Pub Date : 2024-01-01DOI: 10.1088/1748-0221/19/01/P01004
Zheng Chen, Zhen Tao, A. Yolbarsop, Hong Li, Yuan Zhang, Wentan Yan, Xianhao Rao, Shunrong Ren, Furen Tian, W. Mao, Zian Wei, Zixi Liu, Chu Zhou, A. Liu, Tao Lan, Jinlin Xie, Hai-ying Zhou, X. Wen, Hai Wang, Zhuang Ge, C. Xiao, Weixing Ding, Wandong Liu
Since the establishment of the eddy current diagnostic system within the Keda Torus eXperiment (KTX) device, it has unveiled many applications. Recent developments have introduced innovative data analysis techniques alongside compelling experimental results, underscoring the necessity for a comprehensive summary of the system's data analysis approaches and broad applications. Notable features of the system encompass exceptional precision, the ability to encompass shell currents on the entirety of the closed boundary, vector detection of shell currents, and measurement of diverse physical quantities. In terms of data analysis methodologies, meticulous scrutiny of the null field region is conducted, and we reveal a distinctive characteristic within the complex shell current signals, namely the asymmetry of the amplitudes of ±n Fourier coefficients. Moreover, the Hodge decomposition emerges as a pivotal technique, allowing for the distinctive separation of shell currents into three orthogonal components based on their distinct spatial topological properties. With regard to practical applications, an in-depth examination of the vector potential and magnetic helicity flux densities are presented in detail, further highlighting the far-reaching utility of the system's capabilities.
自从在 Keda Torus eXperiment（KTX）装置内建立涡流诊断系统以来，该系统已经推出了许多应用。最近的发展除了令人信服的实验结果之外，还引入了创新的数据分析技术，因此有必要对该系统的数据分析方法和广泛应用进行全面总结。该系统的显著特点包括超高精度、能够涵盖整个封闭边界的壳电流、壳电流的矢量检测以及各种物理量的测量。在数据分析方法方面，我们对空场区域进行了细致的检查，发现了复杂壳电流信号的一个显著特点，即 ±n 傅立叶系数振幅的不对称性。此外，霍奇分解是一项关键技术，可根据贝壳电流不同的空间拓扑特性，将其分为三个正交分量。在实际应用方面，详细介绍了对矢量势和磁螺旋通量密度的深入研究，进一步突出了系统功能的深远实用性。
{"title":"Data analysis methods and applications of the eddy current diagnostic system in the Keda Torus eXperiment device","authors":"Zheng Chen, Zhen Tao, A. Yolbarsop, Hong Li, Yuan Zhang, Wentan Yan, Xianhao Rao, Shunrong Ren, Furen Tian, W. Mao, Zian Wei, Zixi Liu, Chu Zhou, A. Liu, Tao Lan, Jinlin Xie, Hai-ying Zhou, X. Wen, Hai Wang, Zhuang Ge, C. Xiao, Weixing Ding, Wandong Liu","doi":"10.1088/1748-0221/19/01/P01004","DOIUrl":"https://doi.org/10.1088/1748-0221/19/01/P01004","url":null,"abstract":"Since the establishment of the eddy current diagnostic system within the Keda Torus eXperiment (KTX) device, it has unveiled many applications. Recent developments have introduced innovative data analysis techniques alongside compelling experimental results, underscoring the necessity for a comprehensive summary of the system's data analysis approaches and broad applications. Notable features of the system encompass exceptional precision, the ability to encompass shell currents on the entirety of the closed boundary, vector detection of shell currents, and measurement of diverse physical quantities. In terms of data analysis methodologies, meticulous scrutiny of the null field region is conducted, and we reveal a distinctive characteristic within the complex shell current signals, namely the asymmetry of the amplitudes of ±n Fourier coefficients. Moreover, the Hodge decomposition emerges as a pivotal technique, allowing for the distinctive separation of shell currents into three orthogonal components based on their distinct spatial topological properties. With regard to practical applications, an in-depth examination of the vector potential and magnetic helicity flux densities are presented in detail, further highlighting the far-reaching utility of the system's capabilities.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":" 9","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139393226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1088/1748-0221/19/01/C01006
N. Ogino, M. Arimoto, T. Sawano, D. Yonetoku, Hsien-chieh Shen, Takanori Sakamoto, J. Hiraga, Y. Yatsu, Tatehiro Mihara
We developed an FPGA-based high-speed readout system for a complementary metal-oxide-semiconductor (CMOS) image sensor to observe soft X-ray transients in future satellite missions, such as HiZ-GUNDAM. Our previous research revealed that the CMOS image sensor has low-energy X-ray detection capability (0.4–4 keV) and strong radiation tolerance, which satisfies the requirements of the HiZ-GUNDAM mission. However, CMOS sensors typically have small pixel sizes (e.g., ∼10 µm), resulting in large volumes of image data. GSENSE400BSI has 2048×2048 pixels, producing 6 Mbyte per frame. These large volumes of observed raw image data cannot be stored in a satellite bus system with a limited storage size. Therefore, only X-ray photon events must be extracted from the raw image data. Furthermore, the readout time of CMOS image sensors is approximately ten times faster than that of typical X-ray CCDs, requiring faster event extraction on a timescale of ∼0.1 s. To address these issues, we have developed an FPGA-based image signal processing system capable of high-speed X-ray event extraction onboard without storing raw image data. The developed compact system enabled mounting on a CubeSat mission, facilitating early in-orbit operation demonstration. Here, we present the design and results of the performance evaluation tests of the proposed FPGA-based readout system. Utilizing X-ray irradiation experiments, the results of the X-ray event extraction with the onboard and offline processing methods were consistent, validating the functionality of the proposed system.
我们为互补金属氧化物半导体（CMOS）图像传感器开发了一种基于 FPGA 的高速读出系统，用于观测未来卫星任务（如 HiZ-GUNDAM）中的软 X 射线瞬变。我们之前的研究表明，CMOS 图像传感器具有低能 X 射线探测能力（0.4-4 keV）和较强的辐射耐受性，这满足了 HiZ-GUNDAM 任务的要求。然而，CMOS 传感器的像素尺寸通常较小（如 10 微米），因此图像数据量较大。GSENSE400BSI 有 2048×2048 像素，每帧产生 6 Mbyte。这些大量的观测原始图像数据无法存储在存储容量有限的卫星总线系统中。因此，必须从原始图像数据中只提取 X 射线光子事件。此外，CMOS 图像传感器的读出时间比典型的 X 射线 CCD 快约 10 倍，这就要求以 ∼ 0.1 秒的时间尺度更快地提取事件。为了解决这些问题，我们开发了一种基于 FPGA 的图像信号处理系统，该系统能够在不存储原始图像数据的情况下在卫星上高速提取 X 射线事件。所开发的系统结构紧凑，可安装在立方体卫星任务上，便于进行早期在轨运行演示。在此，我们介绍了所提出的基于 FPGA 的读出系统的设计和性能评估测试结果。利用 X 射线辐照实验，采用星载和离线处理方法提取 X 射线事件的结果一致，验证了所提系统的功能。
{"title":"High-speed readout system of X-ray CMOS image sensor for time domain astronomy","authors":"N. Ogino, M. Arimoto, T. Sawano, D. Yonetoku, Hsien-chieh Shen, Takanori Sakamoto, J. Hiraga, Y. Yatsu, Tatehiro Mihara","doi":"10.1088/1748-0221/19/01/C01006","DOIUrl":"https://doi.org/10.1088/1748-0221/19/01/C01006","url":null,"abstract":"We developed an FPGA-based high-speed readout system for a complementary metal-oxide-semiconductor (CMOS) image sensor to observe soft X-ray transients in future satellite missions, such as HiZ-GUNDAM. Our previous research revealed that the CMOS image sensor has low-energy X-ray detection capability (0.4–4 keV) and strong radiation tolerance, which satisfies the requirements of the HiZ-GUNDAM mission. However, CMOS sensors typically have small pixel sizes (e.g., ∼10 µm), resulting in large volumes of image data. GSENSE400BSI has 2048×2048 pixels, producing 6 Mbyte per frame. These large volumes of observed raw image data cannot be stored in a satellite bus system with a limited storage size. Therefore, only X-ray photon events must be extracted from the raw image data. Furthermore, the readout time of CMOS image sensors is approximately ten times faster than that of typical X-ray CCDs, requiring faster event extraction on a timescale of ∼0.1 s. To address these issues, we have developed an FPGA-based image signal processing system capable of high-speed X-ray event extraction onboard without storing raw image data. The developed compact system enabled mounting on a CubeSat mission, facilitating early in-orbit operation demonstration. Here, we present the design and results of the performance evaluation tests of the proposed FPGA-based readout system. Utilizing X-ray irradiation experiments, the results of the X-ray event extraction with the onboard and offline processing methods were consistent, validating the functionality of the proposed system.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":" 3","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139392578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The comprehensive Research Facility for Fusion Technology(CRAFT) has been carried out since 2019 in China and as an important component of CRAFT, a negative ion-based neutral beam injection sysgem(NNBI) (200–400 keV, 2 MW) is under construction. In order to realize online diagnosis of beam uniformity, a tungsten wire calorimeter is developed. The tungsten wire calorimeter is characterized by double-layer tungsten wire mesh structure. During beam bombardment, the tungsten wire mesh is heated and emits light, a visible light camera is used to photograph the tungsten wire calorimeter. The beam profile is obtained by digitizing the light intensity distribution map. In this paper, through the thermal simulation anslysis of tungsten wire, the installation position of tungsten wire calorimeter are determined and the spatial resolution under different beam divergence are also analyzed.The tungsten wire calorimeter was tested on the beam source test platform, the light intensity distribution maps of the tungsten wire calorimeter under 15 keV–40 keV beam energy were obtained. The work above will accumulate experience for the operation of tungsten wire calorimeter for full scale beam source in the next stage, and provide technical means for the conditioning of negative beam sources.
{"title":"Preliminary experimental results of tungsten wire calorimeter for CRAFT NNBI","authors":"L. Yu, Y.Z. Xu, Y.J. Xu, X.B. Mou, L.P. Chen, X.F. Peng","doi":"10.1088/1748-0221/19/01/C01004","DOIUrl":"https://doi.org/10.1088/1748-0221/19/01/C01004","url":null,"abstract":"The comprehensive Research Facility for Fusion Technology(CRAFT) has been carried out since 2019 in China and as an important component of CRAFT, a negative ion-based neutral beam injection sysgem(NNBI) (200–400 keV, 2 MW) is under construction. In order to realize online diagnosis of beam uniformity, a tungsten wire calorimeter is developed. The tungsten wire calorimeter is characterized by double-layer tungsten wire mesh structure. During beam bombardment, the tungsten wire mesh is heated and emits light, a visible light camera is used to photograph the tungsten wire calorimeter. The beam profile is obtained by digitizing the light intensity distribution map. In this paper, through the thermal simulation anslysis of tungsten wire, the installation position of tungsten wire calorimeter are determined and the spatial resolution under different beam divergence are also analyzed.The tungsten wire calorimeter was tested on the beam source test platform, the light intensity distribution maps of the tungsten wire calorimeter under 15 keV–40 keV beam energy were obtained. The work above will accumulate experience for the operation of tungsten wire calorimeter for full scale beam source in the next stage, and provide technical means for the conditioning of negative beam sources.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":"21 S7","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1088/1748-0221/19/01/C01007
D. Hladik, J. Jakůbek, K. Sykorova, T. Cerna, D. Doubravova, M. Urban, Š. Polansky
The introduction of the new hybrid pixel detector Timepix2, as a successor to the well-known Timepix detector, has presented new opportunities for optimizing and characterizing this novel device. In this paper, we study the Timepix2 detector optimization and analyze its behavior, which enables better parameter setting for specific applications, resulting in enhanced device performance. Our newly developed equalization process, in conjunction with the device optimization, has led to significant improvements in the detector's accuracy and performance, facilitating more precise data collection and analysis. These advancements pave the way for the broader utilization of Timepix2 in numerous applications, such as space weather monitoring, X-ray diffraction, etc. Overall, our study provides valuable insights into the optimization and characterization of Timepix2, highlighting its potential as a powerful tool in various scientific, industrial and space applications.
{"title":"Optimizing and characterizing the Timepix2 hybrid pixel detector: enhancing performance and precision for scientific and industrial applications","authors":"D. Hladik, J. Jakůbek, K. Sykorova, T. Cerna, D. Doubravova, M. Urban, Š. Polansky","doi":"10.1088/1748-0221/19/01/C01007","DOIUrl":"https://doi.org/10.1088/1748-0221/19/01/C01007","url":null,"abstract":"The introduction of the new hybrid pixel detector Timepix2, as a successor to the well-known Timepix detector, has presented new opportunities for optimizing and characterizing this novel device. In this paper, we study the Timepix2 detector optimization and analyze its behavior, which enables better parameter setting for specific applications, resulting in enhanced device performance. Our newly developed equalization process, in conjunction with the device optimization, has led to significant improvements in the detector's accuracy and performance, facilitating more precise data collection and analysis. These advancements pave the way for the broader utilization of Timepix2 in numerous applications, such as space weather monitoring, X-ray diffraction, etc. Overall, our study provides valuable insights into the optimization and characterization of Timepix2, highlighting its potential as a powerful tool in various scientific, industrial and space applications.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":"32 1‐2","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1088/1748-0221/19/01/C01005
S. Owe, I. Kuvvetli, A. Zoglauer, C. Budtz-Jørgensen
This feasibility study explores the possibility of using 3D CZT drift strip detectors developed by DTU Space in a small Compton camera payload, with the primary objective of technology demonstration. We have defined a scalable mass model for the payload, comprising eight 3D CZT drift strip detectors surrounded by CsI scintillator detectors for active shielding. The payload's angular resolution, effective area, and efficiency are evaluated through simulations of far-field monochromatic point sources. The instrument's sensitivity is assessed in a low Earth orbit background environment for nuclear line and continuum emission sources. With a 3σ point source sensitivity in the order of 10-4 [ph/cm2/s], it is evident that such an instrument only allows for limited scientific goals. In-orbit simulations of bright sources are conducted, resulting in reasonable observation times for the Crab Nebula at a 5σ significance level. Furthermore, in-orbit simulations of a selection of bright gamma-ray bursts indicate the potential for observing bright transient events. The study underscores the potential of using 3D CZT drift strip detectors in Compton camera configurations but also highlights the need for a larger effective area to improve sensitivity. However, for a technology demonstration aimed at increasing the Technology Readiness Level of the 3D CZT drift strip detector, a small Compton camera configuration like the one presented in this study could be a viable solution.
{"title":"Feasibility of using 3D CZT drift strip detectors for small Compton camera space missions","authors":"S. Owe, I. Kuvvetli, A. Zoglauer, C. Budtz-Jørgensen","doi":"10.1088/1748-0221/19/01/C01005","DOIUrl":"https://doi.org/10.1088/1748-0221/19/01/C01005","url":null,"abstract":"This feasibility study explores the possibility of using 3D CZT drift strip detectors developed by DTU Space in a small Compton camera payload, with the primary objective of technology demonstration. We have defined a scalable mass model for the payload, comprising eight 3D CZT drift strip detectors surrounded by CsI scintillator detectors for active shielding. The payload's angular resolution, effective area, and efficiency are evaluated through simulations of far-field monochromatic point sources. The instrument's sensitivity is assessed in a low Earth orbit background environment for nuclear line and continuum emission sources. With a 3σ point source sensitivity in the order of 10-4 [ph/cm2/s], it is evident that such an instrument only allows for limited scientific goals. In-orbit simulations of bright sources are conducted, resulting in reasonable observation times for the Crab Nebula at a 5σ significance level. Furthermore, in-orbit simulations of a selection of bright gamma-ray bursts indicate the potential for observing bright transient events. The study underscores the potential of using 3D CZT drift strip detectors in Compton camera configurations but also highlights the need for a larger effective area to improve sensitivity. However, for a technology demonstration aimed at increasing the Technology Readiness Level of the 3D CZT drift strip detector, a small Compton camera configuration like the one presented in this study could be a viable solution.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":"55 11","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139394506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1088/1748-0221/19/01/P01008
J. Turko, R. Beyer, A. Junghans, I. Meric, S.E. Mueller, G. Pausch, H.N. Ratliff, K. Römer, S. M. Schellhammer, L. Setterdahl, S. Urlass, A. Wagner, T. Kögler
For accurate and simultaneous imaging of fast neutrons (FNs) and prompt gamma rays (PGs) produced during proton therapy, the selection of a highly performant detector material is crucial. In this work, a promising candidate material known as organic glass scintillator (OGS) is characterized for this task. To this end, a precisely-timed source of neutrons and Bremsstrahlung radiation produced by the nELBE facility was used to study the light output and neutron/gamma ray pulse shape discrimination (PSD) properties of a 1 × 1 × 20 cm3 OGS bar with double-sided readout. Furthermore, the energy, timing, and depth-of-interaction (DOI) resolutions of 1 × 1 × 10 cm3 and 1 × 1 × 20 cm3 OGS and EJ-200 bars were characterized with radioactive sources. For electron-equivalent energies above 0.5 MeVee, OGS was found to have excellent PSD capabilities (figure-of-merit above 1.27), energy resolution (below 12%), coincident time resolution (below 500 ps), and DOI resolution (below 10 mm). This work establishes the data analysis methods required for hybrid FN/PG imaging using OGS, and demonstrates the materials' excellent performance for this application.
{"title":"Characterization of organic glass scintillator bars and their potential for a hybrid neutron/gamma ray imaging system for proton radiotherapy range verification","authors":"J. Turko, R. Beyer, A. Junghans, I. Meric, S.E. Mueller, G. Pausch, H.N. Ratliff, K. Römer, S. M. Schellhammer, L. Setterdahl, S. Urlass, A. Wagner, T. Kögler","doi":"10.1088/1748-0221/19/01/P01008","DOIUrl":"https://doi.org/10.1088/1748-0221/19/01/P01008","url":null,"abstract":"For accurate and simultaneous imaging of fast neutrons (FNs) and prompt gamma rays (PGs) produced during proton therapy, the selection of a highly performant detector material is crucial. In this work, a promising candidate material known as organic glass scintillator (OGS) is characterized for this task. To this end, a precisely-timed source of neutrons and Bremsstrahlung radiation produced by the nELBE facility was used to study the light output and neutron/gamma ray pulse shape discrimination (PSD) properties of a 1 × 1 × 20 cm3 OGS bar with double-sided readout. Furthermore, the energy, timing, and depth-of-interaction (DOI) resolutions of 1 × 1 × 10 cm3 and 1 × 1 × 20 cm3 OGS and EJ-200 bars were characterized with radioactive sources. For electron-equivalent energies above 0.5 MeVee, OGS was found to have excellent PSD capabilities (figure-of-merit above 1.27), energy resolution (below 12%), coincident time resolution (below 500 ps), and DOI resolution (below 10 mm). This work establishes the data analysis methods required for hybrid FN/PG imaging using OGS, and demonstrates the materials' excellent performance for this application.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":" 43","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139393165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1088/1748-0221/19/01/P01001
Mokhtar Chmeissani, Machiel Kolstein, G. Ariño-Estrada, J. Macias-Montero, C. Puigdengoles, Jorge García
With positron emission tomography (PET), the positron of a β + emitter radioisotope annihilates with a nearby electron producing a pair of back-to-back 511 keV gamma rays that can be detected in a scanner surrounding the point source. The position of the point source is somewhere along the Line of Response (LOR) that passes through the positions where the 511 keV gammas are detected. In standard PET, an image reconstruction algorithm is used to combine these LORs into a final image. This paper presents a new tomographic imaging technique to locate the position of a β + emitting point source without using a standard PET image reconstruction algorithm. The data were collected with a Proof-of-Concept (PoC) PET scanner which has high spatial and energy resolutions. The imaging technique presented in this paper uses events where a gamma undergoes Compton scattering. The positions and energies deposited by the Compton scattered gamma define the surface of a Compton cone (CC) which is the locus of all possible positions of the point source, allowed by the Compton kinematics. The position of the same point source is also located somewhere on the LOR. Therefore, the position of the point source is defined by the 3 gammas and is given by the intersection point of the LOR and the Compton cone inside the Field of View (FOV) of the scanner. We refer to this method as CC×LOR. This new technique can locate the point source with an uncertainty of about 1 mm, after collecting a minimum of 200 CC×LOR events.
通过正电子发射断层扫描（PET），β+发射体放射性同位素的正电子与附近的电子湮灭，产生一对背对背的 511 千伏伽马射线，可在点源周围的扫描仪中检测到。点源的位置位于反应线（LOR）的某处，而反应线则穿过检测到 511 千伏伽马射线的位置。在标准正电子发射计算机断层成像技术中，图像重建算法用于将这些响应线组合成最终图像。本文介绍了一种新的断层成像技术，无需使用标准 PET 图像重建算法即可定位 β + 发射点源的位置。数据是用一台概念验证（PoC）PET 扫描仪收集的，该扫描仪具有很高的空间分辨率和能量分辨率。本文介绍的成像技术使用的是伽马发生康普顿散射的事件。康普顿散射伽马所沉积的位置和能量定义了康普顿锥（CC）的表面，而康普顿锥是康普顿运动学所允许的点源所有可能位置的位置。同一点源的位置也位于 LOR 上的某处。因此，点源的位置由 3 个伽马定义，并由扫描仪视场（FOV）内的 LOR 和康普顿锥的交点给出。我们将这种方法称为 CC×LOR。在收集了至少 200 个 CC×LOR 事件之后，这种新技术可以在不确定度约为 1 毫米的情况下确定点源的位置。
{"title":"Tracking a moving point source using triple gamma imaging","authors":"Mokhtar Chmeissani, Machiel Kolstein, G. Ariño-Estrada, J. Macias-Montero, C. Puigdengoles, Jorge García","doi":"10.1088/1748-0221/19/01/P01001","DOIUrl":"https://doi.org/10.1088/1748-0221/19/01/P01001","url":null,"abstract":"With positron emission tomography (PET), the positron of a β + emitter radioisotope annihilates with a nearby electron producing a pair of back-to-back 511 keV gamma rays that can be detected in a scanner surrounding the point source. The position of the point source is somewhere along the Line of Response (LOR) that passes through the positions where the 511 keV gammas are detected. In standard PET, an image reconstruction algorithm is used to combine these LORs into a final image. This paper presents a new tomographic imaging technique to locate the position of a β + emitting point source without using a standard PET image reconstruction algorithm. The data were collected with a Proof-of-Concept (PoC) PET scanner which has high spatial and energy resolutions. The imaging technique presented in this paper uses events where a gamma undergoes Compton scattering. The positions and energies deposited by the Compton scattered gamma define the surface of a Compton cone (CC) which is the locus of all possible positions of the point source, allowed by the Compton kinematics. The position of the same point source is also located somewhere on the LOR. Therefore, the position of the point source is defined by the 3 gammas and is given by the intersection point of the LOR and the Compton cone inside the Field of View (FOV) of the scanner. We refer to this method as CC×LOR. This new technique can locate the point source with an uncertainty of about 1 mm, after collecting a minimum of 200 CC×LOR events.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":" 28","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139393270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-01DOI: 10.1088/1748-0221/19/01/C01001
P. Galve, B. Rodriguez-Vila, J. Herraiz, V. García-Vázquez, N. Malpica, José Manuel Udías, A. Torrado-Carvajal
Hybrid imaging modalities combine two or more medical imaging techniques offering exciting new possibilities to image the structure, function and biochemistry of the human body in far greater detail than has previously been possible to improve patient diagnosis. In this context, simultaneous Positron Emission Tomography and Magnetic Resonance (PET/MR) imaging offers great complementary information, but it also poses challenges from the point of view of hardware and software compatibility. The PET signal may interfere with the MR magnetic field and vice-versa, posing several challenges and constrains in the PET instrumentation for PET/MR systems. Additionally, anatomical maps are needed to properly apply attenuation and scatter corrections to the resulting reconstructed PET images, as well motion estimates to minimize the effects of movement throughout the acquisition. In this review, we summarize the instrumentation implemented in modern PET scanners to overcome these limitations, describing the historical development of hybrid PET/MR scanners. We pay special attention to the methods used in PET to achieve attenuation, scatter and motion correction when it is combined with MR, and how both imaging modalities may be combined in PET image reconstruction algorithms.
混合成像模式结合了两种或两种以上的医学成像技术，提供了令人兴奋的新可能性，可对人体的结构、功能和生物化学进行比以往更详细的成像，从而改善对病人的诊断。在这种情况下，同步正电子发射断层扫描和磁共振成像（PET/MR）可提供大量互补信息，但从硬件和软件兼容性的角度来看，它也带来了挑战。PET 信号可能会干扰 MR 磁场，反之亦然，这给 PET/MR 系统的 PET 仪器带来了一些挑战和限制。此外，还需要解剖图对重建的 PET 图像进行适当的衰减和散射校正，以及运动估计，以尽量减少整个采集过程中的运动影响。在这篇综述中，我们总结了现代 PET 扫描仪为克服这些限制而采用的仪器，介绍了 PET/MR 混合扫描仪的历史发展。我们特别关注 PET 与 MR 结合使用时实现衰减、散射和运动校正的方法，以及如何在 PET 图像重建算法中结合这两种成像模式。
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Pub Date : 2023-12-01DOI: 10.1088/1748-0221/18/12/C12002
W. Kim, K. Ko, S. Lee, J. Park, G. Song, K. Lim, G. Cho
In high-radiation environments, measured pile-up pulses can lead to unavoidable issues such as total count loss and spectrum distortion. Additionally, the recording of large volumes of data within a short period makes real-time processing difficult. In this study, a deep learning-based pulse height estimation (PHE) method was optimized to perform pile-up signal correction in high-radiation fields. First, we adopted a previous deep-learning-based PHE method that allows for fast correction without being restricted to specific detectors. However, the peak-finding method was slightly modified to improve the count restoration rate. Moreover, the input data length of the deep learning model was optimized for convolutional neural networks (CNN) and deep neural networks (DNN) to achieve the maximum correction performance using minimal input data. A series of single pulses was experimentally obtained from a LaBr3 detector with a short decay time to prepare a dataset for training the deep learning models. The pile-up signals were generated by randomly synthesizing single pulses. Samples around their peaks were sliced using the peak-finding method and used as input data for the deep learning models. As a result of the optimization, the modified peak-finding method improved the count restoration rate compared to the previous method by effectively detecting the peaks of tail pile-up, and peak pile-up pulses. Furthermore, the input data length and region were optimized based on the performance evaluation of each deep learning model. Despite having a simpler architecture than the CNN model, the DNN model demonstrated excellent PHE performance. The results of this study showed the efficient and practical considerations necessary for applying pile-up signal correction in high-radiation fields.
{"title":"Optimizing deep learning-based piled-up pulse height correction method for high radiation-field application","authors":"W. Kim, K. Ko, S. Lee, J. Park, G. Song, K. Lim, G. Cho","doi":"10.1088/1748-0221/18/12/C12002","DOIUrl":"https://doi.org/10.1088/1748-0221/18/12/C12002","url":null,"abstract":"In high-radiation environments, measured pile-up pulses can lead to unavoidable issues such as total count loss and spectrum distortion. Additionally, the recording of large volumes of data within a short period makes real-time processing difficult. In this study, a deep learning-based pulse height estimation (PHE) method was optimized to perform pile-up signal correction in high-radiation fields. First, we adopted a previous deep-learning-based PHE method that allows for fast correction without being restricted to specific detectors. However, the peak-finding method was slightly modified to improve the count restoration rate. Moreover, the input data length of the deep learning model was optimized for convolutional neural networks (CNN) and deep neural networks (DNN) to achieve the maximum correction performance using minimal input data. A series of single pulses was experimentally obtained from a LaBr3 detector with a short decay time to prepare a dataset for training the deep learning models. The pile-up signals were generated by randomly synthesizing single pulses. Samples around their peaks were sliced using the peak-finding method and used as input data for the deep learning models. As a result of the optimization, the modified peak-finding method improved the count restoration rate compared to the previous method by effectively detecting the peaks of tail pile-up, and peak pile-up pulses. Furthermore, the input data length and region were optimized based on the performance evaluation of each deep learning model. Despite having a simpler architecture than the CNN model, the DNN model demonstrated excellent PHE performance. The results of this study showed the efficient and practical considerations necessary for applying pile-up signal correction in high-radiation fields.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":" 10","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138617987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.1088/1748-0221/18/12/T12007
Z.B. Lin, Z. Pan, Z. Wang, Z.Y. He, T.Y. Yang, Z. Chen, Y. Yuan, Z.C. Kang, F. Xie, Q. Li, J.D. Liu, B. Ye
A position-sensitive multi-compound inspection methodology using Muonic X-ray Emission Spectroscopic (μ-XES) element analysis is proposed due to the ability of the coded aperture imaging technique to maintain the relative intensity of X-rays. This methodology can simultaneously obtain the atomic ratio of different regions of the sample under study. Therefore, the mis-judgements of material compositions caused by averaging results can be reduced. The atomic ratio reconstruction quality is mainly related to X-ray counts (Nx ), atomic ratios of materials (AT ), size and placement of sample blocks. In this work, several different sample blocks made of light elements were designed by GEANT4 Monte Carlo (MC) simulations to study the influences of Nx , AT , size and placement of sample on atomic ratio reconstruction quality. In the inspection of multiple sample blocks, this methodology successfully distinguished the material compositions from different regions by reconstructing the atomic ratios of C/N and O/N. Moreover, this methodology can clearly image element blocks larger than 2 × 2 mm2.
由于编码孔径成像技术能够保持 X 射线的相对强度，因此提出了一种利用μ-XES 元素分析法进行位置敏感的多化合物检测方法。这种方法可以同时获得所研究样品不同区域的原子比率。因此，可以减少平均结果对材料成分的误判。原子比重建质量主要与 X 射线计数（Nx）、材料原子比（AT）、样品块的大小和位置有关。在这项工作中，利用 GEANT4 蒙特卡洛（MC）模拟设计了几种不同的轻元素样品块，以研究 Nx、AT、样品大小和放置位置对原子比重建质量的影响。在对多个样品块的检测中，该方法通过重建 C/N 和 O/N 的原子比，成功区分了不同区域的材料成分。此外，该方法还能对大于 2 × 2 mm2 的元素块进行清晰成像。
{"title":"Feasibility study of a coded aperture imaging technique for position-sensitive muonic X-ray atomic ratio reconstruction","authors":"Z.B. Lin, Z. Pan, Z. Wang, Z.Y. He, T.Y. Yang, Z. Chen, Y. Yuan, Z.C. Kang, F. Xie, Q. Li, J.D. Liu, B. Ye","doi":"10.1088/1748-0221/18/12/T12007","DOIUrl":"https://doi.org/10.1088/1748-0221/18/12/T12007","url":null,"abstract":"A position-sensitive multi-compound inspection methodology using Muonic X-ray Emission Spectroscopic (μ-XES) element analysis is proposed due to the ability of the coded aperture imaging technique to maintain the relative intensity of X-rays. This methodology can simultaneously obtain the atomic ratio of different regions of the sample under study. Therefore, the mis-judgements of material compositions caused by averaging results can be reduced. The atomic ratio reconstruction quality is mainly related to X-ray counts (Nx ), atomic ratios of materials (AT ), size and placement of sample blocks. In this work, several different sample blocks made of light elements were designed by GEANT4 Monte Carlo (MC) simulations to study the influences of Nx , AT , size and placement of sample on atomic ratio reconstruction quality. In the inspection of multiple sample blocks, this methodology successfully distinguished the material compositions from different regions by reconstructing the atomic ratios of C/N and O/N. Moreover, this methodology can clearly image element blocks larger than 2 × 2 mm2.","PeriodicalId":16184,"journal":{"name":"Journal of Instrumentation","volume":"99 ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139016629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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