Timing Electronics and Fast Timing Methods with Scintillation Detectors

Paulus, Thomas J.

doi:10.1109/tns.1985.4337024

Cited by 68 publications

(35 citation statements)

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“…The start signal that opens the time windows for all detectors is the signal from the electron, registered in the electron detector (13). For an event to be considered as a radiative neutron decay event there have to be simultaneous signals from the electron detector (13) and one of the gamma detectors (11), followed by a delayed signal from the proton detector (3).…”

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confidence: 99%

Comparison of two experiments on radiative neutron decay

et al. 2009

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Over 10 years ago we proposed an experiment on measuring the characteristics of radiative neutron decay in papers [1,2]. At the same time we had published the theoretical spectrum of radiative gamma quanta, calculated within the framework of the electroweak interactions, on the basis of which we proposed the methodology for the future experiment [3,4]. However, because we were denied beam time on the intensive cold neutron beam at ILL (Grenoble, France) for a number of years, we could only conduct the experiment in 2005 on the newly opened FRMII reactor of Technical University of Muenchen. The main result of this experiment was the discovery of radiative neutron decay and the measurement of its relative intensity B.R.= (3.2±1.6)·10-3 with C.L.=99.7% for radiative gamma quanta with energy over 35 kev [5,6]. Over a year after our first announcement about the results of the conducted experiment, "Nature" [7] published a letter asserting that its authors have also measured the branching ratio of radiative neutron decay B.R.= (3.13±0.34)·10-3 with C.L.=68% and gamma quanta energy from 15 to 340 kev. This article aims to compare these two experiments. It is shown that the use of strong magnetic fields in the NIST (Washington, USA) experiment methodology not only prevents any exact measurement of the branching ratio and identification of radiative neutron decay events, but also makes registration of ordinary neutron decay events impossible. PACS numbers: 13.30. Ce; 13.40.Hq; 14.20.Dh Among the many branches of elementary decay with charged particles in the final state, the radiative branch, where the decay occurs with the creation of an additional particle -the gamma quantum, is usually the most intensive, as the relative intensity ( or branching ratio B.R. ) of this mode is determined by the fine structure constant α of 10 -2 order of magnitude. This decay branch is well established and was investigated for almost all elementary particles. However, the radiative decay of the free neutronwas not discovered, and all the experiments were aimed at the study of the ordinary neutron decay branch. We conducted the first experiment on the discovery of this rare neutron decay branch in 2002 on the intensive cold neutron beams at ILL (Grenoble, France), where we received a limit for the relative intensity of this rare decay branch: B.R. < 6.9*10 -3 ( 90% C.L.) [8]. This value exceeds the theoretical value we calculated and published only in by a few times. This fact, in turn, means that in our experiment of 2002 we came very close to discovering the radiative mode of neutron decay. For reasons outside of our control we did not receive beam time on intensive cold neutron beam at ILL for a number of years and were able to continue our experiment only in 2005, after we received beam time at the newly opened FRMII 1

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Comparison of two experiments on radiative neutron decay

et al. 2009

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“…Estas fuentes de error han sido estudiadas en distintos trabajos [8,7,104,105,103,106]. Todos estos trabajos consideran métodos de extracción de tiempos puramente analógicos, poco se ha escrito sobre los efectos de la digitalización de las señales.…”

Section: Fuentes De Error Para La Determinación Del Tiempo Por La Eleunclassified

Estudio e implementación de algoritmos digitales para la mejora de la resolución temporal en sistemas de tomografía por emisión de positrones

Ferrer¹,

María²

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Estudio e implementación de algoritmos digitales para la mejora de la resolución temporal en sistemas de tomografía por emisión de positrones.Presentada por: D. José María Monzó Ferrer Para BeaMizu ni kage aru tabibito dearu "En el agua hay un reflejo Es alguien que va de viaje " Taneda SantôkaTsukareta ashi e tonbô tomatta "En mis piernas cansadas se ha posado una libélula" Taneda Santôka Akikaze no ishi o hirou "Con viento de otoño recojo una piedra" Taneda Santôka AgradecimientosQuiero dedicar este trabajo a toda la gente que con todo su apoyo lo ha hecho posible.Gracias a mis directores Christoph Lerche y Raúl Esteve por toda su dedicación y todos sus consejos. Ellos han hecho más fácil llevar a cabo esta aventura.También quiero agradecer a Vicente Herrero por todo su conocimiento y ayuda desinteresada durante estos largos años. A Rafa Gadea yÁngel Sebastiá por creer en mí y darme la oportunidad de iniciar este viaje. A Jorge Martínez por todo el apoyo que me dio en los inicios de este camino. A Ricardo, Ximo,Ángel, Curro, Paco Mora y la gente de teleco siempre dispuesta a ayudarte en todo momento.Me gustaría expresar mi agradecimiento a la gente del laboratorio y del instituto entre los cuales muchos hace tiempo que trascendieron la barrera del compañerismo alcanzando la amistad, Nestor, Vicente, Ana, Ramón, Christoph y Montse. Con ellos he vivido muy buenos momentos, y son uno de los ingredientes más importantes que hacen que el trabajo de investigador sea tan gratificante.Quiero agradecer por toda su amistad a Quique, Marga, Pablo S., Pablo C., Víctor, Ana, Pablo V. y otros muchos que siempre estuvieron junto a mí. viiiEste trabajo también ha sido posible gracias a mi familia, en especial mi abuelo que desde pequeño me inculcó la fascinación por el conocimiento y la ciencia. A mis padres y mis hermanos: Jose María, Maria José, César y David. Soy lo que soy gracias a ellos, y gracias a ellos seré lo que seré.Porúltimo, es importante remarcar que este trabajo pertenece a Bea, que con todo su amor y con toda su entrega consigue llenar de intensidad y emoción este y todos los proyectos que tenemos juntos. Esto tiene sentido gracias a ti.Como diría Vinicius de Moraes en la "Samba de Bençao", ¡Saravá! ResumenLa Tomografía por emisión de positrones (PET, "Positron Emission Tomography") es una técnica de diagnóstico médico que se encarga de mostrar imágenes de la distribución de radioisótopos dentro del cuerpo, permitiendo de esta forma observar procesos metabólicos que ocurren en su interior.Los sistemas PET se encargan de detectar pares de rayos gamma de 511KeV cada uno generados tras la aniquilación de un positrón con un electrón. De cada rayo gamma detectado, se obtiene su energía, la posición en la que el rayo es detectado y el tiempo exacto en el que el evento ha sido detectado. Se denomina tiempo de coincidencia a la diferencia de tiempos entre dos eventos. La resolución temporal de un sistema vendrá determinada por el error temporal cometido en la medida del tiempo de coincidencia. Una mejora en la resol...

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“…Time pick-off methods contribute their own term σ t el to time resolution; their uncertainty can be typically divided into two components depending on their source: time jitter corresponds to variations in time marks assigned to detector pulses with similar characteristics due to electronic noise, and time walk includes effects derived from variations in the signal parameters such as amplitude, rise time or shape [272].…”

Section: Analog Timing Electronicsmentioning

confidence: 99%

“…with a reference pulse waveform v 0 (t) and additive noise n (t) with variance σ 2 v , then time jitter can be estimated as [272] …”

Section: Analog Timing Electronicsmentioning

confidence: 99%

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Development of a data acquisition architecture with distributed synchronization for a Positron Emission Tomography system with integrated front-end.

Varea¹,

Ramón²

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Positron Emission Tomography (PET) is a non-invasive nuclear medical imaging modality that makes it possible to observe the distribution of metabolic substances within a patient's body after marking them with radioactive isotopes and arranging an annular scanner around him in order to detect their decays. The main applications of this technique are the detection and tracing of tumors in cancer patients and metabolic studies with small animals.The Electronic Design for Nuclear Applications (EDNA) research group within the Instituto de Instrumentación para Imagen Molecular (I3M) has been involved in the study of high performance PET systems and maintains a small experimental setup with two detector modules. This thesis is framed within the necessity of developing a new data acquisition system (DAQ) for the aforementioned setup that corrects the drawbacks of the existing one. The main objective is to define a DAQ architecture that is completely scalable, modular, and guarantees the mobility and the possibility of reusing its components, so that it admits any extension of modification of the setup and it is possible to export it directly to the configurations used by other groups or experiments. At the same time, this architecture should be compatible with the best possible resolutions attainable at the present instead of imposing artificial limits on system performance. In particular, the new DAQ system should outperform the previous one.As a first step, a general study of DAQ architectures is carried out in the context of experimental setups for PET and other high energy physics applications. On one hand, the conclusion is reached that the desired specifications require early digitization of detector signals, exclusively digital communication between modules, and the absence of a centralized trigger. On the other hand, the necessity of a very precise distributed synchronization scheme between modules becomes apparent, with errors in the order of 100 ps, and operating directly over the data links. A study of the existing methods reveals their severe limitations in terms of achievable precision. A theoretical analysis of the situation is carried out with the goal of overcoming them, and a new synchronization algorithm is proposed that is able to reach the desired resolution while getting rid of the restrictions on clock iii alignment that are imposed by virtually all usual schemes. Since the measurement of clock phase difference plays a crucial role in the proposed algorithm, extensions to the existing methods are defined and analyzed that improve them significantly. The proposed scheme for synchronism is validated using commercial evaluation boards.Taking the proposed synchronization method as a starting point, a DAQ architecture for PET is defined that is composed of two types of module (acquisition and concentration) whose replication makes it possible to arrange a hierarchic system of arbitrary size, and circuit boards are designed and commissioned that implement a realization of the architecture for the...

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Timing Electronics and Fast Timing Methods with Scintillation Detectors

Cited by 68 publications

References 5 publications

Comparison of two experiments on radiative neutron decay

Comparison of two experiments on radiative neutron decay

Estudio e implementación de algoritmos digitales para la mejora de la resolución temporal en sistemas de tomografía por emisión de positrones

Development of a data acquisition architecture with distributed synchronization for a Positron Emission Tomography system with integrated front-end.

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