Detector de partículas híbrido con resolución espacial mejorada
Loading...
Date
2024
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
En la actualidad, los detectores de partículas pueden ser encontrado en diversos instrumentos utilizados en distintos campos, desde la medicina hasta la física de partículas. Para la construcción de estos instrumentos uno de los elementos comúnmente utilizados son los centelladores plásticos orgánicos, debido a su facilidad de producción y bajo costo. Los instrumentos que se han implementado, en general, se pueden dividir en dos arquitecturas de detección: segmentados y tiempo de vuelo. La principal desventaja de ellos es que, mientras el primero utiliza un gran número de canales de lectura, presentando un mayor costo, el segundo no alcanza una resolución espacial suficiente para ciertas aplicaciones. Es por esto que se presenta un nuevo concepto híbrido de detectores de partículas que permite una resolución espacial del orden de la de los detectores segmentados, pero con un menor número de canales de lectura al utilizar información del tiempo de vuelo. Para transformar cada elemento de resolución en diferencias de tiempo se propuso una línea de retardo discreta. Se introdujo una nueva cifra de desempeño, Longitud Sensible Específica (SSL), para comparar de manera efectiva detectores que utilizan diferentes técnicas y lógicas de posicionamiento. Se desarrolló un prototipo unidimensional conformado por centelladores plásticos y fotomultiplicadores de silicio (SiPM) acoplados a ellos. Para aumentar el número de elementos de resolución se utilizó una técnica de solapamiento de centelladores. Cada SiPM se conectó a una intersección de la línea de retardo discreta, y los extremos de esta se acoplaron a dos módulos de lectura formados por un preamplificador, pulse-shaper y discriminador. Las pruebas realizadas mostraron la factibilidad de resolver la posición de los centelladores activados mediante las diferencias de tiempo de llegada de las señales eléctricas que se transmiten por la línea de retardo discreta. Los resultados indicaron que la resolución espacial del prototipo es del orden de los milímetros, similar a lo obtenido en instrumentos segmentados. Por otro lado, al utilizar sólo dos canales de lectura para determinar las diferencias de tiempo de las señales, la lógica de lectura del prototipo es comparable con la de los instrumentos basados en tiempo de vuelo. Comparando el prototipo desarrollado con diferentes instrumentos de la literatura en términos de la SSL, se observó que el valor de esta cifra es del orden de la de los instrumentos basados en tiempo de vuelo, pero con una mejor resolución espacial. Esto permite decir que el concepto propuesto utiliza de manera más eficiente los canales de lectura en comparación con otras implementaciones.
Nowadays, particle detectors can be found in a variety of instruments used in different fields, from medicine to particle physics. For the construction of these instruments, one of the most used elements are organic plastic scintillators, due to their ease of production and low cost. The instruments that have been implemented can generally be divided into two detection architectures: segmented and time-of-flight. The main disadvantages are that, while the former uses several readout channels and is more expensive, the latter does not achieve sufficient spatial resolution for certain applications. This is why a new hybrid concept of particle detectors is presented that allows a spatial resolution on the order of segmented detectors, but with a smaller number of readout channels by using a readout based on time-of-flight detectors. To transform each resolution element into time differences, a discrete delay line was proposed. A new figure of merit, Specific Sensitive Length (SSL), was introduced to effectively compare detectors using different tracking techniques and logic. This figure of merit provides information on the readout channel efficiency and particle tracking effectiveness for each instrument. A one-dimensional prototype consisting of plastic scintillators and silicon photomultiplier (SiPM) sensors coupled to them was developed. A scintillator overlapping technique was used to increase the number of resolution elements. Each SiPM was connected to an intersection of the discrete delay line, and the ends of the discrete delay line were coupled to two readout modules consisting of a preamplifier, pulse-shaper and discriminator. Tests showed the feasibility of resolving the position of the activated scintillators by means of the time-of arrival differences of the electrical signals transmitted over the discrete delay line. The results revealed that the spatial resolution of the prototype is in the order of millimetres, similar to that of segmented instruments. On the other hand, by using only two readout channels to determine the time differences of the signals, the readout logic of the prototype is comparable to that of time-of-flight based instruments. Comparing the developed prototype with different instruments in the literature in terms of SSL, it was observed that the value of this figure of merit is in the order that of time-of-flight based instruments, but with a better spatial resolution. This makes it possible to say that the proposed concept makes more efficient use of the readout channels compared to other implementations.
Nowadays, particle detectors can be found in a variety of instruments used in different fields, from medicine to particle physics. For the construction of these instruments, one of the most used elements are organic plastic scintillators, due to their ease of production and low cost. The instruments that have been implemented can generally be divided into two detection architectures: segmented and time-of-flight. The main disadvantages are that, while the former uses several readout channels and is more expensive, the latter does not achieve sufficient spatial resolution for certain applications. This is why a new hybrid concept of particle detectors is presented that allows a spatial resolution on the order of segmented detectors, but with a smaller number of readout channels by using a readout based on time-of-flight detectors. To transform each resolution element into time differences, a discrete delay line was proposed. A new figure of merit, Specific Sensitive Length (SSL), was introduced to effectively compare detectors using different tracking techniques and logic. This figure of merit provides information on the readout channel efficiency and particle tracking effectiveness for each instrument. A one-dimensional prototype consisting of plastic scintillators and silicon photomultiplier (SiPM) sensors coupled to them was developed. A scintillator overlapping technique was used to increase the number of resolution elements. Each SiPM was connected to an intersection of the discrete delay line, and the ends of the discrete delay line were coupled to two readout modules consisting of a preamplifier, pulse-shaper and discriminator. Tests showed the feasibility of resolving the position of the activated scintillators by means of the time-of arrival differences of the electrical signals transmitted over the discrete delay line. The results revealed that the spatial resolution of the prototype is in the order of millimetres, similar to that of segmented instruments. On the other hand, by using only two readout channels to determine the time differences of the signals, the readout logic of the prototype is comparable to that of time-of-flight based instruments. Comparing the developed prototype with different instruments in the literature in terms of SSL, it was observed that the value of this figure of merit is in the order that of time-of-flight based instruments, but with a better spatial resolution. This makes it possible to say that the proposed concept makes more efficient use of the readout channels compared to other implementations.
Description
Tesis (Doctor in Engineering Sciences)--Pontificia Universidad Católica de Chile, 2024