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Author  |
Muñoz, E.; Barrientos, L.; Bernabeu, J.; Borja-Lloret, M.; Llosa, G.; Ros, A.; Roser, J.; Oliver, J.F. |
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Title |
A spectral reconstruction algorithm for two-plane Compton cameras |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
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Volume |
65 |
Issue |
2 |
Pages |
025011 - 17pp |
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Keywords |
Compton imaging; Compton camera; hadron therapy; image reconstruction |
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Abstract |
One factor limiting the current applicability extent of hadron therapy is the lack of a reliable method for real time treatment monitoring. The use of Compton imaging systems as monitors requires the correct reconstruction of the distribution of prompt gamma productions during patient irradiation. In order to extract the maximum information from all the measurable events, we implemented a spectral reconstruction method that assigns to all events a probability of being either partial or total energy depositions. The method, implemented in a list-mode maximum likelihood expectation maximization algorithm, generates a four dimensional image in the joint spatial-spectral domain, in which the voxels containing the emission positions and energies are obtained. The analytical model used for the system response function is also employed to derive an analytical expression for the sensitivity, which is calculated via Monte Carlo integration. The performance of the method is evaluated through reconstruction of various experimental and simulated sources with different spatial and energy distributions. The results show that the proposed method can recover the spectral and spatial information simultaneously, but only under the assumption of ideal measurements. The analysis of the Monte Carlo simulations has led to the identification of two important degradation sources: the mispositioning of the gamma interaction point and the missing energy recorded in the interaction. Both factors are related to the high energy transferred to the recoil electrons, which can travel far from the interaction point and even escape the detector. These effects prevent the direct application of the current method in more realistic scenarios. Nevertheless, experimental point-like sources have been accurately reconstructed and the spatial distributions and spectral emission of complex simulated phantoms can be identified. |
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Address |
[Munoz, Enrique; Barrientos, Luis; Bernabeu, Jose; Borja-Lloret, Marina; Llosa, Gabriela; Ros, Ana; Roser, Jorge; Oliver, Josep F.] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain, Email: Enrique.Munoz@ific.uv.es |
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Publisher |
Iop Publishing Ltd |
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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 |
0031-9155 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000520111400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
4332 |
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Author |
Muñoz, E.; Barrio, J.; Bemmerer, D.; Etxebeste, A.; Fiedler, F.; Hueso-Gonzalez, F.; Lacasta, C.; Oliver, J.F.; Romer, K.; Solaz, C.; Wagner, L.; Llosa, G. |
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Title |
Tests of MACACO Compton telescope with 4.44 MeV gamma rays |
Type |
Journal Article |
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Year |
2018 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
13 |
Issue |
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Pages |
P05007 - 13pp |
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Keywords |
Compton imaging; Instrumentation for hadron therapy; Gamma detectors (scintillators, CZT, HPG, HgI etc); Photon detectors for UV, visible and IR photons (solid state) (PIN diodes, APDs, Si PMTs, G APDs, CCDs, EBCCDs, EMCCDs etc) |
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Abstract |
Hadron therapy offers the possibility of delivering a large amount of radiation dose to tumors with minimal absorption by the surrounding healthy tissue. In order to fully exploit the advantages of this technique, the use of real-time beam monitoring devices becomes mandatory. Compton imaging devices can be employed to map the distribution of prompt gamma emission during the treatment and thus assess its correct delivery. The Compton telescope prototype developed at IFIC-Valencia for this purpose is made of three layers of LaBr3 crystals coupled to silicon photomultipliers. The system has been tested in a 4.44 MeV gamma field at the 3 MV Tandetron accelerator at HZDR, Dresden. Images of the target with the system in three different positions separated by 10 mm were successfully reconstructed. This indicates the ability of MACACO for imaging the prompt gamma rays emitted at such energies. |
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Address |
[Munoz, E.; Barrio, J.; Etxebeste, A.; Lacasta, C.; Oliver, J. F.; Solaz, C.; Llosa, G.] Univ Valencia, CSIC, Inst Fis Corpuscular, Parque Cient,C Catedrat Jose Beltran 2, E-46980 Paterna, Valencia, Spain, Email: Enrique.Munoz@ific.uv.es |
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Corporate Author |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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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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Expedition |
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Conference |
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Notes |
WOS:000431716900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3575 |
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Author |
Muñoz, E.; Barrio, J.; Bernabeu, J.; Etxebeste, A.; Lacasta, C.; Llosa, G.; Ros, A.; Roser, J.; Oliver, J.F. |
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Title |
Study and comparison of different sensitivity models for a two-plane Compton camera |
Type |
Journal Article |
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Year |
2018 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
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Volume |
63 |
Issue |
13 |
Pages |
135004 - 19pp |
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Keywords |
Compton camera imaging; MLEM; Monte Carlo simulations; image quality |
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Abstract |
Given the strong variations in the sensitivity of Compton cameras for the detection of events originating from different points in the field of view (FoV), sensitivity correction is often necessary in Compton image reconstruction. Several approaches for the calculation of the sensitivity matrix have been proposed in the literature. While most of these models are easily implemented and can be useful in many cases, they usually assume high angular coverage over the scattered photon, which is not the case for our prototype. In this work, we have derived an analytical model that allows us to calculate a detailed sensitivity matrix, which has been compared to other sensitivity models in the literature. Specifically, the proposed model describes the probability of measuring a useful event in a two-plane Compton camera, including the most relevant physical processes involved. The model has been used to obtain an expression for the system and sensitivity matrices for iterative image reconstruction. These matrices have been validated taking Monte Carlo simulations as a reference. In order to study the impact of the sensitivity, images reconstructed with our sensitivity model and with other models have been compared. Images have been reconstructed from several simulated sources, including point-like sources and extended distributions of activity, and also from experimental data measured with Na-22 sources. Results show that our sensitivity model is the best suited for our prototype. Although other models in the literature perform successfully in many scenarios, they are not applicable in all the geometrical configurations of interest for our system. In general, our model allows to effectively recover the intensity of point-like sources at different positions in the FoV and to reconstruct regions of homogeneous activity with minimal variance. Moreover, it can be employed for all Compton camera configurations, including those with low angular coverage over the scatterer. |
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Address |
[Munoz, Enrique; Barrio, John; Bernabeu, Jose; Etxebeste, Ane; Lacasta, Carlos; Llosa, Gabriela; Ros, Ana; Roser, Jorge; Oliver, Josep F.] Univ Valencia, CSIC, Inst Fis Corpuscular, IFIC, Valencia, Spain, Email: Enrique.Munoz@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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 |
0031-9155 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000436390800004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
3639 |
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| Permanent link to this record |
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Author |
Muñoz, E.; Barrio, J.; Etxebeste, A.; Ortega, P.G.; Lacasta, C.; Oliver, J.F.; Solaz, C.; Llosa, G. |
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Title |
Performance evaluation of MACACO: a multilayer Compton camera |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
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Volume |
62 |
Issue |
18 |
Pages |
7321-7341 |
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Keywords |
Compton imaging; Compton camera; continuous LaBr3 crystal; silicon photomultiplier; hadron therapy |
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Abstract |
Compton imaging devices have been proposed and studied for a wide range of applications. We have developed a Compton camera prototype which can be operated with two or three detector layers based on monolithic lanthanum bromide (LaBr3) crystals coupled to silicon photomultipliers (SiPMs), to be used for proton range verification in hadron therapy. In this work, we present the results obtained with our prototype in laboratory tests with radioactive sources and in simulation studies. Images of a Na-22 and an Y-88 radioactive sources have been successfully reconstructed. The full width half maximum of the reconstructed images is below 4 mm for a Na-22 source at a distance of 5 cm. |
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Address |
[Munoz, Enrique; Barrio, John; Etxebeste, Ane; Ortega, Pablo G.; Lacasta, Carlos; Oliver, Josep F.; Solaz, Carles; Llosa, Gabriela] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain, Email: Enrique.Munoz@ific.uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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 |
0031-9155 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000408229900003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3253 |
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Author |
NEXT Collaboration (Alvarez, V. et al); Ball, M.; Carcel, S.; Cervera-Villanueva, A.; Diaz, J.; Ferrario, P.; Gil, A.; Gomez-Cadenas, J.J.; Laing, A.; Liubarsky, I.; Lorca, D.; Martin-Albo, J.; Martinez, A.; Monrabal, F.; Muñoz Vidal, J.; Nebot-Guinot, M.; Rodriguez, J.; Serra, L.; Simon, A.; Sorel, M.; Yahlali, N. |
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Title |
Design and characterization of the SiPM tracking system of NEXT-DEMO, a demonstrator prototype of the NEXT-100 experiment |
Type |
Journal Article |
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Year |
2013 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
8 |
Issue |
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Pages |
T05002 - 18pp |
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Keywords |
Time projection Chambers (TPC); Gaseous imaging and tracking detectors; Photon detectors for UV; visible and IR photons (solid-state); Particle tracking detectors (Solid-state detectors) |
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Abstract |
NEXT-100 experiment aims at searching the neutrinoless double-beta decay of the Xe-136 isotope using a TPC filled with a 100 kg of high-pressure gaseous xenon, with 90% isotopic enrichment. The experiment will take place at the Laboratorio Subterraneo de Canfranc (LSC), Spain. NEXT-100 uses electroluminescence (EL) technology for energy measurement with a resolution better than 1% FWHM. The gaseous xenon in the TPC additionally allows the tracks of the two beta particles to be recorded, which are expected to have a length of up to 30 cm at 10 bar pressure. The ability to record the topological signature of the beta beta 0 nu events provides a powerful background rejection factor for the beta beta experiment. In this paper, we present a novel 3D imaging concept using SiPMs coated with tetraphenyl butadiene (TPB) for the EL read out and its first implementation in NEXT-DEMO, a large-scale prototype of the NEXT-100 experiment. The design and the first characterization measurements of the NEXT-DEMO SiPM tracking system are presented. The SiPM response uniformity over the tracking plane drawn from its gain map is shown to be better than 4%. An automated active control system for the stabilization of the SiPMs gain was developed, based on the voltage supply compensation of the gain drifts. The gain is shown to be stabilized within 0.2% relative variation around its nominal value, provided by Hamamatsu, in a temperature range of 10 degrees C. The noise level from the electronics and the SiPM dark noise is shown to lay typically below the level of 10 photoelectrons (pe) in the ADC. Hence, a detection threshold at 10 pe is set for the acquisition of the tracking signals. The ADC full dynamic range (4096 channels) is shown to be adequate for signal levels of up to 200 pe/mu s, which enables recording most of the tracking signals. |
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Address |
[Alvarez, V.; Ball, M.; Carcel, S.; Cervera, A.; Diaz, J.; Ferrario, P.; Gil, A.; Gomez-Cadenas, J. J.; Laing, A.; Liubarsky, I.; Lorca, D.; Martin-Albo, J.; Martinez, A.; Monrabal, F.; Munoz Vidal, J.; Nebot-Guinot, M.; Rodriguez, J.; Serra, L.; Simon, A.; Sorel, M.; Yahlali, N.] CSIC, Inst Fis Corpuscular IFIC, Valencia 46980, Spain, Email: gomez@mail.cern.ch; |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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 |
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 |
WOS:000320726000037 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1514 |
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| Permanent link to this record |
