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The setup of PET scanners usually requires an external positron source. A correct setup procedure has to ensure that the detectors are calibrated for gain adjustments, photopeak locations, and positioning maps for individual detector crystals. In order to verify the quality of the setup on a daily basis, daily quality checks are performed where the variations are checked with an external source and...
We developed a signal-known-exactly version of the ideal observer that processes data in list-mode format to perform binary classification, a useful task for arms-control treaty applications. This observer offers the best possible performance and future observer models developed in our work will be compared to this model. The two examined sources were plutonium inspection objects developed by Idaho...
Silicon Photomultipliers are the photosensor of choice for many future high energy particle detectors, among which the hadronic calorimeters designed for Particle Flow application [1]. The Hamburg group has elaborated a novel design for the single channel of a highly granular analog hadronic calorimeter, proposed by F. Simon and C. Soldner in [2], based on the direct coupling of SiPMs with a plastic...
Nonlinearity in the output signals for the energy deposited by gamma-ray interactions can seriously degrade the energy resolution of a pixellated detector when the signals from more than one pixel are summed to get the total deposited energy. Such nonlinearity can be calibrated on a pixel-by-pixel basis by using multiple gamma-ray check sources of various known energy photopeaks for gamma-ray energy...
Digitizing scintillation pulses with the Multi-voltage threshold (MVT) method shows great potentials for building all-digital positron emission tomography (PET). In this paper, we introduce the MVT method into gamma-ray spectroscopy. An accurate scintillation pulse model used in pulse fitting is especially important to get precise energy when implementing the MVT in gamma-ray spectroscopy, since a...
Certain scintillating materials are sensitive to both gamma and neutron radiation and can give information about the type of interacting radiation due to differences in the light output response. By collecting the light pulses and converting them to electrical signals the nature of the radiation can be determined by measuring the amount of electrical charge in the pulse tail - for neutrons, the pulses...
We aim at developing practical ways to measure the parameters necessary for data corrections and calibration of a PET scanner with variable geometry (ClearPEM), in order to achieve accurate quantitative images for a large range of imaging tasks using few phantom measurements. We used a decaying cylindrical phantom to determine calibration and dead time factors for a set of acquisition geometries that...
The paper presents the specific testability features included in the design of a single photon counting hybrid pixel detector readout circuit built in the 40nm CMOS. The readout integrated circuit consists of a 18×24 pixel matrix with a pitch of 100 µm. Each pixel comprises of a charge sensitive amplifier, two shapers, two discriminators, eight comparators, tens of inter-pixel connections and a digital...
This paper reports on the geometric calibration procedure of a bench-top, high-speed, and continuous-rotation preclinical computed tomography (CT) scanner that has been developed at our institution. A full 13-parameter model of the image formation process is described. Once calibrated, the model is used to modify projection data sets — the standardization operation — so that they appear to come from...
The developing of photon counting detectors makes it is feasible to obtain multi energy information from one X-ray source. Based on the photon counting system, this paper proposes a simulation of multi energy BMD method, which can lead to the promotion of current BMD accuracy as well as providing multi information of human tissue. In our simulation, we generalize the conic surface equation fitting...
The Run II of the Large Hadron Collider will confront us with new challenges, mainly due to the higher number of interactions per bunch crossing and the reduced time distance between bunches. In order to be ready for the beginning of the run, in view of an early discovery, the CMS collaboration is currently evolving the infrastructure established during Run I to monitor the data quality, to validate...
The objective of this study was to develop a maximum likelihood gamma positioning method (MLGPM) with accurate calibration of the mean detector response function (MDRF) and the statistics of output from PMTs and the next stage data acquisition electronics in a clinical SPECT detector.
New horizons in x-ray radiography and computed tomography (CT) have been opened up with the emergence of energy resolved x-ray imaging. This includes the ability to differentiate material components and estimate their equivalent thickness or relative ratio by processing a single shot acquisition image. However, such techniques require highly accurate images, especially for materials close in terms...
A precise knowledge of the geometry is always pivotal to a x-ray imaging system, such as computed tomography, digital x-ray tomosynthesis and computed laminography. A typical tomosynthesis system is referred to as the relative positions between the focal spots of the x-ray source and the detector, the object remains in a fixed position above the detector and the x-ray tube emits x-ray beams in the...
For continuous crystal based PET detectors, not only the two-dimensional (2D) plane coordinates of the interaction point, but also the depth-of-interaction (DOI) of γ events could be precisely estimated by the single-end readout of the scintillation light. In this paper, we propose a novel, practical method for DOI determination for continuous crystal PET detectors. The novelties of the method include:...
A new calibration technique for a concurrent dual band six port receiver (SPR) is presented. This calibration technique uses a modified memory polynomial (MP) to model the non-idealities and imperfections in the six port receiver architecture which includes the six port wave correlator and the diode detectors used. Using an inverse model, the in-phase and quadrature component of a transmitted signal...
Six-Port interferometers for distance measurement show a low cost solution able to operate in harsh environment where other solutions are not suitable. The increase of the distance range requires new calibration strategies in order to compensate the signals' high dynamic power range. Here, an enhanced Six-Port receiver is presented having the capability of sensing the frequency of the reference signal...
Polarimetric-hyperspectral imaging brings two traditionally independent modalities together to potentially enhance scene characterization capabilities. This could increase confidence in target detection, material identification, and background characterization over traditional hyperspectral imaging. In order to fully exploit the spectro-polarimetric signal, a careful calibration process is required...
PTB, the National Metrology Institute of Germany, and Sensor- and Lasertechnik, a company based in Germany, developed together novel THz detectors. They are based on a coated thin film pyroelectric foil. Intensive care has been taken to their sensitivity and spectral response to make them suitable for absolute power measurement of time-domain spectroscopy systems (TDS). Their power responsivity is...
An on-chip RF power sensor based on the bolometer principle is presented in this work. The sensor can be used for transmitter calibration purposes without using any RF equipment offering time and cost savings. Investigations on various layers of the fT=170GHz SiGe bipolar technology, which is used in this work, are performed and evaluated. Especially silicided polysilicon layers show a promising behavior...
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