The Muon Portal Project has built a prototype of a real size detector (6m×3m×7 m) for the inspection of containers by muon tomography. This technique may provide 2D and 3D images of the interior of a ...container, to identify the presence of high-Z materials. In the present Project, 4800 extruded scintillator strips were arranged such as to cover four X–Y detection planes (6m×3 m), two placed above and two below the container to be inspected. Silicon photomultipliers were used as photosensors, to collect the light transported by Wave Length Shifter (WLS) fibres embedded in the scintillator strips. First tomographic images are here presented.
In this paper we present the results of the first electrical and optical characterization performed on 1 mm 2 total area Silicon Photomultipliers (SiPM) fabricated in standard silicon planar ...technology at the STMicroelectronics Catania R&D clean room facility. The device consists of 289 microcells and has a geometrical fill factor of 48%. Breakdown voltage, gain, dark noise rate, crosstalk, photon detection efficiency and linearity have been measured in our laboratories. The optical characterization has been performed by varying the temperature applied to the device. The results shown in the manuscript demonstrate that the device already exhibits relevant features in terms of low dark noise rate and inter-pixel crosstalk probability, high photon detection efficiency, good linearity and single photoelectron resolution. These characteristics can be considered really promising in view of the final application of the photodetector in the Positron Emission Tomography (PET).
Cosmic ray tomography is a technique which exploits the multiple Coulomb scattering of highly penetrating cosmic ray-produced muons to perform non-destructive inspection of high-Z materials without ...the use of artificial radiation. A muon tomography detection system can be used as a portal monitor at border crossing points for detecting illegal targeted objects. The Muon Portal Project is a joint initiative between Italian research and industrial partners, aimed at the construction of a real size detector prototype (6×3×7m3) for the inspection of cargo containers by the muon scattering technique. The detector consists of four XY tracking planes, two placed above and two below the container to be inspected. After a research and development phase, which led to the choice and test of the individual components, the construction and installation of the detection modules is almost completed. In this paper the present status of the Project is reported, focusing on the design and construction phase, as well as on the preliminary results obtained with the first detection planes.
Extensive electrical model of large area silicon photomultipliers Condorelli, G.; Sanfilippo, D.; Valvo, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2011, Letnik:
654, Številka:
1
Journal Article
Recenzirano
In this paper the full electrical model of silicon photomultipliers fabricated at STMicroelectronics Catania R&D clean room facilities is presented. An accurate investigation on both SiPM single ...microcell and entire SiPM structure to extrapolate all the electrical elements has been executed by means of dedicated characterizations carried out on appropriate layout structure. The electrical simulations results are compared to the experimental data showing a good fit and therefore verifying the accuracy of the proposed model. This model can be used to describe all the SiPMs with different sizes manufactured using the same technology. Moreover, starting from this extensive electrical model, custom application software was developed in order to predict the possibility to profitably use the SiPM technology for different applications.
Experimental results from a dataset collected with a full-scale muon tomograph for the inspection of cargo containers were studied in a single scattering scenario with a multiparametric analysis ...based on the method of the Point Of Closest Approach (Poca). To search for high-Z materials, a 4
dm
3
Pb block was positioned inside the volume to be inspected, in order to quantitatively investigate the appearance of the Poca signal. Signal-to-noise ratio and significance of the Poca signal were investigated by means of mono-dimensional spectra of the Poca components, for different values of the scattering angle between the incoming and outgoing muon tracks and with different angle-dependent weights. A systematic scan of two-dimensional maps was also carried out, as a strategy to search for possible enhancements to the Poca signal. A comparison was also done between the results obtained from the two half-volumes, one containing the Pb block and one left empty, to take into account the response of the detector and some aspects of the Poca strategy.
In this paper, we present the results of the first noise characterization performed on our novel 100-channel silicon photomultiplier. We have improved our previous single-photon avalanche photodiode ...technology in order to set up a working device with outstanding features in terms of single-photon resolving power up to R = 45, timing resolution down to 100 ps, and photon-detection efficiency of 14% at 420 nm. Tests were performed, and features were measured, as a function of the bias voltage and of the incident photon flux. A dedicated data-analysis procedure was developed that allows one to extract at once the relevant parameters and quantify the noise.
In this paper, we present the results of the charge and time characterization performed on our novel 100-channel silicon photomultiplier. We have improved our previous single-photon-avalanche-diode ...technology in order to set up a working device with outstanding features in terms of single-photon resolving power up to R = 45, a timing resolution down to 100 ps, and photon-detection efficiency of 14% at 420 nm. Tests were performed, and features were measured as a function of the bias voltage and of the incident photon flux. A dedicated data analysis procedure was developed that allows to extract at once the relevant parameters from the amplitude spectra and to determine the timing features.
The results of time resolution studies with silicon photomultipliers (SiPMs) read out with high bandwidth constant fraction discrimination electronics were presented earlier 1–3. Here we describe the ...application of fast waveform digitization readout based on the DRS4 chip 4, a switched capacitor array (SCA) produced by the Paul Scherrer Institute, to further our goal of developing high time resolution detectors based on SiPMs. The influence of the SiPM signal shape on the time resolution was investigated. Different algorithms to obtain the best time resolution are described, and test beam results are presented.
The Muon Portal Project has as its goal the design and construction of a real-size working detector prototype in scale 1:1, to inspect the content of travelling containers by means of the secondary ...cosmic-ray muon radiation and to recognize high-Z hidden materials (i.e. U, Pu). The tomographic image is obtained by reconstructing the input and output trajectories of each muon when it crosses the container and, consequently, the scattering angle, making use of two trackers placed above and below the container. The scan is performed without adding any external radiation, in a reasonable time (few minutes) and with a good spatial and angular resolution. The detector consists of 8 planes each segmented in 6 identical modules. Each module is made of scintillating strips with two WaveLength Shifting fibers (WLS) inside, coupled to Silicon photomultipliers. The customized read-out electronics employs programmable boards. Thanks to a smart read-out system, the number of output channels is reduced by a factor 10. The signals from the front-end modules are sent to the read-out boards, in order to convert analog signals to digital ones, by comparison with a threshold. The data are pre-analyzed and stored into a data acquisition PC. After an intense measurement and simulation campaign to carefully characterize the detector components, the first detection modules ( 1 ×3 m 2 ) have been already built. In this paper the detector architecture, particularly focusing on the used electronics and the main preliminary results will be presented.
Preliminary results concerning the study of timing and energy resolution properties of recent Silicon Photomultipliers (SiPMs) devices by STMicroelectronics are here discussed in view of their ...possible applications in TOF PET modules and PET/MRI hybrid systems. A pair of devices with 60×60 microcells and an active area of 3.5×3.5mm2 have been coupled to 3×3×15mm3 LYSO crystals and fully characterized. Measurements of the linearity response with different gamma sources and of the timing resolution with the two 511keV photons from a 22Na positron source have been carried out.
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