERN, CH-1211, Geneve 23 (Switzerland)
2011-06-15
Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO{sub 2} 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.
Angular resolution of the gaseous micro-pixel detector Gossip
International Nuclear Information System (INIS)
Bilevych, Y.; Blanco Carballo, V.; Dijk, M. van; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S.; Rogers, M.; Romaniouk, A.; Veenhof, R.
2011-01-01
Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO 2 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.
The high voltage system for the novel MPGD-based photon detectors of COMPASS RICH-1
Dalla Torre, S.; Birsa, R.; Bradamante, F.; Bressan, A.; Chatterjee, C.; Ciliberti, P.; Dasgupta, S.; Gobbo, B.; Gregori, M.; Hamar, G.; Levorato, S.; Martin, A.; Menon, G.; Tessarotto, F.; Zhao, Y.
2018-01-01
The architecture of the novel MPGD-based photon detectors of COMPASS RICH-1 consists in a large-size hybrid MPGD multilayer layout combining two layers of Thick-GEMs and a bulk resistive MICROMEGAS. Concerning biasing voltage, the Thick-GEMs are segmented in order to reduce the energy released in case of occasional discharges, while the MICROMEGAS anode is segmented in pads individually biased at positive voltage, while the micromesh is grounded. In total, there are ten different electrode types and more than 20000 electrodes supplied by more than 100 HV channels. Commercial power supply units are used. The original elements of the power supply system are the architecture of the voltage distribution net, the compensation, by voltage adjustment, of the effects of pressure and temperature variation affecting the detector gain and a sophisticated control software, which allows to protect the detectors against errors by the operator, to monitor and log voltages and current at 1 Hz rate and to automatically react ...
Advanced Dispersed Fringe Sensing Algorithm for Coarse Phasing Segmented Mirror Telescopes
Spechler, Joshua A.; Hoppe, Daniel J.; Sigrist, Norbert; Shi, Fang; Seo, Byoung-Joon; Bikkannavar, Siddarayappa A.
2013-01-01
Segment mirror phasing, a critical step of segment mirror alignment, requires the ability to sense and correct the relative pistons between segments from up to a few hundred microns to a fraction of wavelength in order to bring the mirror system to its full diffraction capability. When sampling the aperture of a telescope, using auto-collimating flats (ACFs) is more economical. The performance of a telescope with a segmented primary mirror strongly depends on how well those primary mirror segments can be phased. One such process to phase primary mirror segments in the axial piston direction is dispersed fringe sensing (DFS). DFS technology can be used to co-phase the ACFs. DFS is essentially a signal fitting and processing operation. It is an elegant method of coarse phasing segmented mirrors. DFS performance accuracy is dependent upon careful calibration of the system as well as other factors such as internal optical alignment, system wavefront errors, and detector quality. Novel improvements to the algorithm have led to substantial enhancements in DFS performance. The Advanced Dispersed Fringe Sensing (ADFS) Algorithm is designed to reduce the sensitivity to calibration errors by determining the optimal fringe extraction line. Applying an angular extraction line dithering procedure and combining this dithering process with an error function while minimizing the phase term of the fitted signal, defines in essence the ADFS algorithm.
Evolution of nuclear spectroscopy at Saha Institute of Nuclear Physics
Indian Academy of Sciences (India)
Currently Saha Institute is building a multi-element gamma heavy ion neutron array detector (MEGHNAD), which will have six high efficiency clover Ge detector together with charged particle ball and other accessories. The system is expected to be usable in 2002 and will be used in experiments using high energy heavy ...
A simple method of shower localization and identification in laterally segmented calorimeters
International Nuclear Information System (INIS)
Awes, T.C.; Obenshain, F.E.; Plasil, F.; Saini, S.; Young, G.R.; Sorensen, S.P.
1992-01-01
A method is proposed to calculate the first and second moments of the spatial distribution of the energy of electromagnetic and hadronic showers measured in laterally segmented colorimeters. The technique uses a logarithmic weighting of energy fraction observed in the individual detector cells. It is fast and simple requiring no fitting or complicated corrections for the position or angle of incidence. The method is demonstrated with GEANT simulations of a BGO detector array. The position resolution results and the e/π separation results are found to be equal or superior to those obtained with more complicated techniques. (orig.)
Directory of Open Access Journals (Sweden)
Angela E. Gradish
2016-07-01
Full Text Available Background. Bumble bees (Bombus spp. are important wild and managed pollinators. There is increased interest in incorporating data on bumble bees into risk assessments for pesticides, but standardized methods for assessing hazards of pesticides in semi-field and field settings have not yet been established for bumble bees. During semi-field studies, colonies are caged with pesticide-treated flowering surrogate plants, which must be attractive to foragers to ensure colony exposure to the test compound, and must produce an ample nectar and pollen to sustain colonies during testing. However, it is not known which plant(s are suitable for use in semi-field studies with bumble bees. Materials and Methods. We compared B. impatiens foraging activity and colony development on small plots of flowering buckwheat (Fagopyrum esculentum, var. common, red clover (Trifolium pratense, and purple tansy (Phacelia tanacetifolia under semi-field conditions to assess their suitability as surrogate plants for pesticide risk assessment studies with bumble bees. We also compared the growth characteristics and input requirements of each plant type. Results. All three plant types generally established and grew well. Red clover and purple tansy experienced significant weed pressure and/or insect pest damage. In contrast, pest pressure was extremely low in buckwheat. Overall, B. impatiens foraging activity was significantly greater on buckwheat plots than red clover or purple tansy, but plant type had no effect on number of individuals produced per colony or colony weight. Discussion. Because of the consistently high foraging activity and successful colony development observed on buckwheat plots, combined with its favourable growth characteristics and low maintenance requirements, we recommend buckwheat as a surrogate plant for use in semi-field pesticide toxicity assessments with B. impatiens.
Directory of Open Access Journals (Sweden)
Mohammad Hossein Ansari
2017-05-01
Full Text Available Effects of phosphate fertilizer and pseudomonas putida strains on the quantity and quality of forage of berseem clover as a second crop was studied in a factorial field experiment using randomized complete block design with three replications at Fooman, Guilan province, Iran. Treatments consisted of phosphate fertilizer with three levels (0, 75 and 150 kg/ha as triple super phosphate and Pseudomonas putida strains with four levels (M21, M5, M168 and control. The results showed that use of phosphate fertilizers increased the soil pH during growing season while bacterial inoculation adjusted soil pH. The bacterial inoculation increased amount of crude protein, digestible protein, acidic and alkaline phosphatase activity compared to non-inoculated treatment, but it decreased crude fiber of the forage. Clover forage yield, protein yield and phosphorus content of foliage also were influenced by the interaction of bacterial strains and phosphate fertilizer. The highest forage and protein yield were obtained by using strain M5+150 kg P ha-1. Significant increases in forage and protein yield were found to be 16.49% and 8.01%, respectively, as compared with non-inoculated treatment. Based on the result of this experiment, application of 150 kg P ha-1 and Pseudomonas putida strain M5 inoculation can be used to obtain highest forage yield and quality of berseem clover as second crop in the experimental site.
Hetta, M.; Cone, J.W.; Gustavsson, A.M.; Martinsson, K.
2003-01-01
The aim was to compare the effects of additives on direct cut silages of pure timothy and timothy mixed with tetraploid red clover. First and second growth cuts were ensiled during three consecutive years, 1994, 1995 and 1996, either without any additive or with the addition of formic acid, or
Measurement of β-decay end point energy with planar HPGe detector
Energy Technology Data Exchange (ETDEWEB)
Bhattacharjee, T., E-mail: btumpa@vecc.gov.in [Physics Group, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Pandit, Deepak [Physics Group, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Das, S.K. [RCD-BARC, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Chowdhury, A.; Das, P. [Physics Group, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Banerjee, D. [RCD-BARC, Variable Energy Cyclotron Centre, Kolkata 700 064 (India); Saha, A.; Mukhopadhyay, S.; Pal, S.; Banerjee, S.R. [Physics Group, Variable Energy Cyclotron Centre, Kolkata 700 064 (India)
2014-12-11
The β–γ coincidence measurement has been performed with a segmented planar Hyper-Pure Germanium (HPGe) detector and a single coaxial HPGe detector to determine the end point energies of nuclear β-decays. The experimental end point energies have been determined for some of the known β-decays in {sup 106}Rh→{sup 106}Pd. The end point energies corresponding to three weak branches in {sup 106}Rh→{sup 106}Pd decay have been measured for the first time. The γ ray and β particle responses for the planar HPGe detector were simulated using the Monte Carlo based code GEANT3. The experimentally obtained β spectra were successfully reproduced with the simulation.
CONTRIBUTION OF DIFFERENT PARTICLES MEASURED WITH TRACK ETCHED DETECTORS ONBOARD ISS.
Ambrožová, I; Davídková, M; Brabcová, K Pachnerová; Tolochek, R V; Shurshakov, V A
2017-09-29
Cosmic radiation consists of primary high-energy galactic and solar particles. When passing through spacecraft walls and astronauts' bodies, the spectrum becomes even more complex due to generating of secondary particles through fragmentation and nuclear interactions. Total radiation exposure is contributed by both these components. With an advantage, space research uses track etched detectors from the group of passive detectors visualizing the tracks of particles, in this case by etching. The detectors can discriminate between various components of cosmic radiation. A method is introduced for the separation of the different types of particles according to their range using track etched detectors. The method is demonstrated using detectors placed in Russian segment of the International Space Station in 2009. It is shown that the primary high-energy heavy ions with long range contribute up to 56% of the absorbed dose and up to 50% to the dose equivalent. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
A Geant4 simulation package for the TASISpec experimental detector setup
Energy Technology Data Exchange (ETDEWEB)
Sarmiento, L.G., E-mail: lgsarmientop@unal.edu.co [Universidad Nacional de Colombia, Bogota D.C. 111321 (Colombia); Lund University, S-22100 Lund (Sweden); Andersson, L.-L. [University of Liverpool, Oliver Lodge Laboratory, Liverpool L69 7ZE (United Kingdom); Rudolph, D. [Lund University, S-22100 Lund (Sweden)
2012-03-01
The experimental detector setup TASISpec (TA SCA in Small Image mode Spectroscopy) comprises composite Ge- and highly segmented Si-detectors. The setup is constructed to provide multi-coincidence spectroscopic data between {gamma}-rays, X-rays, conversion electrons, fission fragments, and {alpha}-particles for heavy and superheavy elements (Z{>=}100). The full array has been virtually constructed using the Geant4 simulation toolkit. The simulations will not only be used to explore the possibilities of the detector setup itself. More important, however, they will also shed light on the nuclear structure of the heaviest elements. This can be done by comparing the simulated detector response of complex decay modes with the experimental data. Such an iterative or 'self-consistent' way to understand experimental observables will provide more reliability when disentangling the data and deducing experimental decay schemes.
The silicon strips Inner Tracker (ITk) of the ATLAS Phase-II upgrade detector
AUTHOR|(INSPIRE)INSPIRE-00220523; The ATLAS collaboration
2018-01-01
The inner detector of the present ATLAS detector has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the next-generation tracking detector proposed for the High Luminosity LHC (HL-LHC), the so-called ATLAS Phase-II Upgrade, the particle densities and radiation levels will be higher by as much as a factor of ten. The new detectors must be faster, they need to be more highly segmented, and covering more area. They also need to be more resistant to radiation, and they require much greater power delivery to the front-end systems. At the same time, they cannot introduce excess material which could undermine performance. For those reasons, the inner tracker of the ATLAS detector must be redesigned and rebuilt completely. The inner detector of the current detector will be replaced by the Inner Tracker (ITk). It consists of an innermost pixel detector and an outer strips tracker. This contribution focuses on the strips tracker. The basic detection unit of the ...
Characterization and Calibration of Large Area Resistive Strip Micromegas Detectors
Losel, Philipp Jonathan; The ATLAS collaboration
2015-01-01
Resisitve strip Micromegas detectors behave discharge tolerant. They have been tested extensively as smaller detectors of about 10 x 10 cm$^2$ in size and they work reliably at high rates of 100\\,kHz/cm$^2$ and above. Tracking resolutions well below 100\\,$\\mu$m have been observed for 100 GeV muons and pions. Micromegas detectors are meanwhile proposed as large area muon precision trackers of 2-3\\,m$^2$ in size. To investigate possible differences between small and large detectors, a 1\\,m$^2$ detector with 2048 resistive strips at a pitch of 450 $\\mu$m was studied in the LMU Cosmic Ray Facility (CRF) using two 4 $\\times$ 2.2 m$^2$ large Monitored Drift Tube (MDT) chambers for cosmic muon reference tracking. Segmentation of the resistive strip anode plane in 57.6\\,mm x 95\\,mm large areas has been realized by the readout of 128 strips with one APV25 chip each and by 11 95\\,mm broad trigger scintillators placed along the readout strips.\\\\ This allows for mapping of homogenity in pulse height and efficiency, deter...
Development of a cadmium telluride pixel detector for astrophysical applications
Miyasaka, Hiromasa; Harrison, Fiona A.; Cook, Walter R.; Mao, Peter H.; Rana, Vikram R.; Ishikawa, Shin-Nosuke; Ushio, Masayoshi; Aono, Hiroyuki; Watanabe, Shin; Sato, Goro; Kokubun, Motohide; Takahashi, Tadayuki
2009-08-01
We are developing imaging Cadmium Telluride (CdTe) pixel detectors optimized for astrophysical hard X-ray applications. Our hybrid detector consist of a CdTe crystal 1mm thick and 2cm × 2cm in area with segmented anode contacts directly bonded to a custom low-noise application specific integrated circuit (ASIC). The CdTe sensor, fabricated by ACRORAD (Okinawa, Japan), has Schottky blocking contacts on a 605 micron pitch in a 32 × 32 array, providing low leakage current and enabling readout of the anode side. The detector is bonded using epoxy-gold stud interconnects to a custom low noise, low power ASIC circuit developed by Caltech's Space Radiation Laboratory. We have achieved very good energy resolution over a wide energy range (0.62keV FWHM @ 60keV, 10.8keV FWHM @ 662keV). We observe polarization effects at room temperature, but they are suppressed if we operate the detector at or below 0°C degree. These detectors have potential application for future missions such as the International X-ray Observatory (IXO).
Phase contrast image segmentation using a Laue analyser crystal
International Nuclear Information System (INIS)
Kitchen, Marcus J; Paganin, David M; Lewis, Robert A; Pavlov, Konstantin M; Uesugi, Kentaro; Allison, Beth J; Hooper, Stuart B
2011-01-01
Dual-energy x-ray imaging is a powerful tool enabling two-component samples to be separated into their constituent objects from two-dimensional images. Phase contrast x-ray imaging can render the boundaries between media of differing refractive indices visible, despite them having similar attenuation properties; this is important for imaging biological soft tissues. We have used a Laue analyser crystal and a monochromatic x-ray source to combine the benefits of both techniques. The Laue analyser creates two distinct phase contrast images that can be simultaneously acquired on a high-resolution detector. These images can be combined to separate the effects of x-ray phase, absorption and scattering and, using the known complex refractive indices of the sample, to quantitatively segment its component materials. We have successfully validated this phase contrast image segmentation (PCIS) using a two-component phantom, containing an iodinated contrast agent, and have also separated the lungs and ribcage in images of a mouse thorax. Simultaneous image acquisition has enabled us to perform functional segmentation of the mouse thorax throughout the respiratory cycle during mechanical ventilation.
DEFF Research Database (Denmark)
Jørgensen, F.V.; Jensen, E.S.
1997-01-01
The short-term effects of a simulated cattle dung pat on N-2 fixation and total uptake of N in a perennial ryegrass/white clover mixture was studied in a container experiment using sheep faeces mixed with water to a DM content of 13%. We used a new N-15 cross-labelling technique to determine...
Principal component analysis for neural electron/jet discrimination in highly segmented calorimeters
International Nuclear Information System (INIS)
Vassali, M.R.; Seixas, J.M.
2001-01-01
A neural electron/jet discriminator based on calorimetry is developed for the second-level trigger system of the ATLAS detector. As preprocessing of the calorimeter information, a principal component analysis is performed on each segment of the two sections (electromagnetic and hadronic) of the calorimeter system, in order to reduce significantly the dimension of the input data space and fully explore the detailed energy deposition profile, which is provided by the highly-segmented calorimeter system. It is shown that projecting calorimeter data onto 33 segmented principal components, the discrimination efficiency of the neural classifier reaches 98.9% for electrons (with only 1% of false alarm probability). Furthermore, restricting data projection onto only 9 components, an electron efficiency of 99.1% is achieved (with 3% of false alarm), which confirms that a fast triggering system may be designed using few components
Validation of Energy Expenditure Prediction Models Using Real-Time Shoe-Based Motion Detectors.
Lin, Shih-Yun; Lai, Ying-Chih; Hsia, Chi-Chun; Su, Pei-Fang; Chang, Chih-Han
2017-09-01
This study aimed to verify and compare the accuracy of energy expenditure (EE) prediction models using shoe-based motion detectors with embedded accelerometers. Three physical activity (PA) datasets (unclassified, recognition, and intensity segmentation) were used to develop three prediction models. A multiple classification flow and these models were used to estimate EE. The "unclassified" dataset was defined as the data without PA recognition, the "recognition" as the data classified with PA recognition, and the "intensity segmentation" as the data with intensity segmentation. The three datasets contained accelerometer signals (quantified as signal magnitude area (SMA)) and net heart rate (HR net ). The accuracy of these models was assessed according to the deviation between physically measured EE and model-estimated EE. The variance between physically measured EE and model-estimated EE expressed by simple linear regressions was increased by 63% and 13% using SMA and HR net , respectively. The accuracy of the EE predicted from accelerometer signals is influenced by the different activities that exhibit different count-EE relationships within the same prediction model. The recognition model provides a better estimation and lower variability of EE compared with the unclassified and intensity segmentation models. The proposed shoe-based motion detectors can improve the accuracy of EE estimation and has great potential to be used to manage everyday exercise in real time.
Gamma-ray tracking - A new detector concept for nuclear spectroscopy
International Nuclear Information System (INIS)
Gast, W.
2001-01-01
In the framework of an European collaboration the nest generation of large efficiency, high resolution spectrometers for nuclear spectroscopy is under development. The new spectrometers are large volume, segmented Ge-detectors featuring 3D position sensitivity in order to allow Gamma-Ray Tracking. That is, knowing the interaction positions and the energies released at each interaction, the track each gamma-ray follows during its scattering process inside the detector volume can be reconstructed on basis of the Compton-scattering formula. The resulting high add-back efficiency an effective granularity significantly improves peak-to-total ratio, efficiency, and Doppler-broadening of the spectrometer. In this contribution the states of the project concerning detector design and development of digital signal processing techniques to achieve an optimal 3D position sensitivity is presented. (authors)
Liquid Scintillation Detectors for High Energy Neutrinos
International Nuclear Information System (INIS)
Smith, Stefanie N.; Learned, John G.
2010-01-01
Large open volume (not segmented) liquid scintillation detectors have been generally dedicated to low energy neutrino measurements, in the MeV energy region. We describe the potential employment of large detectors (>1 kiloton) for studies of higher energy neutrino interactions, such as cosmic rays and long-baseline experiments. When considering the physics potential of new large instruments the possibility of doing useful measurements with higher energy neutrino interactions has been overlooked. Here we take into account Fermat's principle, which states that the first light to reach each PMT will follow the shortest path between that PMT and the point of origin. We describe the geometry of this process, and the resulting wavefront, which we are calling the 'Fermat surface', and discuss methods of using this surface to extract directional track information and particle identification. This capability may be demonstrated in the new long-baseline neutrino beam from Jaeri accelerator to the KamLAND detector in Japan. Other exciting applications include the use of Hanohano as a movable long-baseline detector in this same beam, and LENA in Europe for future long-baseline neutrino beams from CERN. Also, this methodology opens up the question as to whether a large liquid scintillator detector should be given consideration for use in a future long-baseline experiment from Fermilab to the DUSEL underground laboratory at Homestake.
Islam, Afsana; Leung, Susanna; Nikmatullah, Aluh; Dijkwel, Paul P; McManus, Michael T
2017-01-01
The response of plants to water deficiency or drought is a complex process, the perception of which is triggered at the molecular level before any visible morphological responses are detected. It was found that different groups of plant proteinase inhibitors (PIs) are induced and play an active role during abiotic stress conditions such as drought. Our previous work with the white clover ( Trifolium repens L.) Kunitz Proteinase Inhibitor ( Tr-KPI ) gene family showed that Tr-KPIs are differentially regulated to ontogenetic and biotic stress associated cues and that, at least some members of this gene family may be required to maintain cellular homeostasis. Altered cellular homeostasis may also affect abiotic stress responses and therefore, we aimed to understand if distinct Tr-PKI members function during drought stress. First, the expression level of three Tr-KPI genes, Tr-KPI1 , Tr-KPI2 , and Tr-KPI5 , was measured in two cultivars and one white clover ecotype with differing capacity to tolerate drought. The expression of Tr-KPI1 and Tr-KPI5 increased in response to water deficiency and this was exaggerated when the plants were treated with a previous period of water deficiency. In contrast, proline accumulation and increased expression of Tr-NCED1 , a gene encoding a protein involved in ABA biosynthesis, was delayed in plants that experienced a previous drought period. RNAi knock-down of Tr-KPI1 and Tr-KPI5 resulted in increased proline accumulation in leaf tissue of plants grown under both well-watered and water-deficit conditions. In addition, increased expression of genes involved in ethylene biosynthesis was found. The data suggests that Tr-KPIs , particularly Tr-KPI5 , have an explicit function during water limitation. The results also imply that the Tr-KPI family has different in planta proteinase targets and that the functions of this protein family are not solely restricted to one of storage proteins or in response to biotic stress.
Directory of Open Access Journals (Sweden)
Afsana Islam
2017-10-01
Full Text Available The response of plants to water deficiency or drought is a complex process, the perception of which is triggered at the molecular level before any visible morphological responses are detected. It was found that different groups of plant proteinase inhibitors (PIs are induced and play an active role during abiotic stress conditions such as drought. Our previous work with the white clover (Trifolium repens L. Kunitz Proteinase Inhibitor (Tr-KPI gene family showed that Tr-KPIs are differentially regulated to ontogenetic and biotic stress associated cues and that, at least some members of this gene family may be required to maintain cellular homeostasis. Altered cellular homeostasis may also affect abiotic stress responses and therefore, we aimed to understand if distinct Tr-PKI members function during drought stress. First, the expression level of three Tr-KPI genes, Tr-KPI1, Tr-KPI2, and Tr-KPI5, was measured in two cultivars and one white clover ecotype with differing capacity to tolerate drought. The expression of Tr-KPI1 and Tr-KPI5 increased in response to water deficiency and this was exaggerated when the plants were treated with a previous period of water deficiency. In contrast, proline accumulation and increased expression of Tr-NCED1, a gene encoding a protein involved in ABA biosynthesis, was delayed in plants that experienced a previous drought period. RNAi knock-down of Tr-KPI1 and Tr-KPI5 resulted in increased proline accumulation in leaf tissue of plants grown under both well-watered and water-deficit conditions. In addition, increased expression of genes involved in ethylene biosynthesis was found. The data suggests that Tr-KPIs, particularly Tr-KPI5, have an explicit function during water limitation. The results also imply that the Tr-KPI family has different in planta proteinase targets and that the functions of this protein family are not solely restricted to one of storage proteins or in response to biotic stress.
Gamma-ray tracking: Characterisation of the AGATA symmetric prototype detectors
International Nuclear Information System (INIS)
Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Dimmock, M.R.; Nelson, L.; Nolan, P.J.; Rigby, S.; Lazarus, I.; Simpson, J.; Medina, P.; Santos, C.; Parisel, C.
2007-01-01
Each major technical advance in gamma-ray detection devices has resulted in significant new insights into the structure of atomic nuclei. The next major step in gamma-ray spectroscopy involves achieving the goal of a 4pi ball of Germanium detectors by using the technique of gamma-ray energy tracking in electrically segmented Germanium crystals. The resulting spectrometer will have an unparalleled level of detection power for nuclear electromagnetic radiation. Collaborations have been established in Europe (AGATA) [J. Simpson, Acta Phys. Pol. B 36 (2005) 1383. ] and the USA (GRETA/GRETINA) to build gamma-ray tracking spectrometers. This paper discusses the performance of the AGATA (Advanced Gamma Tracking Array) symmetric prototype detectors that have been tested at University of Liverpool. The use of a fully digital data acquisition system has allowed detector charge pulse shapes from a selection of well defined photon interaction positions to be analysed, yielding important information on the position sensitivity of the detector
Gamma-ray tracking: Characterisation of the AGATA symmetric prototype detectors
Energy Technology Data Exchange (ETDEWEB)
Boston, A.J. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom)]. E-mail: ajboston@liv.ac.uk; Boston, H.C. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Cresswell, J.R. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Dimmock, M.R. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Nelson, L. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Nolan, P.J. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Rigby, S. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Lazarus, I. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Simpson, J. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Medina, P. [Institut de Recherches Subatomiques, Strasbourg BP28 67037 (France); Santos, C. [Institut de Recherches Subatomiques, Strasbourg BP28 67037 (France); Parisel, C. [Institut de Recherches Subatomiques, Strasbourg BP28 67037 (France)
2007-08-15
Each major technical advance in gamma-ray detection devices has resulted in significant new insights into the structure of atomic nuclei. The next major step in gamma-ray spectroscopy involves achieving the goal of a 4pi ball of Germanium detectors by using the technique of gamma-ray energy tracking in electrically segmented Germanium crystals. The resulting spectrometer will have an unparalleled level of detection power for nuclear electromagnetic radiation. Collaborations have been established in Europe (AGATA) [J. Simpson, Acta Phys. Pol. B 36 (2005) 1383. ] and the USA (GRETA/GRETINA) to build gamma-ray tracking spectrometers. This paper discusses the performance of the AGATA (Advanced Gamma Tracking Array) symmetric prototype detectors that have been tested at University of Liverpool. The use of a fully digital data acquisition system has allowed detector charge pulse shapes from a selection of well defined photon interaction positions to be analysed, yielding important information on the position sensitivity of the detector.
Characterization of large volume HPGe detectors. Part II: Experimental results
International Nuclear Information System (INIS)
Bruyneel, Bart; Reiter, Peter; Pascovici, Gheorghe
2006-01-01
Measurements on a 12-fold segmented, n-type, large volume, irregular shaped HPGe detector were performed in order to determine the parameters of anisotropic mobility for electrons and holes as charge carriers created by γ-ray interactions. To characterize the electron mobility the complete outer detector surface was scanned in small steps employing photopeak interactions at 60keV. A precise measurement of the hole drift anisotropy was performed with 356keV γ-rays. The drift velocity anisotropy and crystal geometry cause considerable rise time differences in pulse shapes depending on the position of the spatial charge carrier creation. Pulse shapes of direct and transient signals are reproduced by weighting potential calculations with high precision. The measured angular dependence of rise times is caused by the anisotropic mobility, crystal geometry, changing field strength and space charge effects. Preamplified signals were processed employing digital spectroscopy electronics. Response functions, crosstalk contributions and averaging procedures were taken into account implying novel methods due to the segmentation of the Ge-crystal and digital signal processing electronics
An attenuation measurement technique for rotating planar detector positron tomographs
International Nuclear Information System (INIS)
McNeil, P.A.; Julyan, P.J.; Parker, D.J.
1997-01-01
This paper presents a new attenuation measurement technique suitable for rotating planar detector positron tomographs. Transmission measurements are made using two unshielded positron-emitting line sources, one attached to the front face of each detector. Many of the scattered and accidental coincidences are rejected by including only those coincidences that form a vector passing within a predetermined distance of either line source. Some scattered and accidental coincidences are still included, which reduces the measured linear attenuation; in principle their contribution can be accurately estimated and subtracted, but in practice, when limited statistics are available (as is the case with the multi-wire Birmingham positron camera), this background subtraction unacceptably increases the noise. Instead an attenuation image having the correct features can be reconstructed from the measured projections. For objects containing only a few discrete linear attenuation coefficients, segmentation of this attenuation image reduces noise and allows the correct linear attenuation coefficients to be restored by renormalization. Reprojection through the segmented image may then provide quantitatively correct attenuation correction factors of sufficient statistical quality to correct for attenuation in PET emission images. (author)
Energy Technology Data Exchange (ETDEWEB)
Kitajima, Kazuhiro, E-mail: kitajima@med.kobe-u.ac.jp [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Maeda, Tetsuo; Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Division of Radiology, Kobe University Hospital, Kobe (Japan); Yoshikawa, Takeshi [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Konishi, Minoru [Division of Radiology, Kobe University Hospital, Kobe (Japan); Kanda, Tomonori; Onishi, Yumiko; Matsumoto, Keiko; Koyama, Hisanobu; Takenaka, Daisuke; Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan)
2011-11-15
Objective: To compare the capability of 320-detector row CT (area-detector CT: ADCT) with step-and-shoot scan protocol for small abdominal vasculature assessment with that of 64-detector row CT with helical scan protocol. Materials and methods: Total of 60 patients underwent contrast-enhanced abdominal CT for preoperative assessment. Of all, 30 suspected to have lung cancer underwent ADCT using step-and-shoot scan protocol. The other 30 suspected to have renal cell carcinoma underwent 64-MDCT using helical scan protocol. Two experienced radiologists independently assessed inferior epigastric, hepatic subsegmental (in the segment 8), mesenteric marginal (Griffith point) and inferior phrenic arteries by using 5-point visual scoring systems. Kappa analysis was used for evaluation of interobserver agreement. To compare the visualization capability of the two systems, the Mann-Whitney U-test was used to compare the scores for each of the arteries. Results: Overall interobserver agreements for both systems were almost perfect ({kappa} > 0.80). Visualization scores for inferior epigastric and mesenteric arteries were significantly higher for ADCT than for 64-detector row CT (p < 0.05). No significant difference was found for hepatic subsegmental and inferior phrenic arteries. Conclusion: Small abdominal vasculature assessment by ADCT with step-and-shoot scan protocol is potentially equal to or better than that by 64-detector row CT with helical scan protocol.
International Nuclear Information System (INIS)
Kitajima, Kazuhiro; Maeda, Tetsuo; Ohno, Yoshiharu; Yoshikawa, Takeshi; Konishi, Minoru; Kanda, Tomonori; Onishi, Yumiko; Matsumoto, Keiko; Koyama, Hisanobu; Takenaka, Daisuke; Sugimura, Kazuro
2011-01-01
Objective: To compare the capability of 320-detector row CT (area-detector CT: ADCT) with step-and-shoot scan protocol for small abdominal vasculature assessment with that of 64-detector row CT with helical scan protocol. Materials and methods: Total of 60 patients underwent contrast-enhanced abdominal CT for preoperative assessment. Of all, 30 suspected to have lung cancer underwent ADCT using step-and-shoot scan protocol. The other 30 suspected to have renal cell carcinoma underwent 64-MDCT using helical scan protocol. Two experienced radiologists independently assessed inferior epigastric, hepatic subsegmental (in the segment 8), mesenteric marginal (Griffith point) and inferior phrenic arteries by using 5-point visual scoring systems. Kappa analysis was used for evaluation of interobserver agreement. To compare the visualization capability of the two systems, the Mann-Whitney U-test was used to compare the scores for each of the arteries. Results: Overall interobserver agreements for both systems were almost perfect (κ > 0.80). Visualization scores for inferior epigastric and mesenteric arteries were significantly higher for ADCT than for 64-detector row CT (p < 0.05). No significant difference was found for hepatic subsegmental and inferior phrenic arteries. Conclusion: Small abdominal vasculature assessment by ADCT with step-and-shoot scan protocol is potentially equal to or better than that by 64-detector row CT with helical scan protocol.
Forward instrumentation for ILC detectors
Energy Technology Data Exchange (ETDEWEB)
Abramowicz, Halina [Tel Aviv Univ. (Israel); Abusleme, Angel [Stanford Univ., CA (United States); Afanaciev, Konstantin [NCPHEP, Minsk (BY)] (and others)
2010-09-15
Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10{sup -3} and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised. (orig.)
Forward instrumentation for ILC detectors
International Nuclear Information System (INIS)
Abramowicz, Halina; Abusleme, Angel; Afanaciev, Konstantin
2010-09-01
Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10 -3 and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised. (orig.)
Forward Instrumentation for ILC Detectors
Abramowicz, Halina; Afanaciev, Konstantin; Aguilar, Jonathan; Ambalathankandy, Prasoon; Bambade, Philip; Bergholz, Matthias; Bozovic-Jelisavcic, Ivanka; Castro, Elena; Chelkov, Georgy; Coca, Cornelia; Daniluk, Witold; Dragone, Angelo; Dumitru, Laurentiu; Elsener, Konrad; Emeliantchik, Igor; Fiutowski, Tomasz; Gostkin, Mikhail; Grah, Christian; Grzelak, Grzegorz; Haller, Gunter; Henschel, Hans; Ignatenko, Alexandr; Idzik, Marek; Ito, Kazutoshi; Jovin, Tatjana; Kielar, Eryk; Kotula, Jerzy; Krumstein, Zinovi; Kulis, Szymon; Lange, Wolfgang; Lohmann, Wolfgang; Levy, Aharon; Moszczynski, Arkadiusz; Nauenberg, Uriel; Novgorodova, Olga; Ohlerich, Marin; Orlandea, Marius; Oleinik, Gleb; Oliwa, Krzysztof; Olshevski, Alexander; Pandurovic, Mila; Pawlik, Bogdan; Przyborowski, Dominik; Sato, Yutaro; Sadeh, Iftach; Sailer, Andre; Schmidt, Ringo; Schumm, Bruce; Schuwalow, Sergey; Smiljanic, Ivan; Swientek, Krzysztof; Takubo, Yosuke; Teodorescu, Eliza; Wierba, Wojciech; Yamamoto, Hitoshi; Zawiejski, Leszek; Zhang, Jinlong
2010-01-01
Two special calorimeters are foreseen for the instrumentation of the very forward region of the ILC detector, a luminometer designed to measure the rate of low angle Bhabha scattering events with a precision better than 10-3 and a low polar angle calorimeter, adjacent to the beam-pipe. The latter will be hit by a large amount of beamstrahlung remnants. The amount and shape of these depositions will allow a fast luminosity estimate and the determination of beam parameters. The sensors of this calorimeter must be radiation hard. Both devices will improve the hermeticity of the detector in the search for new particles. Finely segmented and very compact calorimeters will match the requirements. Due to the high occupancy fast front-end electronics is needed. The design of the calorimeters developed and optimised with Monte Carlo simulations is presented. Sensors and readout electronics ASICs have been designed and prototypes are available. Results on the performance of these major components are summarised.
Energy Technology Data Exchange (ETDEWEB)
Abdel-Rehim, Abdou; Kallidonis, Christos; Koutsou, Giannis [Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center; Alexandrou, Constantia; Constantinou, Martha; Hadjiyiannakou, Kyriakos [Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center; Cyprus Univ. (Cyprus). Dept. of Physics; Jansen, Karl [DESY Zeuthen (Germany). NIC; Aviles-Casco, Alejandro Vaquero [INFN Sezione di Milano-Bicocca, Milano (Italy)
2015-11-15
We compute the disconnected quark loops contributions entering the determination of nucleon observables, by using a N{sub f}=2 ensemble of twisted mass fermions with a clover term at a pion mass m{sub π}=133 MeV. We employ exact deflation and implement all calculations in GPUs, enabling us to achieve large statistics and a good signal.
Justin, G.B.; Julich, R.; Payne, K.L.
2009-01-01
Selected groundwater level hydrographs for the Chambers-Clover Creek watershed (CCCW) and vicinity, Washington, are presented in an interactive web-based map to illustrate changes in groundwater levels in and near the CCCW on a monthly and seasonal basis. Hydrographs are linked to points corresponding to the well location on an interactive map of the study area. Groundwater level data and well information from Federal, State, and local agencies were obtained from the U.S. Geological Survey National Water Information System (NWIS), Groundwater Site Inventory (GWSI) System.
International Nuclear Information System (INIS)
Heijne, Erik H.M.
2008-01-01
Silicon nuclear particle detectors were introduced just 50 years ago, after single crystal manufacturing was mastered. A major change took place around 1980 when the 'planar' Metal Oxide Semiconductor (MOS) technology developed in microelectronics was systematically applied also in detector construction. With the simultaneous introduction of matched readout chips this eventually would lead to pixelized matrix detectors that function as radiation imaging devices. The critical contributions to this revolution by Josef Kemmer and Paul Burger are described. Performance of the segmented planar technology detectors improved significantly in comparison with the earlier spectrometric diodes. With efficient industrial support the use of silicon detectors in many new applications has become possible and detector systems with a sensitive area of several tens to >100m 2 have been constructed recently
Energy Technology Data Exchange (ETDEWEB)
Howard, Chris [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Daigle, Stephen [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Buckner, Matt [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Erikson, Luke E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Runkle, Robert C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stave, Sean C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Champagne, Art [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Cooper, Andrew [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Downen, Lori [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Glasgow, Brian D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kelly, Keegan [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States); Sallaska, Anne [Univ. of North Carolina, Chapel Hill, NC (United States); Triangle Univ. Nuclear Lab., Durham, NC (United States)
2015-02-18
The Multi-sensor Airborne Radiation Survey (MARS) detector is a 14-crystal array of high-purity germanium (HPGe) detectors housed in a single cryostat. The array was used to measure the astrophysical S-factor for the 14N(p,γ)15O* reaction for several transition energies at an effective center of mass energy of 163 keV. Owing to the segmented nature of the MARS detector, the effect of gamma-ray summing was greatly reduced in comparison to past experiments which utilized large, single-crystal detectors. The new S-factor values agree within the uncertainties with the past measurements. Details of the analysis and detector performance will be presented.
Segmentation: Identification of consumer segments
DEFF Research Database (Denmark)
Høg, Esben
2005-01-01
It is very common to categorise people, especially in the advertising business. Also traditional marketing theory has taken in consumer segments as a favorite topic. Segmentation is closely related to the broader concept of classification. From a historical point of view, classification has its...... origin in other sciences as for example biology, anthropology etc. From an economic point of view, it is called segmentation when specific scientific techniques are used to classify consumers to different characteristic groupings. What is the purpose of segmentation? For example, to be able to obtain...... a basic understanding of grouping people. Advertising agencies may use segmentation totarget advertisements, while food companies may usesegmentation to develop products to various groups of consumers. MAPP has for example investigated the positioning of fish in relation to other food products...
PixTrig: a Level 2 track finding algorithm based on pixel detector
Baratella, A; Morettini, P; Parodi, F
2000-01-01
This note describes an algorithm for track search at Level 2 based on pixel detector. Using three pixel clusters we can produce a reconstruction of the track parameter in both z and R-phi plane. These track segments can be used as seed for more sophisticated track finding algorithms or used directly, especially when impact parameter resolution is crucial. The algorithm efficiency is close to 90% for pt > 1 GeV/c and the processing time is small enough to allow a complete detector reconstruction (non RoI guided) within the Level 2 processing.
Kondo, Hideki; Hisano, Sakae; Chiba, Sotaro; Maruyama, Kazuyuki; Andika, Ida Bagus; Toyoda, Kazuhiro; Fujimori, Fumihiro; Suzuki, Nobuhiro
2016-02-02
The identification of mycoviruses contributes greatly to understanding of the diversity and evolutionary aspects of viruses. Powdery mildew fungi are important and widely studied obligate phytopathogenic agents, but there has been no report on mycoviruses infecting these fungi. In this study, we used a deep sequencing approach to analyze the double-stranded RNA (dsRNA) segments isolated from field-collected samples of powdery mildew fungus-infected red clover plants in Japan. Database searches identified the presence of at least ten totivirus (genus Totivirus)-like sequences, termed red clover powdery mildew-associated totiviruses (RPaTVs). The majority of these sequences shared moderate amino acid sequence identity with each other (powdery mildew fungus populations infecting red clover plants in the field. Copyright © 2015 Elsevier B.V. All rights reserved.
Kondo, Hideki; Hisano, Sakae; Chiba, Sotaro; Maruyama, Kazuyuki; Andika, Ida Bagus; Toyoda, Kazuhiro; Fujimori, Fumihiro; Suzuki, Nobuhiro
2016-07-02
The identification of mycoviruses contributes greatly to understanding of the diversity and evolutionary aspects of viruses. Powdery mildew fungi are important and widely studied obligate phytopathogenic agents, but there has been no report on mycoviruses infecting these fungi. In this study, we used a deep sequencing approach to analyze the double-stranded RNA (dsRNA) segments isolated from field-collected samples of powdery mildew fungus-infected red clover plants in Japan. Database searches identified the presence of at least ten totivirus (genus Totivirus)-like sequences, termed red clover powdery mildew-associated totiviruses (RPaTVs). The majority of these sequences shared moderate amino acid sequence identity with each other (powdery mildew fungus populations infecting red clover plants in the field. Copyright © 2015 Elsevier B.V. All rights reserved.
The Argonne silicon strip-detector array
Energy Technology Data Exchange (ETDEWEB)
Wuosmaa, A H; Back, B B; Betts, R R; Freer, M; Gehring, J; Glagola, B G; Happ, Th; Henderson, D J; Wilt, P [Argonne National Lab., IL (United States); Bearden, I G [Purdue Univ., Lafayette, IN (United States). Dept. of Physics
1992-08-01
Many nuclear physics experiments require the ability to analyze events in which large numbers of charged particles are detected and identified simultaneously, with good resolution and high efficiency, either alone, or in coincidence with gamma rays. The authors have constructed a compact large-area detector array to measure these processes efficiently and with excellent energy resolution. The array consists of four double-sided silicon strip detectors, each 5x5 cm{sup 2} in area, with front and back sides divided into 16 strips. To exploit the capability of the device fully, a system to read each strip-detector segment has been designed and constructed, based around a custom-built multi-channel preamplifier. The remainder of the system consists of high-density CAMAC modules, including multi-channel discriminators, charge-sensing analog-to-digital converters, and time-to-digital converters. The array`s performance has been evaluated using alpha-particle sources, and in a number of experiments conducted at Argonne and elsewhere. Energy resolutions of {Delta}E {approx} 20-30 keV have been observed for 5 to 8 MeV alpha particles, as well as time resolutions {Delta}T {<=} 500 ps. 4 figs.
Decay spectroscopy of neutron-rich nuclei around {sup 37,38}Al
Energy Technology Data Exchange (ETDEWEB)
Steiger, Konrad [Physik-Department E12, Technische Universitaet Muenchen (Germany); Collaboration: CAITEN-Collaboration
2013-07-01
An experiment at RIBF (Radioactive Isotope Beam Factory at RIKEN, Japan) investigated N=20 nuclei above {sup 29}F and the midshell region around {sup 37}Al. These nuclei were produced by relativistic projectile fragmentation of a 345 AMeV {sup 48}Ca primary beam from the superconducting ring cyclotron SRC with an average intensity of 70 pnA. The secondary cocktail beam was separated and identified with the BigRIPS fragment separator and the ZeroDegree spectrometer. The identified fragments were implanted in the CAITEN detector (Cylindrical Active Implantation Target for Efficient Nuclear-decay study). The main part of this detector is a highly segmented plastic scintillator with the shape of a hollow cylinder. To reduce background decay events the scintillator was moved axially and vertically similar to a tape-transport system. Implantations and decays were correlated in time and space. For the first time β-delayed γ-rays were measured in the neutron-rich isotopes {sup 37,38}Si (with three germanium clover detectors). From β-γ-γ coincidences partial level schemes could be constructed. The results were compared to shell model calculations and a tentative assignment for spins and parities of the experimental level schemes was possible. Significantly more precise half-lives for the implanted nuclei were measured.
Gebauer, B; Richter, G; Levchanovsky, F V; Nikiforov, A
2001-01-01
For thermal neutron imaging at the next generation of high-flux pulsed neutron sources a large area and fourfold segmented, hybrid, low-pressure, two-dimensional position sensitive, microstrip gas chamber detector, fabricated in a multilayer technology on glass substrates, is presently being developed, which utilizes a thin composite sup 1 sup 5 sup 7 Gd/CsI neutron converter. The present article focusses on the readout scheme and the data acquisition (DAQ) system. For position encoding, interpolating and fast multihit delay line based electronics is applied with up to eightfold sub-segmentation per geometrical detector segment. All signals, i.e. position, time-of-flight and pulse-height signals, are fed into deadtime-less 8-channel multihit TDC chips with 120 ps LSB via constant fraction and time-over-threshold discriminators, respectively. The multihit capability is utilized to raise the count rate limit in combination with a sum check algorithm for disentangling pulses from different events. The first vers...
Characterization and Calibration of Large Area Resistive Strip Micromegas Detectors
AUTHOR|(INSPIRE)INSPIRE-00389527; The ATLAS collaboration
2016-01-01
Resistive strip Micromegas detectors are discharge tolerant. They have been tested extensively as small detectors of about 10 x 10 cm$^2$ in size and they work reliably at high rates of 100 kHz/cm$^2$ and above. Tracking resolution well below 100 $\\mu$m has been observed for 100 GeV muons and pions. Micromegas detectors are meanwhile proposed as large area muon precision trackers of 2-3 m$^2$ in size. To investigate possible differences between small and large detectors, a 1 m$^2$ detector with 2048 resistive strips at a pitch of 450 $\\mu$m was studied in the LMU Cosmic Ray Measurement Facility (CRMF) using two 4 $\\times$ 2.2 m$^2$ large Monitored Drift Tube (MDT) chambers for cosmic muon reference tracking. A segmentation of the resistive strip anode plane in 57.6 mm x 93 mm large areas has been realized by the readout of 128 strips with one APV25 chip each and by eleven 93 mm broad trigger scintillators placed along the readout strips. This allows for mapping of homogeneity in pulse height and efficiency, d...
Alpha-event and surface characterisation in segmented true-coaxial HPGe detectors
Energy Technology Data Exchange (ETDEWEB)
Abt, I.; Garbini, L., E-mail: luciagarbini86@gmail.com.mpg.de; Gooch, C.; Irlbeck, S.; Liu, X.; Palermo, M.; Schulz, O.
2017-06-21
A detailed study of alpha interactions on the passivation layer on the end-plate of a true-coaxial high-purity germanium detector is presented. The observation of alpha events on such a surface indicates an unexpectedly thin so-called “effective dead layer” of less than 20 µm thickness. In addition, the influence of the metalisation close to the end-plate on the time evolution of the output pulses is discussed. The results indicate that alpha contamination can result in events which could be mistaken as signals for neutrinoless double beta decay and provide some guidance on how to prevent this.
Two large-area anode-pad MICROMEGAS chambers as the basic elements of a pre-shower detector
Aphecetche, L; D'Enterria, D G; Le Guay, M; Li, X; Martínez, G; Mora, M J; Pichot, P; Roy, D; Schutz, Y
2001-01-01
The design of a detector based on MICROMEGAS (MICRO MEsh GAseous Structure) technology is presented. Our detector is characterized by a large active area of 398(\\times)281 mm(^{2}), a pad read-out with 20(\\times)22 mm(^{2}) segmentation, and an uniform amplification gap obtained by insulating spacers (100 (\\mu)m high and 200 (\\mu)m in diameter). The performances of several prototypes have been evaluated under irradiation with secondary beams of 2 GeV/c momentum charged pions and electrons. We consider such a detector as the basic element for a pre-shower detector to equip the PHOton Spectrometer (PHOS) of the ALICE experiment. Its assets are modularity, small amount of material, robustness and low cost.
Kusumoto, Dai; Goldwasser, Yaakov; Xie, Xiaonan; Yoneyama, Kaori; Takeuchi, Yasutomo; Yoneyama, Koichi
2007-09-01
Obligate root holoparasites of the genus Orobanche attack dicotyledonous crops and cause severe losses in many parts of the world. Chemical induction of plant defence systems such as systemic acquired resistance was proposed to be an available strategy to control the root parasite, but the detailed mechanisms involved have not been clarified. The aim of this study was to elucidate the effects of salicylic acid (SA), jasmonic acid (JA) and their analogues on resistance of red clover to Orobanche parasitism. Roots of red clover grown in plastic chambers were applied with SA, S-methyl benzo[1,2,3]thiadiazole-7-carbothioate (BTH), methyl jasmonate (MeJA) and n-propyl dihydrojasmonate (PDJ), and then were inoculated with O. minor seeds. Attachments of the parasite were observed after 5 weeks. SA and BTH, inducers of SA-mediated defences, significantly reduced the number of established parasites by more than 75 %. By contrast, MeJA and PDJ, inducers of JA-mediated defences, did not affect parasitism. The reduction in the number of established parasites by SA and BTH was due to the inhibited elongation of O. minor radicles and the activation of defence responses in the host root including lignification of the endodermis. These results suggest that SA-induced resistance, but not JA-induced resistance, is effective in inhibiting Orobanche parasitism and that the resistance is expressed by the host root both externally and internally.
Construction of the new silicon microstrips tracker for the Phase-II ATLAS detector
Liang, Zhijun; The ATLAS collaboration
2018-01-01
The inner detector of the present ATLAS detector has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the next-generation tracking detector proposed for the High Luminosity LHC (HL-LHC), the so-called ATLAS Phase-II Upgrade, the particle densities and radiation levels will be higher by as much as a factor of ten. The new detectors must be faster, they need to be more highly segmented, and covering more area. They also need to be more resistant to radiation, and they require much greater power delivery to the front-end systems. For those reasons, the inner tracker of the ATLAS detector must be redesigned and rebuilt completely. The design of the ATLAS Upgrade inner tracker (ITk) has already been defined. It consists of several layers of silicon particle detectors. The innermost layers will be composed of silicon pixel sensors, and the outer layers will consist of silicon microstrip sensors. This paper will focus on the latest research and development act...
Effects of Seeding Density and Nitrogen Fertilizer on the Productivity of Egyptian Clover
Directory of Open Access Journals (Sweden)
Jwan G. Rafaat
2013-11-01
Full Text Available The study was carried out to show the effect of different levels of nitrogen fertilizer 0, 20, 40 and 60 kg urea/ha, and two seeding rates 15 and 30 kg/ha. The study was conducted at Bakrajo research field during the winter season 2011-2012 to some growth characteristics of Egyptian clover, such as plant height, dry leaf weight percent, dry stem weight percent, leave stem ratio, fresh yield t/ha, dry yield t/ha and dry matter percent. The experiment was designed as (R.C.B.D. The results can be summarized as follow; significant differences were observed between all three cuts, and the third cut was superior in almost characters especially in the forage yield. The application of 40 and 60 kg urea gave maximum yield. Using 15 kg seeds/ha showed superior value due to fresh yield in compare to 30 kg for all cutting, while the dry yield responded non-significantly to seeding rates.
Xiang, D.; Ni, W.; Zhang, H.; Wu, J.; Yan, W.; Su, Y.
2017-09-01
Superpixel segmentation has an advantage that can well preserve the target shape and details. In this research, an adaptive polarimetric SLIC (Pol-ASLIC) superpixel segmentation method is proposed. First, the spherically invariant random vector (SIRV) product model is adopted to estimate the normalized covariance matrix and texture for each pixel. A new edge detector is then utilized to extract PolSAR image edges for the initialization of central seeds. In the local iterative clustering, multiple cues including polarimetric, texture, and spatial information are considered to define the similarity measure. Moreover, a polarimetric homogeneity measurement is used to automatically determine the tradeoff factor, which can vary from homogeneous areas to heterogeneous areas. Finally, the SLIC superpixel segmentation scheme is applied to the airborne Experimental SAR and PiSAR L-band PolSAR data to demonstrate the effectiveness of this proposed segmentation approach. This proposed algorithm produces compact superpixels which can well adhere to image boundaries in both natural and urban areas. The detail information in heterogeneous areas can be well preserved.
Directory of Open Access Journals (Sweden)
D. Xiang
2017-09-01
Full Text Available Superpixel segmentation has an advantage that can well preserve the target shape and details. In this research, an adaptive polarimetric SLIC (Pol-ASLIC superpixel segmentation method is proposed. First, the spherically invariant random vector (SIRV product model is adopted to estimate the normalized covariance matrix and texture for each pixel. A new edge detector is then utilized to extract PolSAR image edges for the initialization of central seeds. In the local iterative clustering, multiple cues including polarimetric, texture, and spatial information are considered to define the similarity measure. Moreover, a polarimetric homogeneity measurement is used to automatically determine the tradeoff factor, which can vary from homogeneous areas to heterogeneous areas. Finally, the SLIC superpixel segmentation scheme is applied to the airborne Experimental SAR and PiSAR L-band PolSAR data to demonstrate the effectiveness of this proposed segmentation approach. This proposed algorithm produces compact superpixels which can well adhere to image boundaries in both natural and urban areas. The detail information in heterogeneous areas can be well preserved.
SiD Linear Collider Detector R&D, DOE Final Report
Energy Technology Data Exchange (ETDEWEB)
Brau, James E. [Univ. of Oregon, Eugene, OR (United States); Demarteau, Marcel [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-05-15
The Department of Energy’s Office of High Energy Physics supported the SiD university detector R&D projects in FY10, FY11, and FY12 with no-cost extensions through February, 2015. The R&D projects were designed to advance the SiD capabilities to address the fundamental questions of particle physics at the International Linear Collider (ILC): • What is the mechanism responsible for electroweak symmetry breaking and the generation of mass? • How do the forces unify? • Does the structure of space-time at small distances show evidence for extra dimensions? • What are the connections between the fundamental particles and forces and cosmology? Silicon detectors are used extensively in SiD and are well-matched to the challenges presented by ILC physics and the ILC machine environment. They are fast, robust against machine-induced background, and capable of very fine segmentation. SiD is based on silicon tracking and silicon-tungsten sampling calorimetry, complemented by powerful pixel vertex detection, and outer hadronic calorimetry and muon detection. Radiation hard forward detectors which can be read out pulse by pulse are required. Advanced calorimetry based on a particle flow algorithm (PFA) provides excellent jet energy resolution. The 5 Tesla solenoid is outside the calorimeter to improve energy resolution. PFA calorimetry requires fine granularity for both electromagnetic and hadronic calorimeters, leading naturally to finely segmented silicon-tungsten electromagnetic calorimetry. Since silicon-tungsten calorimetry is expensive, the detector architecture is compact. Precise tracking is achieved with the large magnetic field and high precision silicon microstrips. An ancillary benefit of the large magnetic field is better control of the e⁺e⁻ pair backgrounds, permitting a smaller radius beampipe and improved impact parameter resolution. Finally, SiD is designed with a cost constraint in mind. Significant advances and new capabilities have been made and
Real-Time Accumulative Computation Motion Detectors
Directory of Open Access Journals (Sweden)
Saturnino Maldonado-Bascón
2009-12-01
Full Text Available The neurally inspired accumulative computation (AC method and its application to motion detection have been introduced in the past years. This paper revisits the fact that many researchers have explored the relationship between neural networks and finite state machines. Indeed, finite state machines constitute the best characterized computational model, whereas artificial neural networks have become a very successful tool for modeling and problem solving. The article shows how to reach real-time performance after using a model described as a finite state machine. This paper introduces two steps towards that direction: (a A simplification of the general AC method is performed by formally transforming it into a finite state machine. (b A hardware implementation in FPGA of such a designed AC module, as well as an 8-AC motion detector, providing promising performance results. We also offer two case studies of the use of AC motion detectors in surveillance applications, namely infrared-based people segmentation and color-based people tracking, respectively.
GEM - A novel gaseous particle detector
Meinschad, T
2005-01-01
The work carried out within the framework of this Ph.D. deals with the construction of gaseous prototype detectors using Gas Electron Multiplier electrodes for the amplification of charges released by ionizing particles. The Gas Electron Multiplier (GEM) is a thin metal-clad polymer foil, etched with a high density of narrow holes, typically 50-100mm-2. On the application of a potential difference between the conductive top and bottom sides each hole acts as independent proportional counter. This new fast device permits to reach large amplification factors at high rates with a strong photon and ion-mediated feedback suppression due to the avalanche confinement in the GEM-holes. Here, in particular studies have been performed, which should prove, that the GEM-technology is applicable for an efficient measurement of single Cherenkov photons. These UV-photons can be detected in different ways. An elegant solution to develop large area RICH-detectors is to evaporate a pad-segmented readout-cathode of a multi-wire...
Performance evaluation of a high-resolution brain PET scanner using four-layer MPPC DOI detectors
Watanabe, Mitsuo; Saito, Akinori; Isobe, Takashi; Ote, Kibo; Yamada, Ryoko; Moriya, Takahiro; Omura, Tomohide
2017-09-01
A high-resolution positron emission tomography (PET) scanner, dedicated to brain studies, was developed and its performance was evaluated. A four-layer depth of interaction detector was designed containing five detector units axially lined up per layer board. Each of the detector units consists of a finely segmented (1.2 mm) LYSO scintillator array and an 8 × 8 array of multi-pixel photon counters. Each detector layer has independent front-end and signal processing circuits, and the four detector layers are assembled as a detector module. The new scanner was designed to form a detector ring of 430 mm diameter with 32 detector modules and 168 detector rings with a 1.2 mm pitch. The total crystal number is 655 360. The transaxial and axial field of views (FOVs) are 330 mm in diameter and 201.6 mm, respectively, which are sufficient to measure a whole human brain. The single-event data generated at each detector module were transferred to the data acquisition servers through optical fiber cables. The single-event data from all detector modules were merged and processed to create coincidence event data in on-the-fly software in the data acquisition servers. For image reconstruction, the high-resolution mode (HR-mode) used a 1.2 mm2 crystal segment size and the high-speed mode (HS-mode) used a 4.8 mm2 size by collecting 16 crystal segments of 1.2 mm each to reduce the computational cost. The performance of the brain PET scanner was evaluated. For the intrinsic spatial resolution of the detector module, coincidence response functions of the detector module pair, which faced each other at various angles, were measured by scanning a 0.25 mm diameter 22Na point source. The intrinsic resolutions were obtained with 1.08 mm full width at half-maximum (FWHM) and 1.25 mm FWHM on average at 0 and 22.5 degrees in the first layer pair, respectively. The system spatial resolutions were less than 1.0 mm FWHM throughout the whole FOV, using a
Fourth workshop on experiments and detectors for a relativistic heavy ion collider
International Nuclear Information System (INIS)
Fatyga, M.; Moskowitz, B.
1990-01-01
This report contains papers on the following topics: physics at RHIC; flavor flow from quark-gluon plasma; space-time quark-gluon cascade; jets in relativistic heavy ion collisions; parton distributions in hard nuclear collisions; experimental working groups, two-arm electron/photon spectrometer collaboration; total and elastic pp cross sections; a 4π tracking TPC magnetic spectrometer; hadron spectroscopy; efficiency and background simulations for J/ψ detection in the RHIC dimuon experiment; the collision regions beam crossing geometries; Monte Carlo simulations of interactions and detectors; proton-nucleus interactions; the physics of strong electromagnetic fields in collisions of relativistic heavy ions; a real time expert system for experimental high energy/nuclear physics; the development of silicon multiplicity detectors; a pad readout detector for CRID/tracking; RHIC TPC R ampersand D progress and goals; development of analog memories for RHIC detector front-end electronic systems; calorimeter/absorber optimization for a RHIC dimuon experiment; construction of a highly segmented high resolution TOF system; progress report on a fast, particle-identifying trigger based on ring-imaging and highly integrated electronics for a TPC detector
Fourth workshop on experiments and detectors for a relativistic heavy ion collider
Energy Technology Data Exchange (ETDEWEB)
Fatyga, M.; Moskowitz, B. (eds.)
1990-01-01
This report contains papers on the following topics: physics at RHIC; flavor flow from quark-gluon plasma; space-time quark-gluon cascade; jets in relativistic heavy ion collisions; parton distributions in hard nuclear collisions; experimental working groups, two-arm electron/photon spectrometer collaboration; total and elastic pp cross sections; a 4{pi} tracking TPC magnetic spectrometer; hadron spectroscopy; efficiency and background simulations for J/{psi} detection in the RHIC dimuon experiment; the collision regions beam crossing geometries; Monte Carlo simulations of interactions and detectors; proton-nucleus interactions; the physics of strong electromagnetic fields in collisions of relativistic heavy ions; a real time expert system for experimental high energy/nuclear physics; the development of silicon multiplicity detectors; a pad readout detector for CRID/tracking; RHIC TPC R D progress and goals; development of analog memories for RHIC detector front-end electronic systems; calorimeter/absorber optimization for a RHIC dimuon experiment; construction of a highly segmented high resolution TOF system; progress report on a fast, particle-identifying trigger based on ring-imaging and highly integrated electronics for a TPC detector.
A novel enhanced calibration method for DSSSD detectors
Energy Technology Data Exchange (ETDEWEB)
Kaya, Levent; Vogt, Andreas; Reiter, Peter; Birkenbach, Benedikt; Hirsch, Rouven; Seidlitz, Michael; Warr, Nigel [Institut fuer Kernphysik, Universitaet zu Koeln (Germany)
2016-07-01
Double-sided silicon strip detectors (DSSSD) are employed for the detection of charged particles in low-energy nuclear physics providing position and energy information for the impinging particle. Intersecting areas of both p- and n-side strips form individual pixel segments allowing for a high detector granularity. However, due to limitation in fabrication and the response of readout electronics, the performance of different channels may vary. In order to achieve best energy information, a calibration of each p- and n-side strip with a very high precision is mandatory. DSSSD responses are analyzed employing energy correlation matrices between adjacent strips in order to determine charge-sharing and energy-loss effects. A novel calibration method is based on the fact that each event is registered simultaneously on the p- and n-side strips. A two-dimensional calibration procedure allows for a significant enhancement of the energy resolution. In this way, the performance of DSSSDs with position-dependent radiation damage is improved clearly by excluding locally damaged detector areas without losing the information of complete p- or n-side strips.
Calibration and Characterization of the UNCB and Nab Detectors
Zeck, Bryan; UCNB Collaboration; Nab Collaboration
2017-09-01
The UCNB and Nab experiments are designed to produce precision measurements of the free neutron decay angular correlations B, a, and b. Measurements of B and a require a coincident detection of the proton and electron produced in neutron decay, while for b, which manifests as a subtle shift in the electron energy spectrum, energy resolution better than 3 keV is desired and excellent fidelity for energy reconstruction is required, including characterization of non-linearity to the 10-4 level. To this end, a thick segmented silicon detector with a 100 nm dead layer and a 100 cm active area has been extensively characterized at LANL. The thin dead layer allows protons accelerated to 30 keV to deposit energy above threshold in the active volume of the detector, and the paired amplifer chain, developed at LANL, has a risetime of approximately 40 ns. Comparison of simulation to experiment reveals a detector resolution better than σ = 2.5 keV. A complete characterization of the detector will be presented. This work has been supported by Grants from the US National Science Foundation and the Department of Energy.
International Nuclear Information System (INIS)
Swoboda, C.; Barsotti, E.; Chappa, S.; Downing, R.; Goeransson, G.; Lensy, D.; Moore, G.; Rotolo, C.; Urish, J.
1985-01-01
The FASTBUS Segment Interconnect (SI) provides a communication path between two otherwise independent, asynchronous bus segments. In particular, the Segment Interconnect links a backplane crate segment to a cable segment. All standard FASTBUS address and data transactions can be passed through the SI or any number of SIs and segments in a path. Thus systems of arbitrary connection complexity can be formed, allowing simultaneous independent processing, yet still permitting devices associated with one segment to be accessed from others. The model S1 Segment Interconnect and the Cable Segment Ancillary Logic covered in this report comply with all the mandatory features stated in the FASTBUS specification document DOE/ER-0189. A block diagram of the SI is shown
Heavy Ion Physics Prospects with the ATLAS Detector at the LHC
Grau, N
2008-01-01
The next great energy frontier in Relativistic Heavy Ion Collisions is quickly approaching with the completion of the Large Hadron Collider and the ATLAS experiment is poised to make important contributions in understanding QCD matter at extreme conditions. While designed for high-pT measurements in high-energy p+p collisions, the detector is well suited to study many aspects of heavy ion collisions from bulk phenomena to high-pT and heavy flavor physics. With its large and finely segmented electromagnetic and hadronic calorimeters, the ATLAS detector excels in measurements of photons and jets, observables of great interest at the LHC. In this talk, we highlight the performance of the ATLAS detector for Pb+Pb collisions at the LHC with special emphasis on a key feature of the ATLAS physics program: jet and direct photon measurements.
Cardiac imaging using 256-detector row four-dimensional CT. Preliminary clinical report
International Nuclear Information System (INIS)
Kido, Teruhito; Kurata, Akira; Higashino, Hiroshi
2007-01-01
Along with the increase of detector rows on the z-axis and a faster gantry rotation speed, the spatial and temporal resolutions of the multislice computed tomography (CT) have been improved for noninvasive coronary artery imaging. We investigated the feasibility of the second specification prototype 256-detector row four-dimensional CT for assessing coronary artery and cardiac function. The subjects were five patients with coronary artery disease. Contrast medium (40-60 ml) was intravenously administered at the rate of 3-4 ml/s. The patient's whole heart was scanned for 1.5 s to cover at least one cardiac cycle during breathholding without electrocardiographic gating. Parameters used were 0.5 mm slice thickness, 0.5 s/rotation, 120 Kv, and 350 mA, with a half-scan reconstruction algorithm (temporal resolution 250 ms). Twenty-six transaxial datasets were reconstructed at intervals of 50 ms. The assessability of the coronary arteries in American Heart Association (AHA) segments 1, 2, 3, 5, 6, 7, 9, and 11 was visually evaluated, resulting in 29 of 32 (90.9%) segments being assessable. Functional assessment was also performed using animated movies without banding artifacts in all cases. The 256-detector row four-dimensional CT can assess the coronary artery and cardiac function using data during 1.5 s without banding artifacts. (author)
Development and characterization of micro-pattern gas detectors for intense beams of hadrons
Energy Technology Data Exchange (ETDEWEB)
Vandenbroucke, Maxence
2012-07-02
This thesis work is dedicated to the design, development and characterization of Micro-Pattern Gas Detectors. The performances of a Time Projection Chamber (TPC) equipped with a triple Gas Electron Multiplier (GEM) amplification structure are reported. The intrinsic ion backflow suppression of GEM foils drastically reduces the space charge produced by wire readout in traditional TPC. The GEM solution allows the operation of a TPC at much higher event rate. The second part of this thesis describes the development of a 40 x 40 cm{sup 2} Micromegas detector with a highly segmented central area. A reduction of discharges compared to conventional Micromegas detectors is needed for stable operation in intense beams of hadrons. Spark reduction technologies have been successfully studied and results are presented.
Development and characterization of micro-pattern gas detectors for intense beams of hadrons
International Nuclear Information System (INIS)
Vandenbroucke, Maxence
2012-01-01
This thesis work is dedicated to the design, development and characterization of Micro-Pattern Gas Detectors. The performances of a Time Projection Chamber (TPC) equipped with a triple Gas Electron Multiplier (GEM) amplification structure are reported. The intrinsic ion backflow suppression of GEM foils drastically reduces the space charge produced by wire readout in traditional TPC. The GEM solution allows the operation of a TPC at much higher event rate. The second part of this thesis describes the development of a 40 x 40 cm 2 Micromegas detector with a highly segmented central area. A reduction of discharges compared to conventional Micromegas detectors is needed for stable operation in intense beams of hadrons. Spark reduction technologies have been successfully studied and results are presented.
Semiconductor Pixel detectors and their applications in life sciences
International Nuclear Information System (INIS)
Jakubek, J
2009-01-01
Recent advances in semiconductor technology allow construction of highly efficient and low noise pixel detectors of ionizing radiation. Steadily improving quality of front end electronics enables fast digital signal processing in each pixel which offers recording of more complete information about each detected quantum (energy, time, number of particles). All these features improve an extend applicability of pixel technology in different fields. Some applications of this technology especially for imaging in life sciences will be shown (energy and phase sensitive X-ray radiography and tomography, radiography with heavy charged particles, neutron radiography, etc). On the other hand a number of obstacles can limit the detector performance if not handled. The pixel detector is in fact an array of individual detectors (pixels), each of them has its own efficiency, energy calibration and also noise. The common effort is to make all these parameters uniform for all pixels. However an ideal uniformity can be never reached. Moreover, it is often seen that the signal in one pixel can affect the neighbouring pixels due to various reasons (e.g. charge sharing). All such effects have to be taken into account during data processing to avoid false data interpretation. A brief view into the future of pixel detectors and their applications including also spectroscopy, tracking and dosimetry is given too. Special attention is paid to the problem of detector segmentation in context of the charge sharing effect.
Status of the development of a HPGe-BGO pair spectrometer for ELI-NP
Energy Technology Data Exchange (ETDEWEB)
Homm, Ilja; Ignatov, Alexander; Ilieva, Stoyanka; Kroell, Thorsten [Technische Universitaet Darmstadt, Darmstadt (Germany)
2016-07-01
At the moment, the new European research facility called ELI-NP (The Extreme Light Infrastructure - Nuclear Physics) is being built in Bucharest-Magurele, Romania. It is one of three parts of the ELI project and offers applications for the investigation of questions concerning nuclear physics. The 8 HPGe (High-Purity Germanium) CLOVER detectors of ELIADE (ELI-NP Array of DEtectors) with four crystals each and high resolution are important components for the gamma spectroscopic study of photonuclear reactions. These detectors are surrounded by standard anti-Compton shields (AC shield). We investigate the possibility to operate for two of the ELIADE CLOVERS an advanced version of an AC shield as escape γ-rays pair spectrometers to extend the high-resolution spectroscopy to photon energies of several MeV where the pair production process dominates. The main tasks in this work are to develop and test such an AC shield: a pair spectrometer with BGO and CsI(Tl) crystals with APD (avalanche photodiode) or SPM (silicon photomultiplier) readout. The results of prototype testing are reported.
A new strips tracker for the upgraded ATLAS ITk detector
David, C.
2018-01-01
The ATLAS detector has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the next-generation tracking detector proposed for the High Luminosity LHC (HL-LHC), the so-called ATLAS Phase-II Upgrade, the fluences and radiation levels will be higher by as much as a factor of ten. The new sub-detectors must thus be faster, of larger area, more segmented and more radiation hard while the amount of inactive material should be minimized and the power supply to the front-end systems should be increased. For those reasons, the current inner tracker of the ATLAS detector will be fully replaced by an all-silicon tracking system that consists of a pixel detector at small radius close to the beam line and a large area strip tracker surrounding it. This document gives an overview of the design of the strip inner tracker (Strip ITk) and summarises the intensive R&D activities performed over the last years by the numerous institutes within the Strips ITk collaboration. These studies are accompanied with a strong prototyping effort to contribute to the optimisation of the Strip ITk's structure and components. This effort culminated recently in the release of the ATLAS Strips ITk Technical Design Report (TDR).
Segmented block copolymers with monodisperse aramide end-segments
Araichimani, A.; Gaymans, R.J.
2008-01-01
Segmented block copolymers were synthesized using monodisperse diaramide (TT) as hard segments and PTMO with a molecular weight of 2 900 g · mol-1 as soft segments. The aramide: PTMO segment ratio was increased from 1:1 to 2:1 thereby changing the structure from a high molecular weight multi-block
Segmentation of consumer's markets and evaluation of market's segments
ŠVECOVÁ, Iveta
2013-01-01
The goal of this bachelor thesis was to explain a possibly segmentation of consumer´s markets for a chosen company, and to present a suitable goods offer, so it would be suitable to the needs of selected segments. The work is divided into theoretical and practical part. First part describes marketing, segmentation, segmentation of consumer's markets, consumer's market, market's segments a other terms. Second part describes an evaluation of questionnaire survey, discovering of market's segment...
Improved performances of CsI(Tl) scintillation detectors for DIAMANT II multidetector
International Nuclear Information System (INIS)
Scheurer, J-N.; Virassamynaiken, E.; Kalinka, G.; Nyako, B.M.; Gal, J.
1997-01-01
The scintillation detectors used for light particle discrimination require a careful optimization of performances of the scintillator-light guide assembly to ensure a good light channeling to photodiode. To obtain a good energy resolution and a good peak symmetry such an optimization has been carried out on the 'Chess-Board' detectors consisting of 25 units, a system which is to be utilised as additional detector at EUROBALL. Recently, such optimization has been realised also for the detectors of the DIAMANT II assembly. This multidetector includes the 'Chess-Board' and constitutes a more segmented version of DIAMANT with 82 detectors instead of 54 detectors. The ensemble of these charged light particle detectors is to be incorporated in EUROBALL. For the first newly conditioned 34 detectors the light collection and the energy resolution measured for 5.5 MeV α particles equal 70 ± 3% and 2.4 ± 0.2%, respectively. The best result was obtained with 232 U as a α particle source and using a 6 μs time constant amplifier. The line shape of the spectrum peaks can be described by the function 1/(E 0 - E) 1-α convoluted with Lorentz and Gauss functions. For the peak of 8.7 MeV, measured with the CsI (Tl) detector, the asymmetry is as low as α 0.02 while the Gaussian and Lorentzian widths are given by 2 Γ/E 0 0.005 and 2.35 σ/E 0 = 0.019
Development of Ge/NbSi detectors for EDELWEISS-II with identification of near-surface events
International Nuclear Information System (INIS)
Juillard, A.; Marnieros, S.; Dolgorouky, Y.; Berge, L.; Collin, S.; Fiorucci, S.; Lalu, F.; Dumoulin, L.
2006-01-01
The actual limitation of Ge ionization heat cryogenic detectors for direct WIMP detection such as EDELWEISS arises from incomplete charge collection for near-surface events. We present results on Ge/NbSi detectors that are fitted with segmented electrodes and two NbSi Anderson insulator thermometric layers. Three such bolometers were studied in the low-background cryostat of the EDELWEISS collaboration in the LSM: analysis of the athermal signals allows us to identify and reject events occurring in the first millimeter under the electrodes
Development of Ge/NbSi detectors for EDELWEISS-II with identification of near-surface events
Energy Technology Data Exchange (ETDEWEB)
Juillard, A. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3/CNRS, Bat 108, Orsay Campus 91405 (France)]. E-mail: juillard@csnsm.in2p3.fr; Marnieros, S. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3/CNRS, Bat 108, Orsay Campus 91405 (France); Dolgorouky, Y. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3/CNRS, Bat 108, Orsay Campus 91405 (France); Berge, L. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3/CNRS, Bat 108, Orsay Campus 91405 (France); Collin, S. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3/CNRS, Bat 108, Orsay Campus 91405 (France); Fiorucci, S. [C.E.A, Centre d' etudes Nucleaires de Saclay, DSM/DAPNIA, Gif. Yvette, Cedex 91191n (France); Lalu, F. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3/CNRS, Bat 108, Orsay Campus 91405 (France); Dumoulin, L. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), IN2P3/CNRS, Bat 108, Orsay Campus 91405 (France)
2006-04-15
The actual limitation of Ge ionization heat cryogenic detectors for direct WIMP detection such as EDELWEISS arises from incomplete charge collection for near-surface events. We present results on Ge/NbSi detectors that are fitted with segmented electrodes and two NbSi Anderson insulator thermometric layers. Three such bolometers were studied in the low-background cryostat of the EDELWEISS collaboration in the LSM: analysis of the athermal signals allows us to identify and reject events occurring in the first millimeter under the electrodes.
Cryo-EM Structure Determination Using Segmented Helical Image Reconstruction.
Fromm, S A; Sachse, C
2016-01-01
Treating helices as single-particle-like segments followed by helical image reconstruction has become the method of choice for high-resolution structure determination of well-ordered helical viruses as well as flexible filaments. In this review, we will illustrate how the combination of latest hardware developments with optimized image processing routines have led to a series of near-atomic resolution structures of helical assemblies. Originally, the treatment of helices as a sequence of segments followed by Fourier-Bessel reconstruction revealed the potential to determine near-atomic resolution structures from helical specimens. In the meantime, real-space image processing of helices in a stack of single particles was developed and enabled the structure determination of specimens that resisted classical Fourier helical reconstruction and also facilitated high-resolution structure determination. Despite the progress in real-space analysis, the combination of Fourier and real-space processing is still commonly used to better estimate the symmetry parameters as the imposition of the correct helical symmetry is essential for high-resolution structure determination. Recent hardware advancement by the introduction of direct electron detectors has significantly enhanced the image quality and together with improved image processing procedures has made segmented helical reconstruction a very productive cryo-EM structure determination method. © 2016 Elsevier Inc. All rights reserved.
The Belle II imaging Time-of-Propagation (iTOP) detector
Fast, J.; Belle II Barrel Particle Identification Group
2017-12-01
High precision flavor physics measurements are an essential complement to the direct searches for new physics at the LHC ATLAS and CMS experiments. Such measurements will be performed using the upgraded Belle II detector that will take data at the SuperKEKB accelerator. With 40x the luminosity of KEKB, the detector systems must operate efficiently at much higher rates than the original Belle detector. A central element of the upgrade is the barrel particle identification system. Belle II has built and installed an imaging-Time-of-Propagation (iTOP) detector. The iTOP uses quartz optics as Cherenkov radiators. The photons are transported down the quartz bars via total internal reflection with a spherical mirror at the forward end to reflect photons to the backward end where they are imaged onto an array of segmented Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMTs). The system is read out using giga-samples per second waveform sampling Application-Specific Integrated Circuits (ASICs). The combined timing and spatial distribution of the photons for each event are used to determine particle species. This paper provides an overview of the iTOP system.
International Nuclear Information System (INIS)
Bergmann, B.; Caicedo, I.; Pospisil, S.; Vykydal, Z.; Leroy, C.
2016-01-01
A two-layer pixel detector setup (ATLAS-TPX), designed for thermal and fast neutron detection and radiation field characterization is presented. It consists of two segmented silicon detectors (256 × 256 pixels, pixel pitch 55 μm, thicknesses 300 μm and 500 μm) facing each other. To enhance the neutron detection efficiency a set of converter layers is inserted in between these detectors. The pixelation and the two-layer design allow a discrimination of neutrons against γs by pattern recognition and against charged particles by using the coincidence and anticoincidence information. The neutron conversion and detection efficiencies are measured in a thermal neutron field and fast neutron fields with energies up to 600 MeV. A Geant4 simulation model is presented, which is validated against the measured detector responses. The reliability of the coincidence and anticoincidence technique is demonstrated and possible applications of the detector setup are briefly outlined.
The enzyme polyphenol oxidase (PPO) reduces the extent of proteolysis and lipolysis within red clover fed to ruminants. PPO catalyses the conversion of phenols to quinones which can react with nucleophilic cellular constituents (e.g. proteins), forming protein-phenol complexes that may reduce protei...
Resolving overlaping gammas in a modular neutrals detector
International Nuclear Information System (INIS)
Bulos, F.
1975-01-01
It is shown that in a segmented neutral detector the method of moments can be used to determine whether a connected region of energy deposit involving several modules contains one, two, or more γ's. Up to 2 γ's can be handled analytically to solve for their energy and position. Further it is shown that if the positions of the γ's are determined externally, then the method of moments can be used to solve the problem of more than 2 γ's analytically
Energy Technology Data Exchange (ETDEWEB)
Abdel Sabour, M.F.; El-Naggar, H.A.; Soliman, S.M. (Atomic Energy Establishment, Cairo (Egypt). Nuclear Chemistry Dept.)
1991-01-01
Outdoor lysimeter experiments were carried out to elucidate the effect of 4 inorganic and 3 organic salts on {sup 60}Co and {sup 134}Cs uptake and dry matter yield of three cuts of clover in the soils of Inshas. A new concept was proposed for assessing the difference in capacity of soil to supply radionuclides to plants as affected by applied inorganic or organic compounds. A relation of plant tissue radionuclide content with time can be expressed in an exponential equation with corresponding regression coefficients. When the same plant species is grown on the same soil differing only in the applied compounds (e.g. Fe-EDDHA, Fe-DTPA, Fe-OAC, Fe(COO){sub 2}, Al(OH){sub 3}, Ca(H{sub 2}PO{sub 4}){sub 2}, Fe{sub 2}O{sub 3}) the derived equation will change. Differences of either Co or Cs accumulation with time between control and any other treatment were evaluated. The data also show that Fe-DTPA is preferred for {sup 60}Co as enhancing compound for plant uptake (for decontamination use), compared with other applied salts, on the other hand, any tested salts did not significantly effect {sup 134}Cs taken by clover. It was also found that more than 70% of the total cobalt uptake was accumulated in the roots which indicate that Co is less mobile in plants than Cs. (orig.).
International Nuclear Information System (INIS)
Abdel Sabour, M.F.; El-Naggar, H.A.; Soliman, S.M.
1991-01-01
Outdoor lysimeter experiments were carried out to elucidate the effect of 4 inorganic and 3 organic salts on 60 Co and 134 Cs uptake and dry matter yield of three cuts of clover in the soils of Inshas. A new concept was proposed for assessing the difference in capacity of soil to supply radionuclides to plants as affected by applied inorganic or organic compounds. A relation of plant tissue radionuclide content with time can be expressed in an exponential equation with corresponding regression coefficients. When the same plant species is grown on the same soil differing only in the applied compounds (e.g. Fe-EDDHA, Fe-DTPA, Fe-OAC, Fe(COO) 2 , Al(OH) 3 , Ca(H 2 PO 4 ) 2 , Fe 2 O 3 ) the derived equation will change. Differences of either Co or Cs accumulation with time between control and any other treatment were evaluated. The data also show that Fe-DTPA is preferred for 60 Co as enhancing compound for plant uptake (for decontamination use), compared with other applied salts, on the other hand, any tested salts did not significantly effect 134 Cs taken by clover. It was also found that more than 70% of the total cobalt uptake was accumulated in the roots which indicate that Co is less mobile in plants than Cs. (orig.) [de
Reaction of cocksfoot (Dactylis glomerata L. in grass-clover mixture on N fertilization and grazing
Directory of Open Access Journals (Sweden)
Marcela Andreata-Koren
2009-09-01
Full Text Available Grazing is the most common way of using a hill and mountain areas because of their specific agro-ecological conditions. Cocksfoot is a grass with high productivity and quality, and it is very good for sowing in the sward for grazing. Because of its good adaptability to different growing conditions, especially in very dry and cold areas, it is excellent in relation to some other good grasses, which can not be raised in such areas. The aim of the experiment was to determine effect of N application (0-N0 and 150 kg ha-1 year-1-N150 and rotational grazing by cattle (C and sheep (S, and their interaction on the cocksfoot sown in a mixture of smooth-stalked meadow grass (Poa pratensis L. and white clover (Trifolium repens L. in hill mountain areas. In a three-year average, the application of 150 kg ha-1 N had significant impact on cocksfoot population density (number of tillers m-2, and it was 51.4 % higher than the recorded one before grazing (P<0.05 and 42.2 % higher after grazing (P<0.01 in comparison to N0. The application of 150 kg ha-1 N resulted in significantly higher cocksfoot dry matter (DM yield for 38.6 % (P<0.01 and 15.3 % higher cocksfoot share in the total mixture in relation to N0 (P<0.01. Grazing management and grazing management interaction with N rate did not significantly affect the population density of individual years. However, in the three-year average, grazing management significantly affected cocksfoot DM (P<0.01 and its percentage in the total DM mixture (P<0.01. Cattle grazing resulted in 9.9 % higher cocksfoot DM yield and 15.2 % higher cocksfoot percentage in pasture. Interaction of grazing management and N-level had significant influence on the percentage of cocksfoot DM in grass-clover mixture. On cattle grazed areas fertilized with 150 kg ha-1 N, the percentage of cocksfoot DM was the highest (74. 07%, while the lowest percentage of cocksfoot DM was recorded on the sheep grazed areas without N (55.12%.
Sun, Hao; Xue, Hua-dan; Jin, Zheng-yu; Wang, Xuan; Chen, Yu; He, Yong-lan; Zhang, Da-ming; Zhu, Liang; Wang, Yun; Qi, Bing; Xu, Kai; Wang, Ming
2014-10-01
To retrospectively evaluate the clinical feasibility of high-pitch excretory phase images during dual-source CT urography with Stellar photon detector. Totally 100 patients received dual-source CT high-pitch urinary excretory phase scanning with Stellar photon detector [80 kV, ref.92 mAs, CARE Dose 4D and CARE kV, pitch of 3.0, filter back projection reconstruction algorithm (FBP)] (group A). Another 100 patients received dual-source CT high-pitch urinary excretory phase scanning with common detector(100 kV, ref.140 mAs, CARE Dose 4D, pitch of 3.0, FBP) (group B). Quantitative measurement of CT value of urinary segments (Hounsfield units), image noise (Hounsfield units), and effective radiation dose (millisievert) were compared using independent-samples t test between two groups. Urinary system subjective opacification scores were compared using Mann-Whitney U test between two groups. There was no significant difference in subjective opacification score of intrarenal collecting system and ureters between two groups (all P>0.05). The group A images yielded significantly higher CT values of all urinary segments (all P0.05). The effective radiation dose of group A (1.1 mSv) was significantly lower than that of group B (3.79 mSv) (Ppitch low-tube-voltage during excretory phase dual-source CT urography with Stellar photon detector is feasible, with acceptable image noise and lower radiation dose.
Awad, George M.
2007-01-01
This dissertation describes new techniques that can be used in a sign language recognition (SLR) system, and more generally in human gesture systems. Any SLR system consists of three main components: Skin detector, Tracker, and Recognizer. The skin detector is responsible for segmenting skin objects like the face and hands from video frames. The tracker keeps track of the hand location (more specifically the bounding box) and detects any occlusions that might happen between any skin objects. ...
International Nuclear Information System (INIS)
Schlosser, T.; Mohrs, O.K.; Magedanz, A.; Nowak, B.; Voigtlaender, T.; Barkhausen, J.; Schmermund, A.
2007-01-01
Purpose: To evaluate the value of 64-detector-row computed tomography for ruling out high-grade coronary stenoses in patients with a low to moderate pretest probability of significant coronary artery disease. Material and Methods: The study included 61 patients with a suspicion of coronary artery disease on the basis of atypical angina or ambiguous findings in noninvasive stress testing and a class II indication for invasive coronary angiography (ICA). All patients were examined by 64-detector-row computed tomography angiography (CTA) and ICA. On a coronary segmental level, the presence of significant (>50% diameter) stenoses was examined. Results: In a total of 915 segments, CTA detected 62 significant stenoses. Thirty-four significant stenoses were confirmed by ICA, whereas 28 stenoses could not be confirmed by ICA. Twenty-two of them showed wall irregularities on ICA, and six were angiographically normal. Accordingly, on a coronary segmental basis, 28 false-positive and 0 false-negative findings resulted in a sensitivity of 100%, a specificity of 96.8%, a positive predictive value of 54.8%, and a negative predictive value of 100%. The diagnostic accuracy was 96.9%. Conclusion: Sixty-four-detector-row computed tomography reliably detects significant coronary stenoses in patients with suspected coronary artery disease and appears to be helpful in the selection of patients who need to undergo ICA. Calcified and non-calcified plaques are detected. Grading of stenoses in areas with calcification is difficult. Frequently, stenosis severity is overestimated by 64-detector-row computed tomography
Energy Technology Data Exchange (ETDEWEB)
Schlosser, T.; Mohrs, O.K.; Magedanz, A.; Nowak, B.; Voigtlaender, T.; Barkhausen, J.; Schmermund, A. [Dept. of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen (Germany)
2007-04-15
Purpose: To evaluate the value of 64-detector-row computed tomography for ruling out high-grade coronary stenoses in patients with a low to moderate pretest probability of significant coronary artery disease. Material and Methods: The study included 61 patients with a suspicion of coronary artery disease on the basis of atypical angina or ambiguous findings in noninvasive stress testing and a class II indication for invasive coronary angiography (ICA). All patients were examined by 64-detector-row computed tomography angiography (CTA) and ICA. On a coronary segmental level, the presence of significant (>50% diameter) stenoses was examined. Results: In a total of 915 segments, CTA detected 62 significant stenoses. Thirty-four significant stenoses were confirmed by ICA, whereas 28 stenoses could not be confirmed by ICA. Twenty-two of them showed wall irregularities on ICA, and six were angiographically normal. Accordingly, on a coronary segmental basis, 28 false-positive and 0 false-negative findings resulted in a sensitivity of 100%, a specificity of 96.8%, a positive predictive value of 54.8%, and a negative predictive value of 100%. The diagnostic accuracy was 96.9%. Conclusion: Sixty-four-detector-row computed tomography reliably detects significant coronary stenoses in patients with suspected coronary artery disease and appears to be helpful in the selection of patients who need to undergo ICA. Calcified and non-calcified plaques are detected. Grading of stenoses in areas with calcification is difficult. Frequently, stenosis severity is overestimated by 64-detector-row computed tomography.
Integrated readout of organic scintillator and ZnS:Ag/6LiF for segmented antineutrino detectors
International Nuclear Information System (INIS)
Kiff, Scott D.; Reyna, David; Monahan, James; Bowden, Nathaniel S.
2010-01-01
Antineutrino detection using inverse beta decay conversion has demonstrated the capability to measure nuclear reactor power and fissile material content for nuclear safeguards. Current efforts focus on aboveground deployment scenarios, for which highly efficient capture and identification of neutrons is needed to measure the anticipated antineutrino event rates in an elevated background environment. In this submission, we report on initial characterization of a new scintillation-based segmented design that uses layers of ZnS:Ag/ 6 LiF and an integrated readout technique to capture and identify neutrons created in the inverse beta decay reaction. Laboratory studies with multiple organic scintillator and ZnS:Ag/ 6 LiF configurations reliably identify 6 Li neutron captures in 60 cm-long segments using pulse shape discrimination.
International Nuclear Information System (INIS)
Volynets, Oleksandr
2012-01-01
Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.
Energy Technology Data Exchange (ETDEWEB)
Volynets, Oleksandr
2012-07-27
Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.
A fast readout system for scintillation detectors
International Nuclear Information System (INIS)
Steijger, J.; Kok, E.; Kwakkel, E.; Visschers, J.L.; Zwart, A.N.M.
1991-01-01
A system of fast readout electronics for segmented scintillation detectors has been constructed and is now operational. Instead of delaying the analog signals in long coaxial cables, they are digitized immediately and stored in dual-port memories, while the trigger decision is being made. A VMEbus system collects the data from these memories on the data acquisition modules within one crate. Several VME crates are connected via a transputer network to transport the data to an event builder. A separate transputer network is used to perform the VME cycles, needed for the computer-controlled tuning of the experiment. (orig.)
Unifying Terrain Awareness for the Visually Impaired through Real-Time Semantic Segmentation
Directory of Open Access Journals (Sweden)
Kailun Yang
2018-05-01
Full Text Available Navigational assistance aims to help visually-impaired people to ambulate the environment safely and independently. This topic becomes challenging as it requires detecting a wide variety of scenes to provide higher level assistive awareness. Vision-based technologies with monocular detectors or depth sensors have sprung up within several years of research. These separate approaches have achieved remarkable results with relatively low processing time and have improved the mobility of impaired people to a large extent. However, running all detectors jointly increases the latency and burdens the computational resources. In this paper, we put forward seizing pixel-wise semantic segmentation to cover navigation-related perception needs in a unified way. This is critical not only for the terrain awareness regarding traversable areas, sidewalks, stairs and water hazards, but also for the avoidance of short-range obstacles, fast-approaching pedestrians and vehicles. The core of our unification proposal is a deep architecture, aimed at attaining efficient semantic understanding. We have integrated the approach in a wearable navigation system by incorporating robust depth segmentation. A comprehensive set of experiments prove the qualified accuracy over state-of-the-art methods while maintaining real-time speed. We also present a closed-loop field test involving real visually-impaired users, demonstrating the effectivity and versatility of the assistive framework.
One half of the central detector for the Axial Field Spectrometer (AFS)experiment R807
CERN PhotoLab
1979-01-01
This experiment was setup at the ISR intersection I-8 by the Brookhaven-CERN-Copenhagen-Lund-Rutherford Lab.-Tel Aviv Collaboration to study large transverse momentum phenomena (see Annual Report 1979 p. 69). The central detector (here shown for a part) was a cylindrical drift chamber with fine azimuthal segmentation.
Yong, Bin; Xie, Huan; Li, Zhou; Li, Ya-Ping; Zhang, Yan; Nie, Gang; Zhang, Xin-Quan; Ma, Xiao; Huang, Lin-Kai; Yan, Yan-Hong; Peng, Yan
2017-01-01
In order to investigate the physiological effects of exogenous γ-aminobutyric acid (GABA) on drought tolerance in white clover (Trifolium repens), GABA shunt, polyamines (PAs), and proline (Pro) metabolism were examined after plants pretreated with or without GABA (8 mM) and then exposed to water or 15% PEG-induced drought stress in growth chamber. In this study, exogenous application of GABA effectively alleviated drought-induced damage in leaves, as reflected by significantly higher relative water content, lower electrolyte leakage, lipid peroxidation, and leaf wilt. Exogenous GABA further promoted drought-induced increases in GABA transaminase and alpha ketone glutarate dehydrogenase activities, but inhibited glutamate decarboxylase activity under both control and drought conditions, resulting in an increase in endogenous glutamate (Glu) and GABA content. Besides, exogenous GABA could well accelerated PAs synthesis and suppressed PAs catabolism, which lead to the extremely enhanced different types of PAs content (free Put and Spd, insoluble bound Spd and Spm, soluble conjugated Spd and Spm, and total Put, Spd and Spm) under drought stress. In addition, exogenous GABA application further activated drought-induced Δ 1 -pyrroline-5-carboxylate synthetase and proline dehydrogenase activities, but suppressed drought-facilitated ornithine -δ-amino transferase activities, leading to a higher Pro accumulation and metabolism in GABA-pretreated plants in the middle and last period of drought. The results suggested that increased endogenous GABA by exogenous GABA treatment could improve drought tolerance of white clover associated with a positive regulation in the GABA-shunt, PAs and Pro metabolism.
Detector simulation needs for detector designers
International Nuclear Information System (INIS)
Hanson, G.G.
1987-11-01
Computer simulation of the components of SSC detectors and of the complete detectors will be very important for the designs of the detectors. The ratio of events from interesting physics to events from background processes is very low, so detailed understanding of detector response to the backgrounds is needed. Any large detector for the SSC will be very complex and expensive and every effort must be made to design detectors which will have excellent performance and will not have to undergo major rebuilding. Some areas in which computer simulation is particularly needed are pattern recognition in tracking detectors and development of shower simulation code which can be trusted as an aid in the design and optimization of calorimeters, including their electron identification performance. Existing codes require too much computer time to be practical and need to be compared with test beam data at energies of several hundred GeV. Computer simulation of the processing of the data, including electronics response to the signals from the detector components, processing of the data by microprocessors on the detector, the trigger, and data acquisition will be required. In this report we discuss the detector simulation needs for detector designers
International Nuclear Information System (INIS)
Atkinson, Charlotte; Warren, Ruth ML; Sala, Evis; Dowsett, Mitch; Dunning, Alison M; Healey, Catherine S; Runswick, Shirley; Day, Nicholas E; Bingham, Sheila A
2004-01-01
Isoflavones are hypothesized to protect against breast cancer, but it is not clear whether they act as oestrogens or anti-oestrogens in breast tissue. Our aim was to determine the effects of taking a red clover-derived isoflavone supplement daily for 1 year on mammographic breast density. Effects on oestradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), lymphocyte tyrosine kinase activity and menopausal symptoms were also assessed. A total of 205 women (age range 49–65 years) with Wolfe P2 or DY mammographic breast patterns were randomly assigned to receive either a red clover-derived isoflavone tablet (26 mg biochanin A, 16 mg formononetin, 1 mg genistein and 0.5 mg daidzein) or placebo. Change in mammographic breast density, serum oestradiol, FSH, LH, menopausal symptoms and lymphocyte tyrosine kinase activity from baseline to 12 months were assessed. A total of 177 women completed the trial. Mammographic breast density decreased in both groups but the difference between the treatment and placebo was not statistically significant. There was a significant interaction between treatment group and oestrogen receptor (ESR1) PvuII polymorphism for the change in estimated percentage breast density (mean ± standard deviation): TT isoflavone 1.4 ± 12.3% and TT placebo -9.6 ± 14.2%; CT isoflavone -5.2 ± 12.0% and CT placebo -2.8 ± 10.3%; and CC isoflavone -3.4 ± 9.7% and CC placebo -1.1 ± 9.5%. There were no statistically significant treatment effects on oestradiol, FSH, or LH (assessed only in postmenopausal women), or on lymphocyte tyrosine kinase activity. Baseline levels of menopausal symptoms were low, and there were no statistically significant treatment effects on frequency of hot flushes or other menopausal symptoms. In contrast to studies showing that conventional hormone replacement therapies increase mammographic breast density, the isoflavone supplement did not increase mammographic breast density in this population of women
Elemental analysis and nutritional value of edible Trifolium (clover) species.
Gounden, Thaveshan; Moodley, Roshila; Jonnalagadda, Sreekantha B
2018-04-30
Trifolium species, commonly known as clover species, have a cosmopolitan distribution and, as such, are used in many different traditional systems of medicine and consumed by many communities all over the world. In this study, the elemental distribution and nutritional value of five edible Trifolium species, namely, Trifolium africanum, Trifolium burchellianum, Trifolium repens, Trifolium dubium and Trifolium pratense were investigated to evaluate the potential of these plant species to alleviate malnutrition, thereby contributing toward the fight against food insecurity. Trifolium species were found to be a rich alternate source of essential nutrients with concentrations of elements being in decreasing order of Ca > Mg > Fe > Mn > Zn > Se > Cu > Cr > Pb > Ni > Co > Cd > As and with adequate levels of lipids (4.2 to 8.6%), proteins (35.1 to 45.4%) and carbohydrates (26.7 to 47.0%). Trifolium species were found to be rich in Se (contributing greater than 516% toward its RDA) with T. dubium having a concentration of 0.53 mg 10 g -1 , dry mass, which is higher than Brazil nuts. T. pratense was found to be the most suitable species for human consumption due to it having low levels of toxic metals (As, Cd and Pb) while being rich in macro- and micro-elements, especially Fe (7.84 mg 10 g -1 , dry mass) and Se (0.36 mg 10 g -1 , dry mass).
Comparison of breeding methods for forage yield in red clover
Directory of Open Access Journals (Sweden)
Libor Jalůvka
2009-01-01
Full Text Available Three methods of red clover (Trifolium pratense L. breeding for forage yield in two harvest years on locations in Bredelokke (Denmark, Hladké Životice (Czech Republic and Les Alleuds (France were compared. Three types of 46 candivars1, developed by A recurrent selection in subsequent generations (37 candivars, divided into early and late group, B polycross progenies (4 candivars and C geno-phenotypic selection (5 candivars were compared. The trials were sown in 2005 and cut three times in 2006 and 2007; their evaluation is based primarily on total yield of dry matter. The candivars developed by polycross and geno-phenotypic selections gave significantly higher yields than candivars from the recurrent selection. However, the candivars developed by the methods B and C did not differ significantly. The candivars developed by these progressive methods were suitable for higher yielding and drier environment in Hladké Životice (where was the highest yield level even if averaged annual precipitation were lower by 73 and 113 mm in comparison to other locations, respectively; here was average yield higher by 19 and 13% for B and C in comparison to A method. Highly significant interaction of the candivars with locations was found. It can be concluded that varieties specifically aimed to different locations by the methods B and C should be bred; also the parental entries should be selected there.
Investigation of exotic modes of spinning nuclei near 90 Zr
Indian Academy of Sciences (India)
2014-04-01
Apr 1, 2014 ... Recently, a digital data acquisition system with 96 channels has been set up for the Indian National Gamma Array (INGA) consisting of 24 Compton-suppressed clover detectors. The digital system provides higher throughput, better energy resolution and better stability for the multidetector ...
Directory of Open Access Journals (Sweden)
Piersiak Tomasz
2010-11-01
Full Text Available Abstract Background Rhizobium leguminosarum bv. trifolii is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants Trifolium spp. Bacterial surface polysaccharides are crucial for establishment of a successful symbiosis with legumes that form indeterminate-type nodules, such as Trifolium, Pisum, Vicia, and Medicago spp. and aid the bacterium in withstanding osmotic and other environmental stresses. Recently, the R. leguminosarum bv. trifolii RosR regulatory protein which controls exopolysaccharide production has been identified and characterized. Results In this work, we extend our earlier studies to the characterization of rosR mutants which exhibit pleiotropic phenotypes. The mutants produce three times less exopolysaccharide than the wild type, and the low-molecular-weight fraction in that polymer is greatly reduced. Mutation in rosR also results in quantitative alterations in the polysaccharide constituent of lipopolysaccharide. The rosR mutants are more sensitive to surface-active detergents, antibiotics of the beta-lactam group and some osmolytes, indicating changes in the bacterial membranes. In addition, the rosR mutants exhibit significant decrease in motility and form a biofilm on plastic surfaces, which differs significantly in depth, architecture, and bacterial viability from that of the wild type. The most striking effect of rosR mutation is the considerably decreased attachment and colonization of root hairs, indicating that the mutation affects the first stage of the invasion process. Infection threads initiate at a drastically reduced rate and frequently abort before they reach the base of root hairs. Although these mutants form nodules on clover, they are unable to fix nitrogen and are outcompeted by the wild type in mixed inoculations, demonstrating that functional rosR is important for competitive nodulation. Conclusions This report demonstrates the significant role RosR regulatory protein plays in
DEFF Research Database (Denmark)
D'Annibale, Alessandra; Sechi, Valentina; Larsen, Thomas
2017-01-01
plots with either perennial ryegrass (Lolium perenne L.), whiteclover (Trifolium repens L.) or a mixture of both in a Danish agricultural grassland 6 and 14 months after establishing the leys (September and May, respectively). Diet preferences were investigated via stable isotope analyses (SIA...... in the white clover than ryegrass plots. Changes in taxa specific density and traits distribution as a response to the C:N ratio of plant material, suggest that plant material quality was the main factor affecting the collembolan community,especially when comparing the two sampling occasions. Functional...... richness decreased under conditions of low quality material. In contrast to our hypothesis, population densities did not increase under mixture treatment and functional richness decreased. Our results suggest that habitat changes, via different plant composition, can affect some functional groups, having...
The data handling processor of the Belle II DEPFET detector
Energy Technology Data Exchange (ETDEWEB)
Germic, Leonard; Hemperek, Tomasz; Kishishita, Tetsuichi; Paschen, Botho; Luetticke, Florian; Krueger, Hans; Marinas, Carlos; Wermes, Norbert [Universitaet Bonn (Germany); Collaboration: Belle II-Collaboration
2016-07-01
A two layer highly granular DEPFET pixel detector will be operated as the innermost subsystem of the Belle II experiment, at the new Japanese super flavor factory (SuperKEKB). Such a finely segmented system will allow to improve the vertex reconstruction in such ultra high luminosity environment but, at the same time, the raw data stream generated by the 8 million pixel detector will exceed the capability of real-time processing due to its high frame rate, considering the limited material budged and strict space constrains. For this reason a new ASIC, the Data Handling Processor (DHP) is designed to provide data processing at the level of the front-end electronics, such as zero-suppression and common mode correction. Additional feature of the Data Handling Processor is the control block, providing control signals for the on-module ASICs used in the pixel detector. In this contribution, the description of the latest chip revision in TSMC 65 nm technology together with the latest test results of the interface functionality tests are presented.
The CMS HGCAL detector for HL-LHC upgrade
Martelli, Arabella
2017-01-01
The High Luminosity LHC (HL-LHC) will integrate 10 times more luminosity than the LHC, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry, and hallmarks the issue for future colliders. As part of its HL-LHC upgrade program, the CMS collaboration is designing a High Granularity Calorimeter to replace the existing endcap calorimeters. It features unprecedented transverse and longitudinal segmentation for both electromagnetic (ECAL) and hadronic (HCAL) compartments. This will facilitate particle-flow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The ECAL and a large fraction of HCAL will be based on hexagonal silicon sensors of 0.5 - 1 cm$^2$ cell size, with the remainder of the HCAL based on highly-segmented scintillators with SiPM readout. The intrinsic high-precision timing capabilities of the silicon sensors wi...
Energy Technology Data Exchange (ETDEWEB)
Contalbrigo, M., E-mail: contalbrigo@fe.infn.it
2015-07-01
A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to −25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.
Zhou, Yuan; Cheng, Xinyao; Xu, Xiangyang; Song, Enmin
2013-12-01
Segmentation of carotid artery intima-media in longitudinal ultrasound images for measuring its thickness to predict cardiovascular diseases can be simplified as detecting two nearly parallel boundaries within a certain distance range, when plaque with irregular shapes is not considered. In this paper, we improve the implementation of two dynamic programming (DP) based approaches to parallel boundary detection, dual dynamic programming (DDP) and piecewise linear dual dynamic programming (PL-DDP). Then, a novel DP based approach, dual line detection (DLD), which translates the original 2-D curve position to a 4-D parameter space representing two line segments in a local image segment, is proposed to solve the problem while maintaining efficiency and rotation invariance. To apply the DLD to ultrasound intima-media segmentation, it is imbedded in a framework that employs an edge map obtained from multiplication of the responses of two edge detectors with different scales and a coupled snake model that simultaneously deforms the two contours for maintaining parallelism. The experimental results on synthetic images and carotid arteries of clinical ultrasound images indicate improved performance of the proposed DLD compared to DDP and PL-DDP, with respect to accuracy and efficiency. Copyright © 2013 Elsevier B.V. All rights reserved.
GridPix detectors: Production and beam test results
International Nuclear Information System (INIS)
Koppert, W.J.C.; Bakel, N. van; Bilevych, Y.; Colas, P.; Desch, K.; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.P.; Kaminski, J.; Schmitz, J.; Schön, R.; Zappon, F.
2013-01-01
The innovative GridPix detector is a Time Projection Chamber (TPC) that is read out with a Timepix-1 pixel chip. By using wafer post-processing techniques an aluminium grid is placed on top of the chip. When operated, the electric field between the grid and the chip is sufficient to create electron induced avalanches which are detected by the pixels. The time-to-digital converter (TDC) records the drift time enabling the reconstruction of high precision 3D track segments. Recently GridPixes were produced on full wafer scale, to meet the demand for more reliable and cheaper devices in large quantities. In a recent beam test the contribution of both diffusion and time walk to the spatial and angular resolutions of a GridPix detector with a 1.2 mm drift gap are studied in detail. In addition long term tests show that in a significant fraction of the chips the protection layer successfully quenches discharges, preventing harm to the chip
GridPix detectors: Production and beam test results
Koppert, W. J. C.; van Bakel, N.; Bilevych, Y.; Colas, P.; Desch, K.; Fransen, M.; van der Graaf, H.; Hartjes, F.; Hessey, N. P.; Kaminski, J.; Schmitz, J.; Schön, R.; Zappon, F.
2013-12-01
The innovative GridPix detector is a Time Projection Chamber (TPC) that is read out with a Timepix-1 pixel chip. By using wafer post-processing techniques an aluminium grid is placed on top of the chip. When operated, the electric field between the grid and the chip is sufficient to create electron induced avalanches which are detected by the pixels. The time-to-digital converter (TDC) records the drift time enabling the reconstruction of high precision 3D track segments. Recently GridPixes were produced on full wafer scale, to meet the demand for more reliable and cheaper devices in large quantities. In a recent beam test the contribution of both diffusion and time walk to the spatial and angular resolutions of a GridPix detector with a 1.2 mm drift gap are studied in detail. In addition long term tests show that in a significant fraction of the chips the protection layer successfully quenches discharges, preventing harm to the chip.
3D track reconstruction capability of a silicon hybrid active pixel detector
Energy Technology Data Exchange (ETDEWEB)
Bergmann, Benedikt; Pichotka, Martin; Pospisil, Stanislav; Vycpalek, Jiri [Czech Technical University in Prague, Institute of Experimental and Applied Physics, Praha (Czech Republic); Burian, Petr; Broulim, Pavel [Czech Technical University in Prague, Institute of Experimental and Applied Physics, Praha (Czech Republic); University of West Bohemia, Faculty of Electrical Engineering, Pilsen (Czech Republic); Jakubek, Jan [Advacam s.r.o., Praha (Czech Republic)
2017-06-15
Timepix3 detectors are the latest generation of hybrid active pixel detectors of the Medipix/Timepix family. Such detectors consist of an active sensor layer which is connected to the readout ASIC (application specific integrated circuit), segmenting the detector into a square matrix of 256 x 256 pixels (pixel pitch 55 μm). Particles interacting in the active sensor material create charge carriers, which drift towards the pixelated electrode, where they are collected. In each pixel, the time of the interaction (time resolution 1.56 ns) and the amount of created charge carriers are measured. Such a device was employed in an experiment in a 120 GeV/c pion beam. It is demonstrated, how the drift time information can be used for ''4D'' particle tracking, with the three spatial dimensions and the energy losses along the particle trajectory (dE/dx). Since the coordinates in the detector plane are given by the pixelation (x,y), the x- and y-resolution is determined by the pixel pitch (55 μm). A z-resolution of 50.4 μm could be achieved (for a 500 μm thick silicon sensor at 130 V bias), whereby the drift time model independent z-resolution was found to be 28.5 μm. (orig.)
3D track reconstruction capability of a silicon hybrid active pixel detector
Bergmann, Benedikt; Pichotka, Martin; Pospisil, Stanislav; Vycpalek, Jiri; Burian, Petr; Broulim, Pavel; Jakubek, Jan
2017-06-01
Timepix3 detectors are the latest generation of hybrid active pixel detectors of the Medipix/Timepix family. Such detectors consist of an active sensor layer which is connected to the readout ASIC (application specific integrated circuit), segmenting the detector into a square matrix of 256 × 256 pixels (pixel pitch 55 μm). Particles interacting in the active sensor material create charge carriers, which drift towards the pixelated electrode, where they are collected. In each pixel, the time of the interaction (time resolution 1.56 ns) and the amount of created charge carriers are measured. Such a device was employed in an experiment in a 120 GeV/c pion beam. It is demonstrated, how the drift time information can be used for "4D" particle tracking, with the three spatial dimensions and the energy losses along the particle trajectory (dE/dx). Since the coordinates in the detector plane are given by the pixelation ( x, y), the x- and y-resolution is determined by the pixel pitch (55 μm). A z-resolution of 50.4 μm could be achieved (for a 500 μm thick silicon sensor at 130 V bias), whereby the drift time model independent z-resolution was found to be 28.5 μm.
The ultra low mass cooling system of the Belle II DEPFET detector
International Nuclear Information System (INIS)
Ruiz-Valls, P.; Marinas, C.
2013-01-01
The new Japanese Super Flavor Factory Belle II is designed with high precision in mind, making a good vertex resolution a necessity. In order to achieve the required resolution in the vertex reconstruction, besides highly segmented pixel detectors, the material budget has to be kept at very low levels, since more material results in multiple scattering and degrades the resolution. As a consequence, there is a direct impact on the cooling system, that has to be carefully designed, not allowing active cooling pipes inside the acceptance region. In this asymmetric e + e − experiment the angular acceptance ranges from 17° to 150°, leaving room for support structures outside this range. The Belle II vertex detector includes DEPFET technology in its vertex detector the front end electronics (FEE) of which, placed outside the acceptance, can be cooled by 2-phase CO 2 through massive support structures while the sensitive area relies on forced convection with cold nitrogen gas
Pramana – Journal of Physics | Indian Academy of Sciences
Indian Academy of Sciences (India)
2014-11-01
Nov 1, 2014 ... An experimental campaign aimed at studying various high spin phenomena using the Indian National Gamma Array (INGA) at the BARC–TIFR Pelletron Linac Facility has been successfully completed. The array consisting of a large number of Compton-suppressed clover detectors was coupled to a digital ...
Brookhaven segment interconnect
International Nuclear Information System (INIS)
Morse, W.M.; Benenson, G.; Leipuner, L.B.
1983-01-01
We have performed a high energy physics experiment using a multisegment Brookhaven FASTBUS system. The system was composed of three crate segments and two cable segments. We discuss the segment interconnect module which permits communication between the various segments
The ITk strips tracker for the phase-II upgrade of the ATLAS detector of the HL-LHC
Koutoulaki, Afroditi; The ATLAS collaboration
2016-01-01
The inner detector of the present ATLAS detector has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the next-generation tracking detector proposed for the High Luminosity LHC (HL-LHC), the so-called ATLAS Phase-II Upgrade, the particle densities and radiation levels will be higher by as much as a factor of ten. The new detectors must be faster, they need to be more highly segmented, and covering more area. They also need to be more resistant to radiation, and they require much greater power delivery to the front-end systems. At the same time, they cannot introduce excess material which could undermine performance. For those reasons, the inner tracker of the ATLAS detector must be redesigned and rebuilt completely. The design of the ATLAS Upgrade inner tracker (ITk) has already been defined. It consists of several layers of silicon particle detectors. The innermost layers will be composed of silicon pixel sensors, and the outer layers will consist of s...
Turner, K E; Cassida, K A; Zerby, H N
2014-12-01
This experiment was conducted in 2005-2007 to evaluate carcass and chevon (goat meat) quality parameters when meat-goat kids (n=72) were finished on alfalfa (Medicago sativa L; ALF); red clover (Trifolium pratense L.; RCG); or orchardgrass (Dactylis glomerata L.; OGR) pastures. Carcass conformation score was greater (P=0.08) when meat-goat kids were finished on ALF compared to OGR with RCG intermediate. Chevon meat samples from goats finished on the three pasture treatments did not differ in ash, intramuscular fat, or crude protein content or in concentrations of omega6 and omega3 fatty acids, or the omega6 to omega3 ratio. Goats finished on OGR had higher (Pmeat-goat kids finished on ALF, RCG, or ORG produced desirable carcass weights for most niche markets in the USA. Chevon is a low-fat meat option with high desirable fatty acids for human diets. Published by Elsevier Ltd.
International Nuclear Information System (INIS)
Mir-Akbari, H.; Ripsweden, J.; Jensen, J.; Pichler, P.; Sylven, C.; Cederlund, K.; Rueck, A.
2009-01-01
Background: Recently, 64-detector-row computed tomography coronary angiography (CTA) has been introduced for the noninvasive diagnosis of coronary artery disease. Purpose: To evaluate the diagnostic capacity and limitations of a newly established CTA service. Material and Methods: In 101 outpatients with suspected coronary artery disease, 64-detector-row CTA (VCT Lightspeed 64; GE Healthcare, Milwaukee, WI., USA) was performed before invasive coronary angiography (ICA). The presence of >50% diameter coronary stenosis on CTA was rated by two radiologists recently trained in CTA, and separately by an experienced colleague. Diagnostic performance of CTA was calculated on segment, vessel, and patient levels, using ICA as a reference. Segments with a proximal reference diameter <2 mm or with stents were not analyzed. Results: In 51 of 101 patients and 121 of 1280 segments, ICA detected coronary stenosis. In 274 of 1280 (21%) segments, CTA had non-diagnostic image quality, the main reasons being severe calcifications (49%), motion artifacts associated with high or irregular heart rate (45%), and low contrast opacification (14%). Significantly more women (43%) had non-diagnostic scans compared to men (20%). A heart rate above 60 beats per minute was associated with significantly more non-diagnostic patients (38% vs. 18%). In the 1006 diagnostic segments, CTA had a sensitivity of 78%, specificity of 95%, positive predictive value (PPV) of 54%, and negative predictive value (NPV) of 98% for detecting significant coronary stenosis. In 29 patients, CTA was non-diagnostic. In the remaining 72 patients, sensitivity was 100%, specificity 65%, PPV 79%, and NPV 100%. The use of a more experienced CTA reader did not improve diagnostic performance. Conclusion: CTA had a very high negative predictive value, but the number of non-diagnostic scans was high, especially in women. The main limitations were motion artifacts and vessel calcifications, while short experience in CTA did not
Tillard, Guyléne; van Ham, Robert; Ballard, Ross; Farquharson, Elizabeth; Gerard, Emily; Geurts, Rene; Brown, Matthew; Ridgway, Hayley; O’Callaghan, Maureen
2018-01-01
Biological nitrogen fixation through the legume-rhizobia symbiosis is important for sustainable pastoral production. In New Zealand, the most widespread and valuable symbiosis occurs between white clover (Trifolium repens L.) and Rhizobium leguminosarum bv. trifolii (Rlt). As variation in the population size (determined by most probable number assays; MPN) and effectiveness of N-fixation (symbiotic potential; SP) of Rlt in soils may affect white clover performance, the extent in variation in these properties was examined at three different spatial scales: (1) From 26 sites across New Zealand, (2) at farm-wide scale, and (3) within single fields. Overall, Rlt populations ranged from 95 to >1 x 108 per g soil, with variation similar at the three spatial scales assessed. For almost all samples, there was no relationship between rhizobia population size and ability of the population to fix N during legume symbiosis (SP). When compared with the commercial inoculant strain, the SP of soils ranged between 14 to 143% efficacy. The N-fixing ability of rhizobia populations varied more between samples collected from within a single hill country field (0.8 ha) than between 26 samples collected from diverse locations across New Zealand. Correlations between SP and calcium and aluminium content were found in all sites, except within a dairy farm field. Given the general lack of association between SP and MPN, and high spatial variability of SP at single field scale, provision of advice for treating legume seed with rhizobia based on field-average MPN counts needs to be carefully considered. PMID:29489845
Mishra, Ajay; Aloimonos, Yiannis
2009-01-01
The human visual system observes and understands a scene/image by making a series of fixations. Every fixation point lies inside a particular region of arbitrary shape and size in the scene which can either be an object or just a part of it. We define as a basic segmentation problem the task of segmenting that region containing the fixation point. Segmenting the region containing the fixation is equivalent to finding the enclosing contour- a connected set of boundary edge fragments in the edge map of the scene - around the fixation. This enclosing contour should be a depth boundary.We present here a novel algorithm that finds this bounding contour and achieves the segmentation of one object, given the fixation. The proposed segmentation framework combines monocular cues (color/intensity/texture) with stereo and/or motion, in a cue independent manner. The semantic robots of the immediate future will be able to use this algorithm to automatically find objects in any environment. The capability of automatically segmenting objects in their visual field can bring the visual processing to the next level. Our approach is different from current approaches. While existing work attempts to segment the whole scene at once into many areas, we segment only one image region, specifically the one containing the fixation point. Experiments with real imagery collected by our active robot and from the known databases 1 demonstrate the promise of the approach.
ECFA Detector R&D Panel, Review Report
Abramowicz, H.; Afanaciev, K.; Aguilar, J.; Alvarez, E.; Bambade, P.; Bortko, L.; Bozovic-Jelisavcic, I.; Castro, E.; Chelkov, G.; Coca, C.; Daniluk, W.; Dragone, A.; Dumitru, L.; Elsener, K.; Emeliantchik, I.; Firu, E.; Fischer, J.; Fiutowski, T.; Ghenescu, V.; Gostkin, M.; Grzelak, G.; Haller, G.; Henschel, H.; Ignatenko, A.; Idzik, M.; Ito, K.; Kananov, S.; Kielar, E.; Kollowa, S.; Kotula, J.; Krumstein, Z.; Krupa, B.; Kulis, S.; Lange, W.; Levy, A.; Levy, I.; Linssen, L.; Lohmann, W.; Lukic, S.; Moron, J.; Moszczynski, A.; Nauenberg, U.; Neagu, A.; Novgorodova, O.; Nuiry, F.X.; Ohlerich, M.; Orlandea, M.; Oleinik, G.; Oliwa, K.; Olshevski, A.; Pandurovic, M.; Pawlik, B.; Preda, T.; Przyborowski, D.; Sato, Y.; Sadeh, I.; Sailer, A.; Schumm, B.; Schuwalow, S.; Schwartz, R.; Smiljanic, I.; Swientek, K.; Takubo, Y.; Teodorescu, E.; Wierba, W.; Yamamoto, H.; Zawiejski, L.; Zgura, T.S.; Zhang, J.
2014-01-01
Two special calorimeters are foreseen for the instrumentation of the very forward region of an ILC or CLIC detector; a luminometer (LumiCal) designed to measure the rate of low angle Bhabha scattering events with a precision better than 10−3 at the ILC and 10−2 at CLIC, and a low polar-angle calorimeter (BeamCal). The latter will be hit by a large amount of beamstrahlung remnants. The intensity and the spatial shape of these depositions will provide a fast luminosity estimate, as well as determination of beam parameters. The sensors of this calorimeter must be radiation-hard. Both devices will improve the e.m. hermeticity of the detector in the search for new particles. Finely segmented and very compact electromagnetic calorimeters will match these requirements. Due to the high occupancy, fast front-end electronics will be needed. Monte Carlo studies were performed to investigate the impact of beam-beam interactions and physics background processes on the luminosity measurement, and of beamstrahlung on th...
GeoSegmenter: A statistically learned Chinese word segmenter for the geoscience domain
Huang, Lan; Du, Youfu; Chen, Gongyang
2015-03-01
Unlike English, the Chinese language has no space between words. Segmenting texts into words, known as the Chinese word segmentation (CWS) problem, thus becomes a fundamental issue for processing Chinese documents and the first step in many text mining applications, including information retrieval, machine translation and knowledge acquisition. However, for the geoscience subject domain, the CWS problem remains unsolved. Although a generic segmenter can be applied to process geoscience documents, they lack the domain specific knowledge and consequently their segmentation accuracy drops dramatically. This motivated us to develop a segmenter specifically for the geoscience subject domain: the GeoSegmenter. We first proposed a generic two-step framework for domain specific CWS. Following this framework, we built GeoSegmenter using conditional random fields, a principled statistical framework for sequence learning. Specifically, GeoSegmenter first identifies general terms by using a generic baseline segmenter. Then it recognises geoscience terms by learning and applying a model that can transform the initial segmentation into the goal segmentation. Empirical experimental results on geoscience documents and benchmark datasets showed that GeoSegmenter could effectively recognise both geoscience terms and general terms.