Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1008647
M. Khodaverdi, F. Pauly, S. Weber, G. Schroder, K. Ziemons, R. Sievering, H. Halling
We are developing an X-ray computed tomography (CT) system which will be combined with a high resolution animal PET system. This permits acquisition of both molecular and anatomical images in a single machine. In particular the CT will also be utilized for the quantification of the animal PET data by providing accurate data for attenuation correction. A first prototype has been built using a commercially available plane silicon diode detector. A cone-beam reconstruction provides the images using the Feldkamp algorithm. First measurements with this system have been performed on a mouse. It could be shown that the CT setup fulfils all demands for a high quality image of the skeleton of the mouse. It is also suited for soft tissue measurements. To improve contrast and resolution and to acquire the X-ray energy further development of the system, especially the use of semiconductor detectors and iterative reconstruction algorithms are planned.
{"title":"Preliminary studies of a micro-CT for a combined small animal PET/CT scanner","authors":"M. Khodaverdi, F. Pauly, S. Weber, G. Schroder, K. Ziemons, R. Sievering, H. Halling","doi":"10.1109/NSSMIC.2001.1008647","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008647","url":null,"abstract":"We are developing an X-ray computed tomography (CT) system which will be combined with a high resolution animal PET system. This permits acquisition of both molecular and anatomical images in a single machine. In particular the CT will also be utilized for the quantification of the animal PET data by providing accurate data for attenuation correction. A first prototype has been built using a commercially available plane silicon diode detector. A cone-beam reconstruction provides the images using the Feldkamp algorithm. First measurements with this system have been performed on a mouse. It could be shown that the CT setup fulfils all demands for a high quality image of the skeleton of the mouse. It is also suited for soft tissue measurements. To improve contrast and resolution and to acquire the X-ray energy further development of the system, especially the use of semiconductor detectors and iterative reconstruction algorithms are planned.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125386205","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1008591
Ji Chen, J. Galt, J. Valentine, T. Faber, E.V. Garcia
The accuracy of SPECT images is compromised and artifacts may be produced when the radiopharmaceutical distribution changes during image acquisition. Optimization of SPECT acquisition protocols for changing tracer distributions can be difficult not only in patient studies (undesirability of performing repeat studies on the same patient) but also in phantom studies (difficulty of emulating the changing distributions). This study proposes a simulation that allows computer modeling of both tracer kinetics and different acquisition schemes. /sup 99m/Tc Teboroxime (Bracco Diagnostics) is used as a model. SPECT acquisition of a software phantom (NCAT, UNC Chapel Hill) is simulated with photon attenuation, collimator resolution, Compton scatter, Poisson noise, and changing tracer distribution. Short-axis uniformity is used to assess the severity of artifacts in the myocardium. The simulation produces similar artifacts to those found in patient studies with /sup 99m/Tc Teboroxime. This simulation methodology can provide a valuable tool for testing novel acquisition and processing techniques and to facilitate the optimization of SPECT images of changing tracer distributions. Summed fanning (back and forth) acquisitions have been tested and artifact reduced short-axis images obtained. Image restoration techniques are proposed to further improve the image quality. Furthermore, the simulated studies can be compared to the simulations with assigned low liver uptake and no tracer clearance from the myocardium to detect and resolve artifacts through variations in the acquisition and processing schemes.
{"title":"Modeling SPECT acquisition and processing of changing radiopharmaceutical distributions","authors":"Ji Chen, J. Galt, J. Valentine, T. Faber, E.V. Garcia","doi":"10.1109/NSSMIC.2001.1008591","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008591","url":null,"abstract":"The accuracy of SPECT images is compromised and artifacts may be produced when the radiopharmaceutical distribution changes during image acquisition. Optimization of SPECT acquisition protocols for changing tracer distributions can be difficult not only in patient studies (undesirability of performing repeat studies on the same patient) but also in phantom studies (difficulty of emulating the changing distributions). This study proposes a simulation that allows computer modeling of both tracer kinetics and different acquisition schemes. /sup 99m/Tc Teboroxime (Bracco Diagnostics) is used as a model. SPECT acquisition of a software phantom (NCAT, UNC Chapel Hill) is simulated with photon attenuation, collimator resolution, Compton scatter, Poisson noise, and changing tracer distribution. Short-axis uniformity is used to assess the severity of artifacts in the myocardium. The simulation produces similar artifacts to those found in patient studies with /sup 99m/Tc Teboroxime. This simulation methodology can provide a valuable tool for testing novel acquisition and processing techniques and to facilitate the optimization of SPECT images of changing tracer distributions. Summed fanning (back and forth) acquisitions have been tested and artifact reduced short-axis images obtained. Image restoration techniques are proposed to further improve the image quality. Furthermore, the simulated studies can be compared to the simulations with assigned low liver uptake and no tracer clearance from the myocardium to detect and resolve artifacts through variations in the acquisition and processing schemes.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126650155","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1009207
D. Strul, J. Sutcliffe-Goulden, P. Halstead, P. Marsden
Optimising the collection of scintillation light is essential for good PET scanner performance, and even more so when the crystals are read out through optical fibres. Acid etching had been proposed as a cost-effective alternative to mechanical polishing, but there are discrepancies between the results published so far. The aim of this work is to gain a better understanding of acid etching and of its effects on the light yield and to assess its application to fibre-optic based configurations, We have examined the surface state of LSO crystals etched for various times and measured their light output in different configurations, with both direct and fibre-optic readout. Our results indicate that crystal etching is a complex process, where different crystal faces may be etched in different ways. Acid etching always resulted in an improvement the light yield and energy resolution of the crystals, and was as efficient as or in many cases superior to, mechanical polishing. While this improvement was somewhat limited for the configurations with direct readout of the crystals we tested, it was much larger for the fibre-optic based configuration.
{"title":"Optimisation of fibre-optic readout of LSO scintillation crystals with acid etching","authors":"D. Strul, J. Sutcliffe-Goulden, P. Halstead, P. Marsden","doi":"10.1109/NSSMIC.2001.1009207","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1009207","url":null,"abstract":"Optimising the collection of scintillation light is essential for good PET scanner performance, and even more so when the crystals are read out through optical fibres. Acid etching had been proposed as a cost-effective alternative to mechanical polishing, but there are discrepancies between the results published so far. The aim of this work is to gain a better understanding of acid etching and of its effects on the light yield and to assess its application to fibre-optic based configurations, We have examined the surface state of LSO crystals etched for various times and measured their light output in different configurations, with both direct and fibre-optic readout. Our results indicate that crystal etching is a complex process, where different crystal faces may be etched in different ways. Acid etching always resulted in an improvement the light yield and energy resolution of the crystals, and was as efficient as or in many cases superior to, mechanical polishing. While this improvement was somewhat limited for the configurations with direct readout of the crystals we tested, it was much larger for the fibre-optic based configuration.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122572134","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1008603
I. Buvat, C. Riddell
We describe a non-parametric bootstrap method to estimate the statistical properties of single photon emission computed tomography (SPECT) and positron emission tomography (PET) images, whatever the type of noise in the projections and the reconstruction algorithm. Using analytical simulations and real PET data, this method is shown to accurately predict the statistical distribution, hence the variance, of reconstructed pixel values for both linear and nonlinear reconstruction algorithms.
{"title":"A bootstrap approach for analyzing the statistical properties of SPECT and PET images","authors":"I. Buvat, C. Riddell","doi":"10.1109/NSSMIC.2001.1008603","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008603","url":null,"abstract":"We describe a non-parametric bootstrap method to estimate the statistical properties of single photon emission computed tomography (SPECT) and positron emission tomography (PET) images, whatever the type of noise in the projections and the reconstruction algorithm. Using analytical simulations and real PET data, this method is shown to accurately predict the statistical distribution, hence the variance, of reconstructed pixel values for both linear and nonlinear reconstruction algorithms.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121018768","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1008560
R. Freifelder, C. Cardi, I. Grigoraş, J. Saffer, J. Karp
We present the first imaging results from phantom measurements of a dedicated, breast-only positron emission imager, BPET, using NaI(Tl) Curve Plate detectors. The scanner uses 19 mm thick NaI(Tl) detectors in a split-ring design which surrounds the breast as the woman lies prone and the breast hangs down from the body. Because the detectors are close to the breast and the scanner detects photons that do not pass through the body, system sensitivity and spatial resolution are both optimized. The split ring design provides for flexibility for needle aspirations of masses or alternate viewing orientations. We have measured energy resolution, spatial resolution, scatter fraction, and system sensitivity. We have compared the BPET scanner's performance to our clinical whole-body scanner using a breast phantom with hot spheres simulating lesions. The results show that for activity concentrations that correspond to clinical FDG doses, the dedicated scanner has better lesion detectability than the whole-body scanner for the 20 cm detector separation used.
{"title":"First results of a dedicated breast PET imager, BPET, using NaI(Tl) curve plate detectors","authors":"R. Freifelder, C. Cardi, I. Grigoraş, J. Saffer, J. Karp","doi":"10.1109/NSSMIC.2001.1008560","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008560","url":null,"abstract":"We present the first imaging results from phantom measurements of a dedicated, breast-only positron emission imager, BPET, using NaI(Tl) Curve Plate detectors. The scanner uses 19 mm thick NaI(Tl) detectors in a split-ring design which surrounds the breast as the woman lies prone and the breast hangs down from the body. Because the detectors are close to the breast and the scanner detects photons that do not pass through the body, system sensitivity and spatial resolution are both optimized. The split ring design provides for flexibility for needle aspirations of masses or alternate viewing orientations. We have measured energy resolution, spatial resolution, scatter fraction, and system sensitivity. We have compared the BPET scanner's performance to our clinical whole-body scanner using a breast phantom with hot spheres simulating lesions. The results show that for activity concentrations that correspond to clinical FDG doses, the dedicated scanner has better lesion detectability than the whole-body scanner for the 20 cm detector separation used.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121058161","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1008477
W. Hollerman, E. Gates, P. Boudreaux, G. Glass
Until recently, it was difficult to measure properties of individual fluor grains. The development of an accelerator-based nuclear microprobe, currently available at the Louisiana Accelerator Center (LAC), has made this type of research possible. Using ion beams as small as 1 /spl times/ 1 /spl mu/m (horizontal /spl times/ vertical extent), it is now possible to measure properties of individual fluor grains. Starting in 2000, a research program was initiated to determine the microscopic fluorescence properties for selected rare earth compounds, like Y/sub 2/O/sub 2/S:Eu. Particle induced X-ray emission (PIXE) was used to characterize individual fluor grains. Individual Y/sub 2/O/sub 2/S:Eu grains are clearly visible in the analysis and are less than 10 /spl mu/m in extent.
{"title":"Results from a nuclear microprobe analysis of selected rare earth fluor materials","authors":"W. Hollerman, E. Gates, P. Boudreaux, G. Glass","doi":"10.1109/NSSMIC.2001.1008477","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008477","url":null,"abstract":"Until recently, it was difficult to measure properties of individual fluor grains. The development of an accelerator-based nuclear microprobe, currently available at the Louisiana Accelerator Center (LAC), has made this type of research possible. Using ion beams as small as 1 /spl times/ 1 /spl mu/m (horizontal /spl times/ vertical extent), it is now possible to measure properties of individual fluor grains. Starting in 2000, a research program was initiated to determine the microscopic fluorescence properties for selected rare earth compounds, like Y/sub 2/O/sub 2/S:Eu. Particle induced X-ray emission (PIXE) was used to characterize individual fluor grains. Individual Y/sub 2/O/sub 2/S:Eu grains are clearly visible in the analysis and are less than 10 /spl mu/m in extent.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116536774","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1009246
N. Motomura, K. Nambu, A. Kojima, S. Tomiguchi, K. Ogawa
Due to the collimator aperture, the spatial resolution of SPECT data varies with source-to-detector distance. Since radius of detector rotation is bigger when scanning larger patients, the spatial resolution is degraded in these cases. Emitted gamma rays travel not only along the central axis of the collimator hole but also off-axis due to collimator aperture. However, an off-axis ray at one angle would be a central-axis ray at another angle; therefore, raw projection data at one angle can be thought of as an ensemble of central-axis rays collected from a small arc equal to collimator aperture. Thus, fine angular sampling can compensate for collimator blurring. By using sampling pitch of less than half the collimator aperture angle, compensation was performed by subtracting the weighted sum of the projection data from the raw projection data. Collimator geometry and detector rotation radius determined the weighting function. A cylindrical phantom with four different-sized rods and torso phantom for Tl-201 cardiac SPECT simulation were used for evaluation. Aperture angle of the collimator was 7 degrees. Projection sampling pitch was 2 degrees. In both phantom studies, the proposed method showed improvement in contrast and reduction of partial volume effect, thereby indicating that the proposed method can compensate adequately for image blurring caused by collimator aperture.
{"title":"Collimator blurring reduction method using fine angular sampling projection data in SPECT","authors":"N. Motomura, K. Nambu, A. Kojima, S. Tomiguchi, K. Ogawa","doi":"10.1109/NSSMIC.2001.1009246","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1009246","url":null,"abstract":"Due to the collimator aperture, the spatial resolution of SPECT data varies with source-to-detector distance. Since radius of detector rotation is bigger when scanning larger patients, the spatial resolution is degraded in these cases. Emitted gamma rays travel not only along the central axis of the collimator hole but also off-axis due to collimator aperture. However, an off-axis ray at one angle would be a central-axis ray at another angle; therefore, raw projection data at one angle can be thought of as an ensemble of central-axis rays collected from a small arc equal to collimator aperture. Thus, fine angular sampling can compensate for collimator blurring. By using sampling pitch of less than half the collimator aperture angle, compensation was performed by subtracting the weighted sum of the projection data from the raw projection data. Collimator geometry and detector rotation radius determined the weighting function. A cylindrical phantom with four different-sized rods and torso phantom for Tl-201 cardiac SPECT simulation were used for evaluation. Aperture angle of the collimator was 7 degrees. Projection sampling pitch was 2 degrees. In both phantom studies, the proposed method showed improvement in contrast and reduction of partial volume effect, thereby indicating that the proposed method can compensate adequately for image blurring caused by collimator aperture.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121800391","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1008617
U. Bergmann, M. Ivanovic, P. Glatzel, S. Cramer
A new approach to high-resolution imaging of radio-labeled agents based on Rowland circle x-ray optics is presented. Perfect-crystal Bragg optics is widely used in x-ray research due to its high reflectivity and excellent energy resolution. The nature of Bragg reflections directly correlates energy and spatial resolution, therefore yielding good imaging properties. Applied in a one to one focusing Rowland geometry, an array of spherically bent Bragg crystals can provide a large solid angle acceptance required for efficient imaging. The potential advantage over e.g. SPECT is twofold. First, focusing optics provides a 'virtual pinhole' which can effectively be inside the object under investigation and does not suffer from edge effects and scattering. Second, Bragg optics has an energy resolution of a few eV and discriminates against inelastic Compton scattering, a common source for image blurring. Studies using /sup 55/Fe and /sup 95m/Tc phantoms are presented, where a spatial resolution of less than 1 mm and 2 mm was achieved respectively.
{"title":"High-resolution x-ray imaging using Rowland-circle Bragg optics","authors":"U. Bergmann, M. Ivanovic, P. Glatzel, S. Cramer","doi":"10.1109/NSSMIC.2001.1008617","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008617","url":null,"abstract":"A new approach to high-resolution imaging of radio-labeled agents based on Rowland circle x-ray optics is presented. Perfect-crystal Bragg optics is widely used in x-ray research due to its high reflectivity and excellent energy resolution. The nature of Bragg reflections directly correlates energy and spatial resolution, therefore yielding good imaging properties. Applied in a one to one focusing Rowland geometry, an array of spherically bent Bragg crystals can provide a large solid angle acceptance required for efficient imaging. The potential advantage over e.g. SPECT is twofold. First, focusing optics provides a 'virtual pinhole' which can effectively be inside the object under investigation and does not suffer from edge effects and scattering. Second, Bragg optics has an energy resolution of a few eV and discriminates against inelastic Compton scattering, a common source for image blurring. Studies using /sup 55/Fe and /sup 95m/Tc phantoms are presented, where a spatial resolution of less than 1 mm and 2 mm was achieved respectively.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116723707","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1009694
Liu Jiangui, A. Fremout, P. Bruyndonckx, S. Tavernier, J. Loude, C. Morel
Avalanche photodiodes (APD) could replace photomultiplier tubes (PMT) in some areas like positron emission tomography (PET). It is therefore important to study their performance. In this study, we have tested two types of APD's, the Hamamatsu S5345W and the Perkin-Elmer C30719E. We evaluated and compared the dark current, the gain and the excess noise factor of these two APD types.
{"title":"Evaluation of different types of avalanche photo diodes from Hamamatsu and Perkin-Elmer","authors":"Liu Jiangui, A. Fremout, P. Bruyndonckx, S. Tavernier, J. Loude, C. Morel","doi":"10.1109/NSSMIC.2001.1009694","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1009694","url":null,"abstract":"Avalanche photodiodes (APD) could replace photomultiplier tubes (PMT) in some areas like positron emission tomography (PET). It is therefore important to study their performance. In this study, we have tested two types of APD's, the Hamamatsu S5345W and the Perkin-Elmer C30719E. We evaluated and compared the dark current, the gain and the excess noise factor of these two APD types.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125100106","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}
Pub Date : 2001-11-04DOI: 10.1109/NSSMIC.2001.1009281
M. Fiederle, A. Fauler, V. Babentsov, J. Franc, J. Ludwig, K. Benz
CdTe crystals had been grown by the Vertical Bridgman method with diameters from 25 mm up to 75 mm. To obtain stable growth conditions the growth rate and temperature gradient had been adjusted by in-situ temperature monitoring. Several modifications had been applied to improve crystallinity. The effort of the improvements could be demonstrated by reduction of twins and the growth of large single crystalline grains up to 40/spl times/40 mm/sup 2/. Different dopants had been applied to obtain resistivities of 5/spl times/10/sup 8/ Ohmcm up to 2/spl times/10/sup 10/ Ohmcm.
{"title":"Characterization of CdTe crystals grown by the Vertical Bridgman method","authors":"M. Fiederle, A. Fauler, V. Babentsov, J. Franc, J. Ludwig, K. Benz","doi":"10.1109/NSSMIC.2001.1009281","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1009281","url":null,"abstract":"CdTe crystals had been grown by the Vertical Bridgman method with diameters from 25 mm up to 75 mm. To obtain stable growth conditions the growth rate and temperature gradient had been adjusted by in-situ temperature monitoring. Several modifications had been applied to improve crystallinity. The effort of the improvements could be demonstrated by reduction of twins and the growth of large single crystalline grains up to 40/spl times/40 mm/sup 2/. Different dopants had been applied to obtain resistivities of 5/spl times/10/sup 8/ Ohmcm up to 2/spl times/10/sup 10/ Ohmcm.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125228760","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}
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