2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)最新文献_第8页

Absolute number of scintillation photons emitted by alpha-particles in rare gases 在稀有气体中由α粒子发射的闪烁光子的绝对数目

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008470

K. Saito, S. Sasaki, H. Tawara, E. Shibamura

{"title":"Absolute number of scintillation photons emitted by alpha-particles in rare gases","authors":"K. Saito, S. Sasaki, H. Tawara, E. Shibamura","doi":"10.1109/NSSMIC.2001.1008470","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008470","url":null,"abstract":"In order to determine absolute scintillation yields due to alpha particles in high pressure rare gases, the number of scintillation photons N/sub p/ was measured by using a VUV sensitive photodiode (PD) with a MgF/sub 2/ window and a Cs-Te photocathode with spectral quantum efficiency q/sub e/(/spl lambda/) measured as a function of wavelength /spl lambda/. The number of photoelectrons from the photocathode N/sub pe/ was measured absolutely by using charge-sensitive preamplifier calibrated in numbers of electrons. A collection efficiency F/sub ce/ at the photocathode for scintillation photons can be determined from solid angles subtended by the photocathode at a scintillation point under the condition that there is no photon reflected at surrounding wall. Then, N/sub p/ was determined from N/sub p/=N/sub pe//(Q/sub e/F/sub ce/), where Q/sub e/ is effective quantum efficiency calculated from q/sub e/(/spl lambda/) and a relative intensity I(/spl lambda/) of scintillation in rare gases at wavelength /spl lambda/. Although luminescence spectrums from rare gases emitted by radiation have been measured by many researchers, these spectrums were scarcely corrected by an efficiency of apparatus (e.g. efficiency of monochromator and scintillation detector) for /spl lambda/. In order to exactly determine the luminescence spectrums, these were also measured on our own terms. And, since it was reported that scintillation intensity from rare gases change with a pressure of rare gases, this experiments was carried out in a pressure range from 1.0/spl times/10/sup 5/ Pa to 1.0/spl times/10/sup 6/ Pa. The measurements were carried out in gaseous argon, krypton and xenon. In xenon of 1.0/spl times/10/sup 5/ Pa, N/sub p/ was measured to be 1.6/spl times/10/sup 5/.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"144 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":"115043728","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}

引用次数: 33

A simulation-based assessment of the revised NEMA NU-2 70 cm long test phantom for PET 基于模拟的修订NEMA NU-2 70厘米长的PET测试模体的评估

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008614

R. Badawi, L. Adam, R. Zimmerman

引用次数: 25

Towards epitaxial lead iodide films for X-ray digital imaging 用于x射线数字成像的外延碘化铅薄膜

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008616

L. Fornaro, E. Saucedo, L. Mussio, A. Gancharov

{"title":"Towards epitaxial lead iodide films for X-ray digital imaging","authors":"L. Fornaro, E. Saucedo, L. Mussio, A. Gancharov","doi":"10.1109/NSSMIC.2001.1008616","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008616","url":null,"abstract":"Lead iodide purified by repeated evaporation was used for growing films by the physical vapor deposition method. Purity and stoichiometry of the starting material were determined by ICP and wet techniques. Films were grown onto glass substrates 2\"/spl times/2\" in size with palladium as the rear electrode. Lead iodide films were grown by evaporating the starting material at 460/spl deg/C in high purity Ar atmosphere (600 mmHg) during 1 to 4 days, depending on the film thickness. The substrate temperature was prefixed from 200 to 250/spl deg/C. Film thickness was measured by transmission of 59.5 keV radiation from /sup 241/Am giving values from 35 to 50 /spl mu/m (5%). Optical microscopy was performed to the films for determining crystallinity and grain size. Films were characterized by X-ray diffraction and texture was calculated as [/spl Sigma/I [001]]/[/spl Sigma/I (h k l)]. Correlations between grain size, crystallinity and growth preferred orientation with the c axis perpendicular to the substrate with substrate temperature were confirmed. Epitaxy of the films strongly increases with substrate temperature, and films with texture of about 90% were obtained. Correlation between starting material purity and stoichiometry with epitaxial growth were also found. For measuring electrical and X-ray response properties detectors were assembled by front palladium thermal deposition, palladium wire attachment and acrylic encapsulation. Resistivities of 5/spl times/10/sup 14/ /spl Omega/.cm and current densities of 5 pA/cm/sup 2/ at 30 V were obtained. X-ray film response was checked by irradiating with an X-ray beam, giving a linear response with exposure rate and sensitivities of about 0.35 /spl mu/C/R.cm/sup 2/. Again a correlation between electrical properties with the substrate temperature and epitaxial growth was confirmed. Finally, results were compared with previous ones for the same and alternative materials.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"32 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":"117041736","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}

引用次数: 31

Single electron transistor for cryogenic detector read-out 单电子晶体管低温检测器读出

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1009674

J. Kawarabayashi, T. Kadoi, K.-I. Watanabe, A. Uritani, T. Iguchi

引用次数: 2

A scintillating fiber tracker with high time resolution for high-rate experiments 用于高速率实验的高时间分辨率闪烁光纤跟踪器

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008519

S. Horikawa, I. Daito, N. Doshita, N. Horikawa, T. Iwata, K. Kondo, Y. Miyachi, N. Takabayashi, T. Toeda, S. Torimitsu, A. Gorin, I. Manuilov, A. Riazantsev, T. Hasegawa, T. Matsuda, K. Kuroda

引用次数: 9

First results with a novel X-ray source for dual energy angiography 首次结果与一种新的x射线源双能量血管造影

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008650

G. Baldazzi, D. Bollini, E. Celesti, M. Gambaccini, M. Gombia, C. Labanti, A. Taibi, A. Tuffanelli

{"title":"First results with a novel X-ray source for dual energy angiography","authors":"G. Baldazzi, D. Bollini, E. Celesti, M. Gambaccini, M. Gombia, C. Labanti, A. Taibi, A. Tuffanelli","doi":"10.1109/NSSMIC.2001.1008650","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008650","url":null,"abstract":"In angiographic practice an iodate contrast medium is injected in patient vessels with a catheter. The iodine is used because its linear absorption coefficient shows a K-edge at 33.169 keV. In digital subtraction angiography (DSA), some images are acquired before and during the injection of the contrast medium. The vessels' morphology is obtained by subtracting the live images from the first (mask) image. A new approach is presented where two quasimonochromatic beams, having mean energies lower and higher than the iodine K-edge, are produced simultaneously-starting from an X-ray tube-by means of a pyrolytic graphite crystal monochromator. These two thin parallel beams impinge on the phantom simulating patient vessels and are detected with solid-state array detectors. The image results as the difference between the remaining intensities of the two beams. Performance-in terms of spatial resolution, contrast and reduction of iodine concentration in an invasive perfusion medium-are presented and compared with the full spectra subtraction method in use.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"100 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":"122106252","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}

引用次数: 7

Real-time PET image reconstruction based on regularized pseudo-inverse of the system matrix 基于系统矩阵正则化伪逆的实时PET图像重建

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008678

V. Selivanov, M. Lepage, R. Lecomte

{"title":"Real-time PET image reconstruction based on regularized pseudo-inverse of the system matrix","authors":"V. Selivanov, M. Lepage, R. Lecomte","doi":"10.1109/NSSMIC.2001.1008678","DOIUrl":"https://doi.org/10.1109/NSSMIC.2001.1008678","url":null,"abstract":"The feasibility of tomographic image reconstruction by projection data filtering based on the singular value decomposition of the system matrix has recently been demonstrated in high-resolution animal positron emission tomography (PET). A regularization methodology involving truncation of the singular value spectrum based on the systematic spatial resolution analysis has been proposed and successfully applied. In the present paper, we show how realtime image reconstruction can be achieved using the regularized pseudo-inverse of the system matrix. An update of the current image estimate can be obtained using one column of the regularized pseudo-inverse matrix to account for the next registered event, thus allowing, in principle, for instant visualization of the radioactivity distribution while the object is still being scanned. Computed estimates converge to the minimum-norm least-squares solution of the regularized inverse problem when sufficient total counts are acquired to fulfill the assumption of the normal data error distribution. The computing expenses for image updating to account for the next registered event depend only on the total number of pixels in the discrete image representation. Data storage requirements are discussed. Limited angle tomography and non-traditional detection geometry may be handled using the described image reconstruction approach as well. The proposed method was tested with the list-mode PET data.","PeriodicalId":159123,"journal":{"name":"2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)","volume":"143 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":"122249510","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}

引用次数: 7

Front-end electronics for the silicon partition of the Phobos detector at RHIC RHIC火卫一探测器硅隔板的前端电子器件

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008413

M. Plesko, J. Fitch, D. Ross, C. Gomes, P. Kulinich, H. Pernegger, P. Sarin, B. Wadsowrth

引用次数: 5

A high luminosity position sensitive neutron detector for residual stress measurements 用于残余应力测量的高光度位置灵敏中子探测器

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008463

M. Moon, Changhee Lee, V. Em, H. Kang, U. Nam, A. Gabriel

引用次数: 11

Test of silicon hybrid pixel detector in 15 GeV electron beam 硅混合像素探测器在15gev电子束中的测试

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310) Pub Date : 2001-11-04 DOI: 10.1109/NSSMIC.2001.1008516

W. Caskey, G. Grim, R. Lander, D. Pellett, J.R. Smith, T. Wilkes

引用次数: 1