Pub Date : 2000-10-20DOI: 10.1109/NSSMIC.2000.949161
A. Weisenberger, F. Barbosa, T. D. Green, R. Hoefer, C. Keppel, B. Kross, S. Majewski, V. Popov, R. Wojcik, D. Wymer
Jefferson Lab, Hampton University and the Riverside Regional Medical Center are collaborating in a clinical study employing a dual modality imaging system utilizing scintimammography and digital radiography. The purpose of the study is to obtain clinical data on the reliability of scintimammography in predicting the malignancy of suspected breast lesions with the ultimate goal to reduce the number of false positives associated with conventional X-ray mammography. The scintimammography gamma camera is a custom built mini gamma camera with an active area of 5.3 cm/spl times/5.3 cm based on a 2/spl times/2 array of Hamamatsu R7600-C8 position sensitive photomultiplier tubes. The spatial resolution of the gamma camera at the collimator surface is <4 mm FWHM and the sensitivity is 4000 cps/mCi. Preliminary results are that of the six cases that indicated a lesion with high uptake of the MiraLuma (/sup 99m/Tc-sestamibi) five were positive for cancer. Out of a total of 25 patients in the study, all cases negative for MiraLuma uptake were confirmed negative via the biopsy pathology. The scintimammography results indicate that the lesions become visible with the mini gamma camera within 3 minutes post injection of MiraLuma.
杰斐逊实验室、汉普顿大学和河滨地区医疗中心正在合作进行一项临床研究，该研究采用了利用胶片摄影和数字放射摄影的双模成像系统。本研究的目的是获得关于乳腺x线摄影在预测可疑乳腺病变恶性程度方面的可靠性的临床数据，最终目的是减少与传统x线乳房x线摄影相关的假阳性数量。扫描成像伽马相机是一种定制的迷你伽马相机，其有效面积为5.3 cm/spl倍/5.3 cm，基于Hamamatsu R7600-C8位置敏感光电倍增管的2/spl倍/2阵列。准直仪表面的空间分辨率<4 mm FWHM，灵敏度为4000 cps/mCi。初步结果显示，在6例显示MiraLuma (/sup 99m/Tc-sestamibi)高摄取病变的病例中，5例为癌症阳性。在该研究的25例患者中，所有MiraLuma摄取阴性的病例都通过活检病理证实为阴性。扫描结果显示，在注射MiraLuma后3分钟内，迷你伽马相机可以看到病变。
{"title":"A combined scintimammography/stereotactic core biopsy digital X-ray system","authors":"A. Weisenberger, F. Barbosa, T. D. Green, R. Hoefer, C. Keppel, B. Kross, S. Majewski, V. Popov, R. Wojcik, D. Wymer","doi":"10.1109/NSSMIC.2000.949161","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.949161","url":null,"abstract":"Jefferson Lab, Hampton University and the Riverside Regional Medical Center are collaborating in a clinical study employing a dual modality imaging system utilizing scintimammography and digital radiography. The purpose of the study is to obtain clinical data on the reliability of scintimammography in predicting the malignancy of suspected breast lesions with the ultimate goal to reduce the number of false positives associated with conventional X-ray mammography. The scintimammography gamma camera is a custom built mini gamma camera with an active area of 5.3 cm/spl times/5.3 cm based on a 2/spl times/2 array of Hamamatsu R7600-C8 position sensitive photomultiplier tubes. The spatial resolution of the gamma camera at the collimator surface is <4 mm FWHM and the sensitivity is 4000 cps/mCi. Preliminary results are that of the six cases that indicated a lesion with high uptake of the MiraLuma (/sup 99m/Tc-sestamibi) five were positive for cancer. Out of a total of 25 patients in the study, all cases negative for MiraLuma uptake were confirmed negative via the biopsy pathology. The scintimammography results indicate that the lesions become visible with the mini gamma camera within 3 minutes post injection of MiraLuma.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132531214","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.950113
K. Erlandsson, D. Visvikis, W. Waddington, I. Cullum, P. Jarritt, L. S. Polowsky
In dynamic SPECT studies with short acquisition times per time-frame, data with very low-statistics is obtained. For such cases standard iterative reconstruction algorithms based on multiplicative correction factors, automatically including a non-negativity constraint, might not be Ideal. The AB-EMML algorithm allows the user to include prior information on the upper and lower bounds for the image values. We have used this algorithm with a negative lower bound for reconstruction of low-statistics SPECT data in order to allow for negative image values. Our results show that this method can preserve quantitative accuracy at low count levels, where standard methods produces biased values. Furthermore, the noise is much more uniformly distributed-lower in high intensity regions and higher in low intensity regions. The convergence is generally slower, but faster in cold regions.
{"title":"Low-statistics reconstruction with AB-EMML","authors":"K. Erlandsson, D. Visvikis, W. Waddington, I. Cullum, P. Jarritt, L. S. Polowsky","doi":"10.1109/NSSMIC.2000.950113","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.950113","url":null,"abstract":"In dynamic SPECT studies with short acquisition times per time-frame, data with very low-statistics is obtained. For such cases standard iterative reconstruction algorithms based on multiplicative correction factors, automatically including a non-negativity constraint, might not be Ideal. The AB-EMML algorithm allows the user to include prior information on the upper and lower bounds for the image values. We have used this algorithm with a negative lower bound for reconstruction of low-statistics SPECT data in order to allow for negative image values. Our results show that this method can preserve quantitative accuracy at low count levels, where standard methods produces biased values. Furthermore, the noise is much more uniformly distributed-lower in high intensity regions and higher in low intensity regions. The convergence is generally slower, but faster in cold regions.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115685697","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.950109
Mehmet Yavuz, J. Fessler
Most PET scans are compensated for accidental coincidence (AC) events by real-time subtraction of delayed-window coincidences. Real time subtraction of delayed coincidences compensates for the average of AC events, but also destroys the Poisson statistics. Moreover, negative values result during the real-time subtraction which would cause conventional penalized maximum likelihood algorithms to diverge, and setting these negative values to zero introduces a systematic positive bias. The authors have previously developed and compared two new methods for reconstructing transmission scans from randoms precorrected measurements: one based on a "shifted Poisson" (SP) model, and the other based on saddle-point (SD) approximations. Simulations and experimental phantom studies of transmission scans showed that both SP and SD methods lead to significantly lower variance than the conventional maximum likelihood methods (based on the ordinary Poisson (OF) model). The authors have now extended these methods to emission scans. In situations like 3D PET emission scans (with low counts per ray but many total counts and high randoms rates), they show that the proposed methods not only avoid the systematic positive bias of OP method but also lead to significantly lower variance. The new methods offer improved image reconstruction in PET through more realistic statistical modeling, yet with negligible increase in computation over the conventional OP method.
{"title":"Maximum likelihood emission image reconstruction for randoms-precorrected PET scans","authors":"Mehmet Yavuz, J. Fessler","doi":"10.1109/NSSMIC.2000.950109","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.950109","url":null,"abstract":"Most PET scans are compensated for accidental coincidence (AC) events by real-time subtraction of delayed-window coincidences. Real time subtraction of delayed coincidences compensates for the average of AC events, but also destroys the Poisson statistics. Moreover, negative values result during the real-time subtraction which would cause conventional penalized maximum likelihood algorithms to diverge, and setting these negative values to zero introduces a systematic positive bias. The authors have previously developed and compared two new methods for reconstructing transmission scans from randoms precorrected measurements: one based on a \"shifted Poisson\" (SP) model, and the other based on saddle-point (SD) approximations. Simulations and experimental phantom studies of transmission scans showed that both SP and SD methods lead to significantly lower variance than the conventional maximum likelihood methods (based on the ordinary Poisson (OF) model). The authors have now extended these methods to emission scans. In situations like 3D PET emission scans (with low counts per ray but many total counts and high randoms rates), they show that the proposed methods not only avoid the systematic positive bias of OP method but also lead to significantly lower variance. The new methods offer improved image reconstruction in PET through more realistic statistical modeling, yet with negligible increase in computation over the conventional OP method.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123097437","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.949381
T.J. Jeon, H. Kim, J. Bong, J. Lee, M. Kim, H.S. Yoo
RBC blood pool SPECT has been used to diagnose focal liver lesions such as hemangioma because of its high specificity. However, its low spatial resolution is a major limitation. Recently, ordered subset expectation maximization (OSEM) has been introduced to obtain tomographic images for clinical application. The authors compared this new modified iterative reconstruction method with conventional filtered back projection (FBP) in the imaging of liver hemangioma. Sixty four projection data were acquired using a dual head gamma camera in 25 patients with cavernous hemangioma of the liver, and this raw data was transferred to a LINUX based personal computer. After the replacement of the header file as an interfile, OSEM was performed under various conditions of subsets (1,2,4,8,16, and 32) and iteration numbers (1,2,4,8, and 16) to obtain the best setting for liver imaging, which in the authors' investigation was considered to be 4 iterations and 16 subsets. After this process, all the images processed by FBP and OSEM, in the same cases, were evaluated by 3 experts. According to a blind review of 28 lesions, OSEM images revealed at least same or better qualities than FBP in nearly all cases. Although there was no significant difference in the detection of large lesions (67.9%), 5 small lesions (17.9%) were detected by OSEM only. However, both techniques failed to depict 4 cases of small lesions (14.3%). In conclusion, OSEM revealed better contrast and definition in the depiction of liver hemangioma, and a higher sensitivity in the detection of small lesions. Furthermore, this reconstruction method didn't require a higher computer system or protracted reconstruction time, therefore, OSEM offers a good method that can be applied to RBC blood pool SPECT for the diagnosis of liver hemangioma.
{"title":"Imaging of a focal liver lesion using ordered subset expectation maximization technique","authors":"T.J. Jeon, H. Kim, J. Bong, J. Lee, M. Kim, H.S. Yoo","doi":"10.1109/NSSMIC.2000.949381","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.949381","url":null,"abstract":"RBC blood pool SPECT has been used to diagnose focal liver lesions such as hemangioma because of its high specificity. However, its low spatial resolution is a major limitation. Recently, ordered subset expectation maximization (OSEM) has been introduced to obtain tomographic images for clinical application. The authors compared this new modified iterative reconstruction method with conventional filtered back projection (FBP) in the imaging of liver hemangioma. Sixty four projection data were acquired using a dual head gamma camera in 25 patients with cavernous hemangioma of the liver, and this raw data was transferred to a LINUX based personal computer. After the replacement of the header file as an interfile, OSEM was performed under various conditions of subsets (1,2,4,8,16, and 32) and iteration numbers (1,2,4,8, and 16) to obtain the best setting for liver imaging, which in the authors' investigation was considered to be 4 iterations and 16 subsets. After this process, all the images processed by FBP and OSEM, in the same cases, were evaluated by 3 experts. According to a blind review of 28 lesions, OSEM images revealed at least same or better qualities than FBP in nearly all cases. Although there was no significant difference in the detection of large lesions (67.9%), 5 small lesions (17.9%) were detected by OSEM only. However, both techniques failed to depict 4 cases of small lesions (14.3%). In conclusion, OSEM revealed better contrast and definition in the depiction of liver hemangioma, and a higher sensitivity in the detection of small lesions. Furthermore, this reconstruction method didn't require a higher computer system or protracted reconstruction time, therefore, OSEM offers a good method that can be applied to RBC blood pool SPECT for the diagnosis of liver hemangioma.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127052696","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.949165
R.Z. Stodilka, S. Glick
The precision of quantitative analysis in hybrid PET is affected by the spatial sensitivity profile of the imaging system and by patient attenuation. Dual- and triple-head (2H and 3H, respectively) systems have different sensitivity profiles: the 2H profile being triangular and centrally peaked, whereas the 3H configuration tends to concentrate sensitivity in the peripheral field-of-view (FOV). The authors quantify how the degradation in performance of an estimation task is related to the joint action of the system sensitivity profile and patient attenuation. Their analysis involved ideal-observer models of performance in non-linear tasks involving the simultaneous (maximum-likelihood) estimation of the amplitude, size, and location of a focal lesion in a torso-sized attenuator, as well as the attenuator's background activity. The hybrid-PET system simulated was the Marconi IRIX, operating in either 2H or 3H coincidence mode. The 3H configuration had more than a two-fold greater sensitivity across the entire field of view than the 2H; however, the 3H outperformed the 2H only in the peripheral FOV. Task performance was relatively constant across the FOV for the 2H configuration because its sensitivity profile tended to mitigate count loss due to attenuation.
{"title":"Comparison of dual- and triple-head hybrid PET systems using estimation task performance","authors":"R.Z. Stodilka, S. Glick","doi":"10.1109/NSSMIC.2000.949165","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.949165","url":null,"abstract":"The precision of quantitative analysis in hybrid PET is affected by the spatial sensitivity profile of the imaging system and by patient attenuation. Dual- and triple-head (2H and 3H, respectively) systems have different sensitivity profiles: the 2H profile being triangular and centrally peaked, whereas the 3H configuration tends to concentrate sensitivity in the peripheral field-of-view (FOV). The authors quantify how the degradation in performance of an estimation task is related to the joint action of the system sensitivity profile and patient attenuation. Their analysis involved ideal-observer models of performance in non-linear tasks involving the simultaneous (maximum-likelihood) estimation of the amplitude, size, and location of a focal lesion in a torso-sized attenuator, as well as the attenuator's background activity. The hybrid-PET system simulated was the Marconi IRIX, operating in either 2H or 3H coincidence mode. The 3H configuration had more than a two-fold greater sensitivity across the entire field of view than the 2H; however, the 3H outperformed the 2H only in the peripheral FOV. Task performance was relatively constant across the FOV for the 2H configuration because its sensitivity profile tended to mitigate count loss due to attenuation.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"220 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127189050","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.949048
C.M.H. Chen, S. E. Boggs, A. Bolotnikov, W. R. Cook, Fiona A. Harrison, Steven M. Schindler
In this paper, we describe our study of charge-sharing events in CdZnTe detectors being developed for the HEFT telescope. We specify the detector design, and discuss an experiment we have performed to investigate charge sharing between pixels. We have also developed a numerical model to study the charge transport in the detector. It emulates the physical processes of charge transport within the CdZnTe crystal, especially the process of drift. We discuss this numerical model of the detector in detail. With our numerical model, we are able to reproduce the general features of the charge-sharing events. We have found that the amount of charge loss is very sensitive to the surface /spl mu//spl tau/, the product of charge mobility and trapping time, of CdZnTe; we present estimates of (/spl mu//spl tau/)/sub surface/ from our model. Further work will focus on more detailed analysis of diffusion, in order to gain a complete understanding of these charge-sharing events in CdZnTe pixel detectors.
{"title":"Numerical modelling of charge-sharing in CdZnTe pixel detectors","authors":"C.M.H. Chen, S. E. Boggs, A. Bolotnikov, W. R. Cook, Fiona A. Harrison, Steven M. Schindler","doi":"10.1109/NSSMIC.2000.949048","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.949048","url":null,"abstract":"In this paper, we describe our study of charge-sharing events in CdZnTe detectors being developed for the HEFT telescope. We specify the detector design, and discuss an experiment we have performed to investigate charge sharing between pixels. We have also developed a numerical model to study the charge transport in the detector. It emulates the physical processes of charge transport within the CdZnTe crystal, especially the process of drift. We discuss this numerical model of the detector in detail. With our numerical model, we are able to reproduce the general features of the charge-sharing events. We have found that the amount of charge loss is very sensitive to the surface /spl mu//spl tau/, the product of charge mobility and trapping time, of CdZnTe; we present estimates of (/spl mu//spl tau/)/sub surface/ from our model. Further work will focus on more detailed analysis of diffusion, in order to gain a complete understanding of these charge-sharing events in CdZnTe pixel detectors.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127240927","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.949016
R. Abe, H. Aihara, G. Alimonti, Y. Asano, A. Bakich, E. Banas, A. Bozek, T. Browder, J. Dragic, C. Everton, C. Fukunaga, A. Gordon, H. Guler, J. Haba, K. Hara, T. Hara, N. Hastings, M. Hazumi, E. Heenan, T. Eiguchi, T. Hojo, H. Ishino, G. Iwai, P. Jalocha, J. Kaneko, P. Kapusta, T. Kawasaki, K. Korotuschenko, J. Lange, Y. Li, D. Marlow, T. Matsubara, H. Miyake, L. Moffitt, G. Moloney, S. Mori, T. Nakadaira, T. Nakamura, Z. Natkaniec, S. Okuno, S. Olsen, W. Ostrowicz, H. Palka, L. Peak, M. Różańska, J. Ryuko, M. Sevior, K. Shimada, K. Sumisawa, S. Stanič, R. Stock, S. Swain, H. Tagomori, H. Tajima, S. Takahashi, F. Takasaki, N. Tamura, J. Tanaka, M. Tanaka, G. Taylor, T. Tomura, K. Trabelsi, T. Tsuboyama, Y. Tsujita, G. Varner, K. Varvell, H. Yamamoto, Y. Watanabe, Y. Yamada, M. Yokoyama, H. Zhao, D. Žontar
The performance of the Silicon Vertex Detector (SVD) in the Belle experiment is reviewed based on 6.8 fb/sup -1/ of data taken between October 1999 and July 2000. The main purpose of the SVD is to make precise measurements of the B decay vertex position, which are essential for the observation of CP asymmetries. Excellent vertex resolution and a good detection efficiency are required for the SVD. Basic performance parameters such as signal pulse height, noise, strip yield and intrinsic resolution are reported. The SVD performance parameters which are directly related to physics analysis such as track matching efficiency, impact parameter resolution and vertex resolution are also shown.
{"title":"Performance of the Belle silicon vertex detector","authors":"R. Abe, H. Aihara, G. Alimonti, Y. Asano, A. Bakich, E. Banas, A. Bozek, T. Browder, J. Dragic, C. Everton, C. Fukunaga, A. Gordon, H. Guler, J. Haba, K. Hara, T. Hara, N. Hastings, M. Hazumi, E. Heenan, T. Eiguchi, T. Hojo, H. Ishino, G. Iwai, P. Jalocha, J. Kaneko, P. Kapusta, T. Kawasaki, K. Korotuschenko, J. Lange, Y. Li, D. Marlow, T. Matsubara, H. Miyake, L. Moffitt, G. Moloney, S. Mori, T. Nakadaira, T. Nakamura, Z. Natkaniec, S. Okuno, S. Olsen, W. Ostrowicz, H. Palka, L. Peak, M. Różańska, J. Ryuko, M. Sevior, K. Shimada, K. Sumisawa, S. Stanič, R. Stock, S. Swain, H. Tagomori, H. Tajima, S. Takahashi, F. Takasaki, N. Tamura, J. Tanaka, M. Tanaka, G. Taylor, T. Tomura, K. Trabelsi, T. Tsuboyama, Y. Tsujita, G. Varner, K. Varvell, H. Yamamoto, Y. Watanabe, Y. Yamada, M. Yokoyama, H. Zhao, D. Žontar","doi":"10.1109/NSSMIC.2000.949016","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.949016","url":null,"abstract":"The performance of the Silicon Vertex Detector (SVD) in the Belle experiment is reviewed based on 6.8 fb/sup -1/ of data taken between October 1999 and July 2000. The main purpose of the SVD is to make precise measurements of the B decay vertex position, which are essential for the observation of CP asymmetries. Excellent vertex resolution and a good detection efficiency are required for the SVD. Basic performance parameters such as signal pulse height, noise, strip yield and intrinsic resolution are reported. The SVD performance parameters which are directly related to physics analysis such as track matching efficiency, impact parameter resolution and vertex resolution are also shown.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123439751","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.949924
I. Adam, R. Aleksan, D. Aston, M. Benkebil, D. Bernard, G. Bonneaud, F. Brochard, D. Brown, P. Bourgeois, J. Chauveau, J. Cohen-Tanugi, M. Convery, G. De Domenico, A. de Lesquen, S. Emery, S. Ferrag, A. Gaidot, Terece L. Turton, G. Hamel de Monchenault, C. Hast, A. Hoecker, R. Kadel, J. Kadyk, M. Krishnamurthy, H. Lacker, G. London, A. Lu, A. Lutz, G. Lynch, G. Mancinelli, F. Martinez-Vidal, N. Mayer, B. Meadows, D. Muller, S. Plaszczynski, M. Pripstien, B. Ratcliff, L. Roos, E. Roussot, M.-H. Schyne, J. Schwiening, V. Shelkov, M. Sokoloff, S. Spainer, J. Stark, A. Telnov, C. Thiebaux, G. Vasileiadis, G. Vasseur, J. Va’vra, M. Verderi, W. Wenzel, R. Wilson, G. Wormser, C. Yéche, S. Yellin, M. Zito
The DIRC (acronym for Detection of Internally Reflected Cherenkov (light)) is the ring imaging Cherenkov detector of the BABAR detector at the PEP-II ring of SLAC. It provides the identification of pions, kaons and protons for momenta up to 4 GeV/c with high efficiency. This is needed to reconstruct CP-violating B-decay final states and to provide B-meson flavour tagging for time dependent asymmetry measurements. The DIRC radiators consists of long rectangular bars made of synthetic fused silica and the photon detector is a water tank equipped with an array of 10.752 conventional photomultipliers. At the end of the year 2000 BABAR has recorded about 22 million B~B pairs reaching the design luminosity of L=3/spl middot/10/sup 33//cm/sup 2/s. The ability to keep the beam background level low at highest collision rates and the long term reliability of the DIRC components during continuous data taking are requirements of BABAR to accomplish its physics program.
{"title":"Operation of the Cherenkov detector DIRC of BABAR at high luminosity","authors":"I. Adam, R. Aleksan, D. Aston, M. Benkebil, D. Bernard, G. Bonneaud, F. Brochard, D. Brown, P. Bourgeois, J. Chauveau, J. Cohen-Tanugi, M. Convery, G. De Domenico, A. de Lesquen, S. Emery, S. Ferrag, A. Gaidot, Terece L. Turton, G. Hamel de Monchenault, C. Hast, A. Hoecker, R. Kadel, J. Kadyk, M. Krishnamurthy, H. Lacker, G. London, A. Lu, A. Lutz, G. Lynch, G. Mancinelli, F. Martinez-Vidal, N. Mayer, B. Meadows, D. Muller, S. Plaszczynski, M. Pripstien, B. Ratcliff, L. Roos, E. Roussot, M.-H. Schyne, J. Schwiening, V. Shelkov, M. Sokoloff, S. Spainer, J. Stark, A. Telnov, C. Thiebaux, G. Vasileiadis, G. Vasseur, J. Va’vra, M. Verderi, W. Wenzel, R. Wilson, G. Wormser, C. Yéche, S. Yellin, M. Zito","doi":"10.1109/NSSMIC.2000.949924","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.949924","url":null,"abstract":"The DIRC (acronym for Detection of Internally Reflected Cherenkov (light)) is the ring imaging Cherenkov detector of the BABAR detector at the PEP-II ring of SLAC. It provides the identification of pions, kaons and protons for momenta up to 4 GeV/c with high efficiency. This is needed to reconstruct CP-violating B-decay final states and to provide B-meson flavour tagging for time dependent asymmetry measurements. The DIRC radiators consists of long rectangular bars made of synthetic fused silica and the photon detector is a water tank equipped with an array of 10.752 conventional photomultipliers. At the end of the year 2000 BABAR has recorded about 22 million B~B pairs reaching the design luminosity of L=3/spl middot/10/sup 33//cm/sup 2/s. The ability to keep the beam background level low at highest collision rates and the long term reliability of the DIRC components during continuous data taking are requirements of BABAR to accomplish its physics program.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125669616","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.949252
D.S.A.P. Freitas, J. Veloso, J. D. dos Santos, C. Conde
A study by numerical simulation of the performance of 8 different microstrip plate (MSP) chambers filled with xenon at the pressure of 10/sup 5/ Pa is carried out. The anode width is fixed at 10 /spl mu/m but the cathode width ranges from 80 to 320 /spl mu/m with variable anode-to-cathode distances (from 10 to 55 /spl mu/m). Simulation results are presented for the avalanche multiplication factors at a certain drift position and gains for the various geometries. The amount of optical positive feedback is also estimated for the various geometries, since this is a determinant factor for the use of a CsI-covered MSP chamber, as a VUV photosensor for detection of the scintillation light of a Gas Proportional Scintillation Counter. For this purpose, the best MSP geometry studied is the one with 160 /spl mu/m cathodes and cathode-to-anode gaps of 55 /spl mu/m.
{"title":"A comparative study of different microstrip plate geometries for CsI-based UV photosensors working in a reflective mode","authors":"D.S.A.P. Freitas, J. Veloso, J. D. dos Santos, C. Conde","doi":"10.1109/NSSMIC.2000.949252","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.949252","url":null,"abstract":"A study by numerical simulation of the performance of 8 different microstrip plate (MSP) chambers filled with xenon at the pressure of 10/sup 5/ Pa is carried out. The anode width is fixed at 10 /spl mu/m but the cathode width ranges from 80 to 320 /spl mu/m with variable anode-to-cathode distances (from 10 to 55 /spl mu/m). Simulation results are presented for the avalanche multiplication factors at a certain drift position and gains for the various geometries. The amount of optical positive feedback is also estimated for the various geometries, since this is a determinant factor for the use of a CsI-covered MSP chamber, as a VUV photosensor for detection of the scintillation light of a Gas Proportional Scintillation Counter. For this purpose, the best MSP geometry studied is the one with 160 /spl mu/m cathodes and cathode-to-anode gaps of 55 /spl mu/m.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116355479","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 : 2000-10-15DOI: 10.1109/NSSMIC.2000.949926
G. Borreani, N. Cartiglia, R. Cester, F. Daudo, A. de Capoa, M. D. de Oliveira, F. Marchetto, D. Maurizio, N. Pastrone
The Pierre Auger Observatory will study cosmic rays with energy exceeding 10/sup 19/ eV. The experiment will measure properties of Extensive Air Showers with a hybrid detector consisting of a surface array and an atmospheric fluorescence telescope. This paper presents the characteristics and performance of the optical system for the fluorescence detector prototype. The system adopts a Schmidt camera design with a diaphragm to remove coma aberration. A large spherical mirror (approximately 3.6 m/spl times/3.6 m, with curvature radius 3.47 m), segmented in 49 trapezoidal elements, is supported by a mechanical structure, where segments are positioned on the meridians of the spherical cap. At the diaphragm, an absorption filter is installed to preferentially transmit the nitrogen fluorescence light. The construction technique, image characteristics and results of tests performed on the system are discussed.
{"title":"The fluorescence detector prototype for the Auger project: mechanical structure, optical system and filter","authors":"G. Borreani, N. Cartiglia, R. Cester, F. Daudo, A. de Capoa, M. D. de Oliveira, F. Marchetto, D. Maurizio, N. Pastrone","doi":"10.1109/NSSMIC.2000.949926","DOIUrl":"https://doi.org/10.1109/NSSMIC.2000.949926","url":null,"abstract":"The Pierre Auger Observatory will study cosmic rays with energy exceeding 10/sup 19/ eV. The experiment will measure properties of Extensive Air Showers with a hybrid detector consisting of a surface array and an atmospheric fluorescence telescope. This paper presents the characteristics and performance of the optical system for the fluorescence detector prototype. The system adopts a Schmidt camera design with a diaphragm to remove coma aberration. A large spherical mirror (approximately 3.6 m/spl times/3.6 m, with curvature radius 3.47 m), segmented in 49 trapezoidal elements, is supported by a mechanical structure, where segments are positioned on the meridians of the spherical cap. At the diaphragm, an absorption filter is installed to preferentially transmit the nitrogen fluorescence light. The construction technique, image characteristics and results of tests performed on the system are discussed.","PeriodicalId":445100,"journal":{"name":"2000 IEEE Nuclear Science Symposium. Conference Record (Cat. No.00CH37149)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122392480","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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