1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference最新文献

{"title":"Evaluation Of Wavelength Shifters For Spectral Separation Of Barium Fluoride Emissions","authors":"T. Devol, D. Wehe, O.F. Knoll","doi":"10.1109/NSSMIC.1993.701734","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701734","url":null,"abstract":"Application of the barium fluoride (BaF2) scintillator for characterization of intense radiation fields has been pursued since the fast component was discovered in the early 1980's. Unfortunately, ∼ 80% of the scintillator emissions have a slow ∼ 600 ns decay time constant. The long decay time hampers the use of BaF2 at high count rates because the slow emissions appear as an afterglow which has an intensity that varies with the interaction rate in the crystal. The temporal separation of BaF2 emissions by spectral separation using wavelength shifting techniques has been explored in this work. Of the wavelength shifting techniques that were examined, the solvent excitation technique showed the greatest potential, but was insufficient by itself to suppress the slow emissions to the desired degree. All the wavelength shifting techniques yield an enhanced ratio of fast to slow photons, but a decreased fast photoelectron yield.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115931090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-speed Reconstruction Of SPECT Mages With A Tailored Piecewise Neural Network","authors":"J. Kerr, E. Bartlett","doi":"10.1109/NSSMIC.1993.701853","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701853","url":null,"abstract":"Artificial neural networks (ANNs) have proven to be highly adept at mapping complex functional relationships. We have previously shown that a standard backpropagation neural network can be trained to reconstruct sections of single photon emission computed tomography (SPECT) images based on the planar image projections as inputs. In this study, we demonstrate that a neural network that utilizes a tailored three-phase piecewise activation function is able to perform high-speed reconstructions of SPECT images after learning the relationship between the planar images and the tomographic reconstructions. In addition, the tailored piecewise neural network produces reconstructions with significantly lower RMS error, and does so in far less training iterations, than a standard backpropagation ANN. The tailored piecewise function used in this research enables the network to train on a continuous range of outputs more efficiently than with a standard sigmoidal function. Based on the results obtained, we hypothesize that the optimal ANN transfer function or functions, are directly related to the statistical distribution of the training set data. As a preliminary demonstration, a neural network with statistically derived activation functions is shown to have better training and generalization characteristics for SPECT reconstruction than either the single sigmoidal or the three- phase sigmoidalmore » activation functions.« less","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132322947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 12-channel VMEBUS-based Pulse-height Analysis Module","authors":"G. J. Arnone","doi":"10.1109/NSSMIC.1993.701710","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701710","url":null,"abstract":"The author describes a 12-channel VMEbus-based pulse-height analysis board that was designed for use in a high-rate, multidetector, gamma-ray imaging system. This module was designed to minimize dead-time losses and to allow all key parameters to be software controlled. Gamma-ray detectors are connected directly to this module, eliminating the need for additional electronics.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124367856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design Of A Trigger And Data Acquisition System For A Detector At Pep-II","authors":"R. Becker-Szendy, D. Briggs, G. Haller, J. Hoeflich, W. Innes","doi":"10.1109/NSSMIC.1993.701766","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701766","url":null,"abstract":"This paper proposes a design of a trigger and data acquisition system for a detector at the PEP-II B Factory. The system is asynchronous, data-driven, and scalable. Design goals include orthogonal tracking and calorimetric triggers, minimal dead time, graceful degradation, high efficiency, and useful performance in the face of backgrounds so high as to overwhelm reconstruction. Also described are instrumentation of the Drift Chamber, based on 8-bit FADCs, and of the Calorimeter, based on a new custom integrated circuit, the Charge Amplifier with Range Encoding (CARE), and 10-bit ADCs. This design employs commercial embedded CPUs in VME and VXI crates. >","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130507253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection geometry and reconstruction error in magnetic source imaging","authors":"P. Hughett, T. Budinger","doi":"10.1109/NSSMIC.1993.373539","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.373539","url":null,"abstract":"A recently developed reconstruction algorithm for magnetic source imaging exploits prior knowledge about source location, source power density, detector geometry, and detector noise power to obtain an explicit estimate of the reconstruction error. The authors demonstrate the application of the new algorithm to the optimal design of practical detector arrays to minimize the reconstruction error in specific applications. For a representative configuration for magnetocardiography, the optimal array width (for minimum reconstruction error) varies from 19 to 28 cm depending on the assumed source depth, number of detectors, source power, and noise power. The reconstruction accuracy ranges from 5% of the a priori standard deviation for the sources nearest the detector plane to 95% of the a priori deviation for the deepest sources. The reconstruction error was found to depend on accidental alignments between dipole sources and point detectors, indicating that a more sophisticated model is required for accurate estimates of reconstruction error. The error calculation is fast, taking about a second for this problem on a workstation-class computer. The availability of a method for rapidly computing the reconstruction error for any given source characteristics and detector geometry will facilitate the optimal design of magnetometer array size, element spacing, and orientation for specific applications in biomagnetic and geomagnetic source imaging.<<ETX>>","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127900715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Bipolar Analog Front-end Integrated Circuit For The SDC Silicon Tracker","authors":"I. Kipnis, H. Spieler, T. Collins","doi":"10.1109/NSSMIC.1993.701772","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701772","url":null,"abstract":"A low-noise, low-power, high-bandwidth, radiation hard, silicon bipolar-transistor full-custom integrated circuit (IC) containing 64 channels of analog signal processing has been developed for the SDC silicon tracker. The IC was designed and tested at LBL and was fabricated using AT&T`s CBIC-U2, 4 GHz f{sub T} complementary bipolar technology. Each channel contains the following functions: low-noise preamplification, pulse shaping and threshold discrimination. This is the first iteration of the production analog IC for the SDC silicon tracker. The IC is laid out to directly match the 50 {mu}m pitch double-sided silicon strip detector. The chip measures 6.8 mm {times} 3.1 mm and contains 3,600 transistors. Three stages of amplification provide 180 mV/fC of gain with a 35 nsec peaking time at the comparator input. For a 14 pF detector capacitance, the equivalent noise charge is 1300 el. rms at a power consumption of 1 mW/channel from a single 3.5 V supply. With the discriminator threshold set to 4 times the noise level, a 16 nsec time-walk for 1.25 to 10fC signals is achieved using a time-walk compensation network. Irradiation tests at TRIUMF to a {Phi}=10{sup 14} protons/cm{sup 2} have been performed on the IC, demonstrating the radiation hardness of the complementarymore » bipolar process.« less","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"256 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122859785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design And Engineering Aspects Of Avalanche Photodiode PET Tomograph","authors":"R. Lecomte, J. Cadorette, P. Richard, S. Rodrigue, D. Rouleau","doi":"10.1109/NSSMIC.1993.701813","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701813","url":null,"abstract":"Design and Engineering Aspects of Avalanche Photodiode","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115398133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Applying THERMAC To Recover Lost Megawatts At Power Plants","authors":"K. J. Doran, P. Jain","doi":"10.1109/NSSMIC.1993.701809","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701809","url":null,"abstract":"THERMAC is an integrated software tool for monitoring and evaluating the thermal performance of power plants, combining smg analytical capabilities with a graphical user interface and database. The software has been installed, in either on-line or off-line mode, at more than 30 nuclear and fossil-fired plants by 19 utility and non-utility customers in the USA, Canada and Japan. THERMAC analyzes plant measurements to evaluate thermal performance at both the component and system levels. THERMAC employs actual plant data and statistically accounts for missing or inconsistent data. The software does not require any additional plant instrumentation to perfonn analyses. THERMAC can archive historical data as well as generate trend plots and performance reports. The graphical user interface is employed to build plant specific models. “What-if‘ studies can be conducted to predict the impact of corrective action on thermal performance, prioritize plant maintenance actions, and study alternate system designs. . One way in which THERMAC can be employed to reduce operating and maintenance (OM yet, these can be identified and quantified using THERMAC. This paper describes THERMAC, its methodology, -and some experiences that utilities have had in using the software to monitor and analyze plant performance, identify equipment problems, and assess the impact on lost generation. I. hITRODU(JTI0N New federal regulations and the power industry’s responses to those regulatory changes will alter the utility environment in the coming decade. The most pervasive changes will come from the Energy Policy Act of 1992. This act affects utilities in many ways, but the most important changes concern power generation sources. Utilities must now purchase power from all fms that offer to sell it, and the utilities must sell the cheapest power to their customers first. Hence, any independent power producer (IPP) that can generate and sell power at a rate lower than the utility’s must be afforded access to the utility’s transmission lines; moreover, the IPP’s power must be sold before that generated by the utility. The utilities will thus be harder pressed to sell their own electric generation.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116940734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation And Application Of Reprojection Methods For 3D PET","authors":"T. M. Guerrero, Y. Tai, A. Chatziioannou, D. Yu, S. Huang, M. Dahlbom, E. Hoffman","doi":"10.1109/NSSMIC.1993.701818","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701818","url":null,"abstract":"This paper reviews the various methods of sinogram calculation or reprojection and those appropriate for 3D PET. Then a rapid calculation method that utilizes the 8fold 2D symmetry of the PET data for single sinogram calculations is introduced to 3D. Two ray-tracing methods that differ in their model of the voxel are implemented and their speed-up measured using the rapid calculation method. The first voxel model assumes parallelepiped shaped discrete voxels and the second model approximates the data as a sampled continuous distribution. The two ray-tracing methods of reprojection are compared on phantom data for their resolution loss and sampling error. Each method is applied to the problem of attenuation correction factor calculation, both 3D from regions of interest geometry data and 3D from 2D, then compared with measured attenuation correction data. Due to its simplicity and speed the parallelepiped voxel method is recommended for use in 3D PET algorithms and the associated error is characterized.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121371727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beam Test Of The SDC Double-sided Silicon Strip Detector","authors":"Y. Unno, F. Hinode, T. Akagi, T. Kohriki, N. Ujiie, Y. Iwata, T. Ohmoto, T. Ohsugi, T. Ohyama, T. Hatakenaka, N. Tamura, S. Kobayashi, A. Murakami, M. Tezuka, R. Takashima, T. Aso, H. Miyata, M. Daigo, M. Higuchi, I. Kipnis, H. Spieler, J. DeWitt, D. Dorfan, A. Grillo, B. Hubbard, J. Rahn, W. Rowe, H. Sadrozinski, A. Seiden, E. Spencer, A. Webster, M. Wilder, M. Frautschi, J. Matthews","doi":"10.1109/NSSMIC.1993.701869","DOIUrl":"https://doi.org/10.1109/NSSMIC.1993.701869","url":null,"abstract":"A beam test was executed to evaluate the behavior of the first prototype radiation-hard double-sided silicon microstrip sensor for the SDC silicon tracking system. Pions of 4 GeV/c in a test bcamline at KEK illuminated three planes of detectors. Thc signals wcrc amplified, shaped, and discriminated with TEKZ bipolar analog LSI's, and the on-off levels were sampled at l0MHz clock with CMOS digiwl LSI's, asynchronously with beam triggers. The detectors were rotated in null and 1 .O Tesla magnetic fields. The efficiencies were found to be 98-9996. The position resolutions were 12.5pm. where the multi-strip hit fraction was 30-40%. There was no essential difference in the performance of the pand the n-sides. The multi-strip hit fraction showed a clear rotation and magnetic-field dependence. From the angles where the fractions were minimum in the 1T magnetic field, the Hall mobilities of the electrons and holes were obtained to be 1391k43 (clcctrons) and 325f30 (holes) cm2/Vs.","PeriodicalId":287813,"journal":{"name":"1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125862602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}