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Author |
AGATA Collaboration; Doncel, M.; Recchia, F.; Quintana, B.; Gadea, A.; Farnea, E. |
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Title |
Experimental test of the background rejection, through imaging capability, of a highly segmented AGATA germanium detector |
Type |
Journal Article |
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Year  |
2010 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
622 |
Issue |
3 |
Pages |
614-618 |
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Keywords |
Gamma spectroscopy; Gamma tracking; Imaging; Position-sensitive germanium detectors |
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Abstract |
The development of highly segmented germanium detectors as well as the algorithms to identify the position of the interaction within the crystal opens the possibility to locate the gamma-ray source using Compton imaging algorithms. While the Compton-suppression shield, coupled to the germanium detector in conventional arrays, works also as an active filter against the gamma rays originated outside the target, the new generation of position sensitive gamma-ray detector arrays has to fully rely on tracking capabilities for this purpose. In specific experimental conditions, as the ones foreseen at radioactive beam facilities, the ability to discriminate background radiation improves the sensitivity of the gamma spectrometer. In this work we present the results of a measurement performed at the Laboratori Nazionali di Legnaro (LNL) aiming the evaluation of the AGATA detector capabilities to discriminate the origin of the gamma rays on an event-by-event basis. It will be shown that, exploiting the Compton scattering formula, it is possible to track back gamma rays coming from different positions, assigning them to specific emitting locations. These imaging capabilities are quantified for a single crystal AGATA detector. |
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Address |
[Doncel, M.; Quintana, B.] Univ Salamanca, Lab Radiac Ionizantes, E-37008 Salamanca, Spain, Email: doncel@usal.es |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Language |
English |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Medium |
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Expedition |
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Conference |
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Notes |
ISI:000282562700017 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
257 |
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Author |
Linhart, V.; Burdette, D.; Chessi, E.; Cindro, V.; Clinthorne, N.H.; Cochran, E.; Grosicar, B.; Honscheid, K.; Kagan, H.; Lacasta, C.; Llosa, G.; Mikuz, M.; Stankova, V.; Studen, A.; Weilhammer, P.; Zontar, D. |
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Title |
Spectroscopy study of imaging devices based on silicon Pixel Array Detector coupled to VATAGP7 read-out chips |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
6 |
Issue |
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Pages |
C01092 - 8pp |
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Keywords |
Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA); Compton imaging |
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Abstract |
Spectroscopic and timing response studies have been conducted on a detector module consisting of a silicon Pixel Array Detector bonded on two VATAGP7 read-out chips manufactured by Gamma-Medica Ideas using laboratory gamma sources and the internal calibration facilities (the calibration system of the read-out chips). The performed tests have proven that the chips have (i) non-linear calibration curves which can be approximated by power functions, (ii) capability to measure the energy of photons with energy resolution better than 2 keV (exact range and resolution depend on experimental setup), (iii) the internal calibration facility which provides 6 out of 16 available internal calibration charges within our region of interest (spanning the Compton edge of 511 keV photons). The peaks induced by the internal calibration facility are suitable for a fit of the calibration curves. However, they are not suitable for measurements of equivalent noise charge because their full width at half maximum varies with their amplitude. These facts indicate that the VATAGP7 chips are useful and precise tools for a wide variety of spectroscopic devices. We have also explored time walk of the module and peaking time of the spectroscopy signals provided by the chips. We have observed that (iv) the time walk is caused partly by the peaking time of the signals provided by the fast shaper of the chips and partly by the timing uncertainty related to the varying position of the photon interaction, (v) the peaking time of the spectroscopy signals provided by the chips increases with increasing pulse height. |
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Address |
[Linhart, V.; Lacasta, C.; Llosa, G.; Stankova, V.] UVEG, CSIC, IFIC, Expt Phys Dept,Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: Vladimir.Linhart@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000291345600097 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
645 |
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Author |
Rodriguez-Alvarez, M.J.; Sanchez, F.; Soriano, A.; Iborra, A.; Mora, C. |
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Title |
Exploiting symmetries for weight matrix design in CT imaging |
Type |
Journal Article |
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Year |
2011 |
Publication |
Mathematical and Computer Modelling |
Abbreviated Journal |
Math. Comput. Model. |
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Volume |
54 |
Issue |
7-8 |
Pages |
1655-1664 |
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Keywords |
Computerized tomography imaging; Polar grid; System matrix; Rotation symmetries; ART |
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Abstract |
In this paper we propose several methods of constructing the system matrix (SM) of a Computed Tomography (CT) scanner with two objectives: (1) to construct SMs in the shortest possible time and store them in an ordinary PC without losing quality, (2) to analyze the possible applications of the proposed method to 3D, taking into account SMs' sizes, computing time and reconstructed image quality. In order to build the SM, we propose two new field of view (FOV) pixellation schemes, based on a polar coordinate system (polar grid) by taking advantage of the polar rotation symmetries of CT devices. Comparisons between the SMs proposed are performed using two phantom and a real CT-simulator images. Global error, contrast, noise and homogeneity of the reconstructed images are discussed. |
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Address |
[Rodriguez-Alvarez, MJ; Iborra, A; Mora, C] Univ Politecn Valencia, Inst Matemat Multidisciplinar, Valencia 46022, Spain, Email: mjrodri@imm.upv.es |
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Corporate Author |
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Thesis |
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Publisher |
Pergamon-Elsevier Science Ltd |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0895-7177 |
ISBN |
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Medium |
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Expedition |
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Conference |
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Notes |
WOS:000293269200007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
708 |
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Author |
Carles, M.; Lerche, C.W.; Sanchez, F.; Mora, F.; Benlloch, J.M. |
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Title |
Position correction with depth of interaction information for a small animal PET system |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
648 |
Issue |
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Pages |
S176-S180 |
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Keywords |
DOI; PET; Positioning algorithm; Gamma ray imaging; Continuous scintillators |
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Abstract |
In this work we study the effects on the spatial resolution when depth of interaction (001) information is included in the parameterization of the line of response (LOR) for a small animal positron emission tomography (PET) system. One of the most important degrading factors for PET is the parallax error introduced in systems that do not provide DOI information of the recorded gamma-rays. Our group has designed a simple and inexpensive method for DOI determination in continuous scintillation crystals. This method is based, on one hand, in the correlation between the scintillation light distribution width in monolithic crystals and the DOI, and, on the other hand, on a small modification of the widely applied charge dividing circuits (CDR). In this work we present a new system calibration that includes the DOI information, and also the development of the correction equations that relates the LOR without and with DOI information. We report the results obtained for different measurements along the transaxial field of view (FOV) and the image quality enhancement achieved specially at the edge of the FOV. |
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Address |
[Carles, M.; Sanchez, F.; Benlloch, J. M.] Inst Fis Corpuscular CSIC UV, Valencia 46071, Spain, Email: montcar@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000305376900046 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
1067 |
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Author |
Llosa, G.; Barrio, J.; Lacasta, C.; Callier, S.; Raux, L.; de La Taille, C. |
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Title |
First tests in the application of silicon photomultiplier arrays to dose monitoring in hadron therapy |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
648 |
Issue |
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Pages |
S96-S99 |
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Keywords |
Hadron therapy; Compton imaging; LaBr3; Continuous crystal; SiPM; MPPC; G-APD |
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Abstract |
A detector head composed of a continuous LaBr3 crystal coupled to a silicon photomultiplier array has been mounted and tested, for its use in a Compton telescope for dose monitoring in hadron therapy. The LaBr3 crystal has 16 mm x 18 mm x 5 mm size, and it is surrounded with reflecting material in five faces. The SiPM array has 16 (4 x 4) elements of 3 mm x 3 mm size. The SPIROC1 ASIC has been employed as readout electronics. The detector shows a linear behavior up to 1275 keV. The energy resolution obtained at 511 keV is 7% FWHM, and it varies as one over the square root of the energy up to the energies tested. The variations among the detector channels are within 12%. A preliminary measurement of the timing resolution gives 7 ns FWHM. The spatial resolution obtained with the center of gravity method is 1.2 mm FWHM. The tests performed confirm the correct functioning of the detector. |
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Address |
[Llosa, G.; Barrio, J.; Lacasta, C.] Inst Fis Corpuscular IFIC CSIC UVEG, Valencia, Spain, Email: gabriela.llosa@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000305376900026 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1068 |
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| Permanent link to this record |
