Measurement of carbon ion microdosimetric distributions with ultrathin 3D silicon diodes

Gómez, F.; Fleta, C.; Esteban, S.; Quirion, D.; Pellegrini, G.; Lozano, M.; Prezado, Yolanda; Santos, M. Dos; Guardiola, Consuelo; Montarou, G.; Prieto-Pena, Juan; Pardo-Montero, Juan

doi:10.1088/0031-9155/61/11/4036

Cited by 18 publications

(18 citation statements)

References 20 publications

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“…More information about the fabrication process and Technological Computed Assist Design (TCAD) simulations of the depletion volume and charge collection can be found at (Fleta, Esteban, Baselga, Quirion, Pellegrini, Guardiola, Cortés-Giraldo, López, Ramos, Gómez et al 2015). These detectors are designed to perform microdosimetric measurement at nominal fluence rate in hadrontherapy, allowing an instrumental verification of the lineal energy spectra at different depth and positions in a phantom (Gómez, Fleta, Esteban, Quirion, Pellegrini, Lozano, Prezado, Dos Santos, Guardiola, Montarou et al 2016, Prieto-Pena, Gómez, Fleta, Guardiola, Pellegrini, Donetti, Giordanengo, González-Castaño & Pardo-Montero 2019. Their design produces a high conformation of the depleted region to a volume of approximately 900 µm 3 .…”

Section: Silicon Microdosimetermentioning

confidence: 99%

Impact of charge collection efficiency and electronic noise on the performance of solid-state 3D microdetectors

et al. 2020

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Microdosimetry has been traditionally performed through gaseous proportional counters, although in recent years different solid-state microdosimeters have been proposed and constructed for this task. In this paper, we analyze the response of solid-state devices of micrometric size with no intrinsic gain developed by CNM-CSIC (Spain). There are two major aspects of the operation of these devices that affect the reconstruction of the probability distributions and momenta of stochastic quantities related to microdosimetry. For micrometric volumes, the drift and diffusion of the charge carriers gives rise to a partial charge collection efficiency in the peripheral region of the depleted volume. This effect produces a perturbation of the reconstructed pulse height (i.e. imparted energy) distributions with respect to the actual microdosimetric distributions. The relevance of this deviation depends on the size, geometry and operating conditions of the device. On the other hand, the electronic noise from the single-event readout set-up poses a limit on the minimum detectable lineal energy when the microdosimeter size is reduced. This article addresses these issues to provide a framework on the physical constraints for the design and operation of solid-state microdosimeters.

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Section: Silicon Microdosimetermentioning

confidence: 99%

Impact of charge collection efficiency and electronic noise on the performance of solid-state 3D microdetectors

et al. 2020

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“…This model can estimate α and β in a linear‐quadric (LQ) model for any ion species and kinetic energy based on dose within a microregion. In the MK model, dose in the microregion is called the “specific energy.” The specific energy, which is essential in the MK model, has been measured using a tissue‐equivalent proportional chamber (TEPC), wall‐less TEPC, diamond detector, silicon diode, and track‐etched detectors . Numerical calculations based on a Kiefer–Chatterjee model of microdosimetry, and Monte Carlo simulation with PHITS have also been used for obtaining specific energy.…”

Section: Introductionmentioning

confidence: 99%

Estimations of relative biological effectiveness of secondary fragments in carbon ion irradiation of water using CR‐39 plastic detector and microdosimetric kinetic model

et al. 2019

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Purpose To estimate relative biological effectiveness (RBE) ascribed to secondary fragments in a lateral distribution of carbon ion irradiation. The RBE was estimated with the microdosimetric kinetic (MK) model and measured linear energy transfer (LET) obtained with CR‐39 plastic detectors. Methods A water phantom was irradiated by a 12C pencil beam with energy of 380 MeV/u at the Gunma University Heavy Ion Medical Center (GHMC), and CR‐39 detectors were exposed to secondary fragments. Because CR‐39 was insensitive to low LET, we conducted Monte Carlo simulations with Geant4 to calculate low LET particles. The spectra of low LET particles were combined with experimental spectra to calculate RBE. To estimate accuracy of RBE, we calculated RBE by changing yield of low LET particles by ± 10% and ± 40%. Results At a small angle, maximum RBE by secondary fragments was 1.3 for 10% survival fractions. RBE values of fragments gradually decreased as the angle became larger. The shape of the LET spectra in the simulation reproduced the experimental spectra, but there was a discrepancy between the simulation and experiment for the relative yield of fragments. When the yield of low LET particles was changed by ± 40%, the change in RBE was smaller than 10%. Conclusions An RBE of 1.3 was expected for secondary fragments emitted at a small angle. Although, we observed a discrepancy in the relative yield of secondary fragments between simulation and experiment, precision of RBE was not so sensitive to the yield of low LET particles.

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“…In particular, two different types of 3D silicon microdosimeters were manufactured at IMB-CNM. The first one belongs to the U3DTHIN architecture [35,37,50,[57][58][59]. On the basis of the preliminary results with U3DTHIN detectors, a novel architecture based on 3D-cylindrical microstructures was proposed and specifically developed for microdosimetry in hadron therapy [32][33][34]36,[38][39][40][41].…”

Section: Silicon-based 3d Microdosimetersmentioning

confidence: 99%

“…For this purpose, we designed and fabricated novel radiation detectors with both 3D and 3D-cylindrical architectures, which were etched inside the silicon bulk in the National Center of Microelectronics (IMB-CNM, CSIC, Spain). These 3D microstructures were specifically customized for microdosimetry in PT and they overcame some of the technological challenges in this domain, namely the low noise capability, well-defined sensitive volume, high spatial resolution, and pile-up robustness [32][33][34][35][36][37][38][39][40][41]. Both architectures reduce the loss of charge carriers due to trapping effects, the charge collection time, and the voltage required for full depletion compared to planar silicon detectors.…”

Section: Introductionmentioning

confidence: 99%

Silicon 3D Microdetectors for Microdosimetry in Hadron Therapy

et al. 2020

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The present overview describes the evolution of new microdosimeters developed in the National Microelectronics Center in Spain (IMB-CNM, CSIC), ranging from the first ultra-thin 3D diodes (U3DTHINs) to the advanced 3D-cylindrical microdetectors, which have been developed over the last 10 years. In this work, we summarize the design, main manufacture processes, and electrical characterization of these devices. These sensors were specifically customized for use in particle therapy and overcame some of the technological challenges in this domain, namely the low noise capability, well-defined sensitive volume, high spatial resolution, and pile-up robustness. Likewise, both architectures reduce the loss of charge carriers due to trapping effects, the charge collection time, and the voltage required for full depletion compared to planar silicon detectors. In particular, a 3D‒cylindrical architecture with electrodes inserted into the silicon bulk and with a very well‒delimited sensitive volume (SV) mimicked a cell array with shapes and sizes similar to those of mammalian cells for the first time. Experimental tests of the carbon beamlines at the Grand Accélérateur National d’Lourds (GANIL, France) and Centro Nazionale Adroterapia Oncologica (CNAO, Italy) showed the feasibility of the U3DTHINs in hadron therapy beams and the good performance of the 3D‒cylindrical microdetectors for assessing linear energy distributions of clinical beams, with clinical fluence rates of 5 × 107 s−1cm−2 without saturation. The dose-averaged lineal energies showed a generally good agreement with Monte Carlo simulations. The results indicated that these devices can be used to characterize the microdosimetric properties in hadron therapy, even though the charge collection efficiency (CCE) and electronic noise may pose limitations on their performance, which is studied and discussed herein. In the last 3D‒cylindrical microdetector generation, we considerably improved the CCE due to the microfabrication enhancements, which have led to shallower and steeper dopant profiles. We also summarize the successive microdosimetric characterizations performed with both devices in proton and carbon beamlines.

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Measurement of carbon ion microdosimetric distributions with ultrathin 3D silicon diodes

Cited by 18 publications

References 20 publications

Impact of charge collection efficiency and electronic noise on the performance of solid-state 3D microdetectors

Impact of charge collection efficiency and electronic noise on the performance of solid-state 3D microdetectors

Estimations of relative biological effectiveness of secondary fragments in carbon ion irradiation of water using CR‐39 plastic detector and microdosimetric kinetic model

Silicon 3D Microdetectors for Microdosimetry in Hadron Therapy

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