Properties of the Ukraine polystyrene-based plastic scintillator UPS 923A Artikov, A.; Budagov, J.; Chirikov-Zorin, I. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2005, Letnik:
555, Številka:
1
Journal Article
Recenzirano
The polystyrene-based scintillator UPS 923A was chosen for upgrading of the muon system for the CDF detector at the Fermilab Tevatron. Properties of this scintillator such as light output, light ...attenuation, long-term stability and also timing characteristics of scintillators and wavelength-shifting fibers were investigated. The method for the Bulk Attenuation Length measurements of the scintillator to its own light emitted was proposed.
Comparison measurements of the characteristics of the UPS 923A and the polyvinyltoluene-based scintillator NE 114 are done. It was found that natural aging of the NE 114 was two times faster than that of the UPS 923A.
Monte Carlo simulations are increasingly used in scintigraphic imaging to model imaging systems and to develop and assess tomographic reconstruction algorithms and correction methods for improved ...image quantitation. GATE (GEANT4 application for tomographic emission) is a new Monte Carlo simulation platform based on GEANT4 dedicated to nuclear imaging applications. This paper describes the GATE simulation of a prototype of scintillation camera dedicated to small-animal imaging and consisting of a CsI(Tl) crystal array coupled to a position-sensitive photomultiplier tube. The relevance of GATE to model the camera prototype was assessed by comparing simulated 99mTc point spread functions, energy spectra, sensitivities, scatter fractions and image of a capillary phantom with the corresponding experimental measurements. Results showed an excellent agreement between simulated and experimental data: experimental spatial resolutions were predicted with an error less than 100 microns. The difference between experimental and simulated system sensitivities for different source-to-collimator distances was within 2%. Simulated and experimental scatter fractions in a 98-182 keV energy window differed by less than 2% for sources located in water. Simulated and experimental energy spectra agreed very well between 40 and 180 keV. These results demonstrate the ability and flexibility of GATE for simulating original detector designs. The main weakness of GATE concerns the long computation time it requires: this issue is currently under investigation by the GEANT4 and the GATE collaborations.
Online monitoring of the stopping distribution of particle beams used for radiotherapy provides the possibility of detecting possible errors in dose deposition early during a given treatment session, ...and may therefore help to improve the quality of the therapy. Antiproton annihilation events produce several long-range secondary particles which can be detected in real time by standard high energy particle physics detector systems. In this note, Monte Carlo calculations are performed in order to study the feasibility of real-time imaging by detecting charged pions produced during antiproton irradiation of typical biological targets. A simple treatment plan in a water phantom is simulated and the results show that by detecting pi+/- the position and the size of the planned target volume can be located with precision in the order of 1 mm.
The results of studies conducted with a small field of view tomographic gamma camera based on a Position Sensitive Photomultiplier Tube are reported. The system has been used for the evaluation of ...radiopharmaceuticals in small animals. Phantom studies have shown a spatial resolution of 2
mm in planar and 2–3
mm in tomographic imaging. Imaging studies in mice have been carried out both in 2D and 3D. Conventional radiopharmaceuticals have been used and the results have been compared with images from a clinically used system.
This paper investigates the possibility of developing a SPECT system that combines the high spatial resolution of position sensitive photomultiplier tubes (PSPMTs) with the excellent performance of ...iterative reconstruction algorithms. A small field of view (FOV) camera based on a PSPMT and a pixelized scintillation crystal made of CsI(Tl) have been used for the acquisition of the projections. With the use of maximum likelihood expectation maximization (ML-EM) and ordered subsets expectation maximization (OSEM) slices of the object are obtained while three-dimensional (3D) reconstruction of the object is carried out using a modified marching cubes (MMC) algorithm. The spatial resolution of tomographic images obtained with the system was 2–3
mm. The spatial resolution of a conventional system that uses filtered backprojection (FBP) for slices reconstruction was more than 9
mm.
Design and construction of new central and forward muon counters for CDF II Artikov, A.; Budagov, J.; Chirikov-Zorin, I. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2005, Letnik:
538, Številka:
1
Journal Article
Recenzirano
Odprti dostop
New scintillation counters have been designed and constructed for the upgradation of the CDF detector at the Fermilab Tevatron in order to complete the muon coverage of the central detector and to ...extend it to a larger pseudorapidity interval. A novel light collection technique using wavelength shifting fibers, together with high-quality polystyrene-based scintillator resulted in compact counters with good and stable light collection efficiency over lengths extending up to 320
cm. Their design and construction is described and results of their initial performance are reported.
Small field of view detectors based on Position Sensitive Photomultiplier Tubes (PSPMTs) have been widely used by many research groups in small-animal imaging and recently clinically in ...scintimammography. In most cases the PSPMT is coupled to pixelized scintillators since it has been shown that their use improves spatial resolution. The use of a single energy window for each crystal element is the only proposed method for scatter correction in pixelized scintillators. In this work we have modified the dual energy window subtraction technique in order to be applicable to a pixelized scintillator detector and we have evaluated its performance with real data. Hot, cold and breast phantoms have been imaged in planar mode.
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