Research

12 pages, 10699 KiB

Open AccessArticle

Energy Resolution from a Silicon Detector’s Interstrip Regions

by J. A. Dueñas, A. Cobo, F. Galtarossa, A. Goasduff, D. Mengoni and A. M. Sánchez-Benítez

Sensors 2024, 24(8), 2622; https://doi.org/10.3390/s24082622 - 19 Apr 2024

Viewed by 190

In this work, we present a novel approach for improving the energy resolution from particles impinging on the interstrip regions of silicon strip detectors. We employed three double-sided strip detectors from the GRIT array and a triple

α

-source under laboratory conditions. The [...] Read more.

In this work, we present a novel approach for improving the energy resolution from particles impinging on the interstrip regions of silicon strip detectors. We employed three double-sided strip detectors from the GRIT array and a triple

α

-source under laboratory conditions. The results showed that the interstrip resolution depends not only on the impinging side but also on whether it is a P- or an N-interstrip. We obtained the interstrip energy resolution down to 0.4%, and, depending on the scenario, the resolution was enhanced by a factor of 2. We believe that this new rotation method allows for the possibility of applying particle identification methods on interstrip events, which in most cases are dismissed during data recording. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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12 pages, 487 KiB

Open AccessArticle

Temperature Peak-Drift Correction Method for NaI(Tl) Detectors Using the Background Peak

by Songlin Wen and Rong Zhou

Sensors 2024, 24(8), 2621; https://doi.org/10.3390/s24082621 - 19 Apr 2024

Viewed by 165

Abstract

The overall gain of a scintillation detector is temperature-dependent, leading to a drift in the measured gamma energy spectrum with changes in temperature. To mitigate this effect, a temperature drift correction is essential prior to conducting gamma spectrum analysis. In this study, the [...] Read more.

The overall gain of a scintillation detector is temperature-dependent, leading to a drift in the measured gamma energy spectrum with changes in temperature. To mitigate this effect, a temperature drift correction is essential prior to conducting gamma spectrum analysis. In this study, the detector gain ratio is determined by comparing the positions of the same background peak across different spectra. Subsequently, the original spectrum is adjusted accordingly to obtain a gamma spectrum free from temperature drift. Experimental results demonstrate that after implementing this correction, the relative deviation of the ⁵⁷Co characteristic peak positions in the gamma spectrum measured by the NaI(Tl) detector is reduced from 18.64% to 0.91%. Furthermore, by performing energy calibration beforehand, the characteristic peak position can be utilized for secondary correction, further minimizing temperature drift. Our findings indicate that the relative deviation of the ²²Na characteristic peak positions was reduced, respectively, to 0.51% and 0.46% through secondary correction. This approach, which utilizes the background peak for correction, avoids the need for additional radioactivity or circuitry and effectively mitigates peak drift. Overall, this method holds significant implications for enhancing the accuracy of gamma spectrum analysis. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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21 pages, 3069 KiB

Open AccessArticle

Investigation of the Influence of Infrared Illumination on the Pulse Shapes of Output Signals of CdZnTe Detectors

by Victor Ivanov, Viktors Fjodorovs, Sergejs Hinoverovs, Anatoli Loutchanski, Vadims Ogorodniks and Sergejs Vidinejevs

Sensors 2023, 23(24), 9863; https://doi.org/10.3390/s23249863 - 16 Dec 2023

Viewed by 562

Abstract

The spectrometric characteristics of CdZnTe detectors are largely determined by the nonuniformity of the material and the influence of the negative polarization effects associated with the formation of space charges in the sensitive volume of the detector. They change the electric field distribution [...] Read more.

The spectrometric characteristics of CdZnTe detectors are largely determined by the nonuniformity of the material and the influence of the negative polarization effects associated with the formation of space charges in the sensitive volume of the detector. They change the electric field distribution in the detector and affect the efficiency of the charge carrier collection. An analysis of the waveforms of the output pulses was used to investigate the uniformity of the charge collection and electric field distribution in the detectors when irradiated by the alpha particles. The influence of infrared (IR) illumination on these parameters was evaluated. IR illumination had no positive effect on the planar detector but greatly improved the charge collection in quasi-hemispherical detectors in the peripheral (corner) regions. The output pulse amplitude increased, and the rise time notably decreased. Polarization that occurred predominantly in the corner regions at low temperatures (from −30 °C to −20 °C) was eliminated using IR illumination. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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11 pages, 3284 KiB

Open AccessArticle

Development of a High-Efficiency Device for Thermal Neutron Detection Using a Sandwich of Two High-Purity ¹⁰B Enriched Layers

by Chiara Provenzano, Marcella Marra, Anna Paola Caricato, Paolo Finocchiaro, Simone Amaducci, Fabio Longhitano, Maurizio Martino, Gaetano Elio Poma and Gianluca Quarta

Sensors 2023, 23(24), 9831; https://doi.org/10.3390/s23249831 - 14 Dec 2023

Cited by 1 | Viewed by 554

Abstract

The shortage of

^{3}

He, a crucial element widely used as a neutron converter in neutron detection applications, has sparked significant research efforts aimed at finding alternative materials, developing appropriate deposition methods, and exploring new detector architectures. This issue has required the exploration [...] Read more.

The shortage of

^{3}

He, a crucial element widely used as a neutron converter in neutron detection applications, has sparked significant research efforts aimed at finding alternative materials, developing appropriate deposition methods, and exploring new detector architectures. This issue has required the exploration of novel approaches to address the challenges faced in neutron detection. Among the available conversion materials,

^{10}

B has emerged as one of the most promising choices due to its high neutron-capture cross-section and relatively high Q value. In our previous papers, we delved into the possibility of depositing neutron conversion layers based on

^{10}

B using Pulsed Laser Deposition (PLD). We investigated and evaluated the performance of these layers based on various factors, including deposition conditions, substrate properties, and film thickness. Moreover, we successfully developed and tested a device that employed a single conversion layer coupled with a silicon particle detector. In this current study, we present the development of a new device that showcases improved performance in terms of efficiency, sensitivity, and discrimination against

γ

background signals. The background signals can arise from the environment or be associated with the neutron field. To achieve these advancements, we considered a new detection geometry that incorporates the simultaneous use of two

^{10}

B conversion layers, each with a thickness of 1.5

μ

m, along with two solid-state silicon detectors. The primary objective of this design was to enhance the overall detection efficiency when compared to the single-layer geometry. By employing this novel setup, our results demonstrate a significant enhancement in the device’s performance when exposed to a neutron flux from an Am-Be neutron source, emitting a flux of approximately 2.2 × 10

^{6}

neutrons per second. Furthermore, we established a noteworthy agreement between the experimental data obtained and the simulation results. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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13 pages, 849 KiB

Open AccessArticle

Experimental Determination of the Charge Carrier Transport Models for Improving the Simulation of the HR GaAs:Cr Detectors’ Response

by Petr Smolyanskiy, Petr Burian, Mateusz Sitarz and Benedikt Bergmann

Sensors 2023, 23(15), 6886; https://doi.org/10.3390/s23156886 - 03 Aug 2023

Viewed by 626

Abstract

The response of Timepix3 detectors with 300 µm and 500 µm thick HR GaAs:Cr sensors was studied with particle beams at the Danish Centre for Particle Therapy in Aarhus, Denmark. Therefore, the detectors were irradiated at different angles with protons of 240 MeV. [...] Read more.

The response of Timepix3 detectors with 300 µm and 500 µm thick HR GaAs:Cr sensors was studied with particle beams at the Danish Centre for Particle Therapy in Aarhus, Denmark. Therefore, the detectors were irradiated at different angles with protons of 240 MeV. The precise per-pixel time and energy measurements were exploited in order to determine the charge carrier transport properties. Using the tracks left by the penetrating charged particles hitting the sensor at the grazing angle, we were able to determine the charge collection efficiency, the charge carrier drift times across the sensor thickness, the dependency of the electron, and for the first time, the hole drift velocity on the electric field. Moreover, extracting the dependence of the charge cloud size on the interaction depth for different bias voltages, it was possible to determine the dependence of the diffusion coefficient on the applied bias voltage. A good agreement was found with the previously reported values for n-type GaAs. The measurements were conducted for different detector assemblies to estimate the systematic differences between them, and to generalize the results. The experimental findings were implemented into the Allpix Squared simulation framework and validated by a comparison of the measurement and simulation for the

^{241}

Am

γ

-ray source. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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13 pages, 5560 KiB

Open AccessArticle

Exploring the Interpad Gap Region in Ultra-Fast Silicon Detectors: Insights into Isolation Structure and Electric Field Effects on Charge Multiplication

by Gordana Laštovička-Medin, Mateusz Rebarz, Jovana Doknic, Ivona Bozovic, Gregor Kramberger, Tomáš Laštovička and Jakob Andreasson

Sensors 2023, 23(15), 6746; https://doi.org/10.3390/s23156746 - 28 Jul 2023

Cited by 1 | Viewed by 2282

Abstract

We present an in-depth investigation of the interpad (IP) gap region in the ultra-fast silicon detector (UFSD) Type 10, utilizing a femtosecond laser beam and the transient current technique (TCT) as probing instruments. The sensor, fabricated in the trench-isolated TI-LGAD RD50 production batch [...] Read more.

We present an in-depth investigation of the interpad (IP) gap region in the ultra-fast silicon detector (UFSD) Type 10, utilizing a femtosecond laser beam and the transient current technique (TCT) as probing instruments. The sensor, fabricated in the trench-isolated TI-LGAD RD50 production batch at the FBK Foundry, enables a direct comparison between TI-LGAD and standard UFSD structures. This research aims to elucidate the isolation structure in the IP region and measure the IP distance between pads, comparing it to the nominal value provided by the vendor. Our findings reveal an unexpectedly strong signal induced near p-stops. This effect is amplified with increasing laser power, suggesting significant avalanche multiplication, and is also observed at moderate laser intensity and high HV bias. This investigation contributes valuable insights into the IP region’s isolation structure and electric field effects on charge collection, providing critical data for the development of advanced sensor technology for the Compact Muon Selenoid (CMS) experiment and other high-precision applications. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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18 pages, 14707 KiB

Open AccessArticle

A Comprehensive Characterization of the TI-LGAD Technology

by Matias Senger, Anna Macchiolo, Ben Kilminster, Giovanni Paternoster, Matteo Centis Vignali and Giacomo Borghi

Sensors 2023, 23(13), 6225; https://doi.org/10.3390/s23136225 - 07 Jul 2023

Cited by 1 | Viewed by 1083

Abstract

Pixelated low-gain avalanche diodes (LGADs) can provide both precision spatial and temporal measurements for charged particle detection; however, electrical termination between the pixels yields a no-gain region, such that the active area or fill factor is not sufficient for small pixel sizes. Trench-isolated [...] Read more.

Pixelated low-gain avalanche diodes (LGADs) can provide both precision spatial and temporal measurements for charged particle detection; however, electrical termination between the pixels yields a no-gain region, such that the active area or fill factor is not sufficient for small pixel sizes. Trench-isolated LGADs (TI-LGADs) are a strong candidate for solving the fill-factor problem, as the p-stop termination structure is replaced by isolated trenches etched in the silicon itself. In the TI-LGAD process, the p-stop termination structure, typical of LGADs, is replaced by isolating trenches etched in the silicon itself. This modification substantially reduces the size of the no-gain region, thus enabling the implementation of small pixels with an adequate fill factor value. In this article, a systematic characterization of the TI-RD50 production, the first of its kind entirely dedicated to the TI-LGAD technology, is presented. Designs are ranked according to their measured inter-pixel distance, and the time resolution is compared against the regular LGAD technology. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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23 pages, 12857 KiB

Open AccessArticle

Optimizing Time Resolution Electronics for DMAPs

by Enrique López-Morillo, Clara Luján-Martínez, José Hinojo-Montero, Fernando Márquez-Lasso, Francisco Rogelio Palomo and Fernando Muñoz-Chavero

Sensors 2023, 23(13), 5844; https://doi.org/10.3390/s23135844 - 23 Jun 2023

Viewed by 903

Abstract

Depleted Monolithic Active Pixel Sensors (DMAPSs) are foreseen as an interesting choice for future high-energy physics experiments, mainly because of the reduced fabrication costs. However, they generally offer limited time resolution due to the stringent requirements of area and power consumption imposed by [...] Read more.

Depleted Monolithic Active Pixel Sensors (DMAPSs) are foreseen as an interesting choice for future high-energy physics experiments, mainly because of the reduced fabrication costs. However, they generally offer limited time resolution due to the stringent requirements of area and power consumption imposed by the targeted spatial resolution. This work describes a methodology to optimize the design of time-to-digital converter (TDC)-based timing electronics that takes advantage of the asymmetrical shape of the pulse at the output of the analog front-end (AFE). Following that methodology, a power and area efficient implementation fully compatible with the RD50-MPW3 solution is proposed. Simulation results show that the proposed solution offers a time resolution of 2.08 ns for a range of energies from 1000 e⁻ to 20,000 e⁻, with minimum area and zero quiescent in-pixel power consumption. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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16 pages, 3306 KiB

Open AccessArticle

Bistable Boron-Related Defect Associated with the Acceptor Removal Process in Irradiated p-Type Silicon—Electronic Properties of Configurational Transformations

by Andrei Nitescu, Cristina Besleaga, George Alexandru Nemnes and Ioana Pintilie

Sensors 2023, 23(12), 5725; https://doi.org/10.3390/s23125725 - 19 Jun 2023

Viewed by 969

Abstract

The acceptor removal process is the most detrimental effect encountered in irradiated boron-doped silicon. This process is caused by a radiation-induced boron-containing donor (BCD) defect with bistable properties that are reflected in the electrical measurements performed in usual ambient laboratory conditions. In this [...] Read more.

The acceptor removal process is the most detrimental effect encountered in irradiated boron-doped silicon. This process is caused by a radiation-induced boron-containing donor (BCD) defect with bistable properties that are reflected in the electrical measurements performed in usual ambient laboratory conditions. In this work, the electronic properties of the BCD defect in its two different configurations (A and B) and the kinetics behind transformations are determined from the variations in the capacitance-voltage characteristics in the 243–308 K temperature range. The changes in the depletion voltage are consistent with the variations in the BCD defect concentration in the A configuration, as measured with the thermally stimulated current technique. The A→B transformation takes place in non-equilibrium conditions when free carriers in excess are injected into the device. B→A reverse transformation occurs when the non-equilibrium free carriers are removed. Energy barriers of 0.36 eV and 0.94 eV are determined for the A→B and B→A configurational transformations, respectively. The determined transformation rates indicate that the defect conversions are accompanied by electron capture for the A→B conversion and by electron emission for the B→A transformation. A configuration coordinate diagram of the BCD defect transformations is proposed. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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12 pages, 4226 KiB

Open AccessArticle

A New Temperature Correction Method for NaI(Tl) Detectors Based on Pulse Deconvolution

by Jianming Xie, Liu Yang, Jinglun Li, Sheng Qi, Wenzhuo Chen, Hang Xu and Wuyun Xiao

Sensors 2023, 23(11), 5083; https://doi.org/10.3390/s23115083 - 26 May 2023

Viewed by 1181

Abstract

To overcome the temperature effect of NaI(Tl) detectors for energy spectrometry without additional hardware, a new correction method was put forward based on pulse deconvolution, trapezoidal shaping and amplitude correction, named DTSAC. To verify this method, actual pulses from a NaI(Tl)-PMT detector were [...] Read more.

To overcome the temperature effect of NaI(Tl) detectors for energy spectrometry without additional hardware, a new correction method was put forward based on pulse deconvolution, trapezoidal shaping and amplitude correction, named DTSAC. To verify this method, actual pulses from a NaI(Tl)-PMT detector were measured at various temperatures from −20 °C to 50 °C. Pulse processing and spectrum synthesis showed that the position drift of the ¹³⁷Cs 662 keV peak was less than 3 keV, and the corresponding resolution at 662 keV of the sum spectra ranged from 6.91% to 10.60% with the trapezoidal width set from 1000 ns to 100 ns. The DTSAC method corrects the temperature effect via pulse processing, and needs no reference peak, reference spectrum or additional circuits. The method solves the problem of correction of pulse shape and pulse amplitude at the same time, and can be used even at a high counting rate. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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13 pages, 2640 KiB

Open AccessArticle

Electric-Field Mapping of Optically Perturbed CdTe Radiation Detectors

by Adriano Cola, Lorenzo Dominici and Antonio Valletta

Sensors 2023, 23(10), 4795; https://doi.org/10.3390/s23104795 - 16 May 2023

Cited by 1 | Viewed by 1385

Abstract

In radiation detectors, the spatial distribution of the electric field plays a fundamental role in their operation. Access to this field distribution is of strategic importance, especially when investigating the perturbing effects induced by incident radiation. For example, one dangerous effect that prevents [...] Read more.

In radiation detectors, the spatial distribution of the electric field plays a fundamental role in their operation. Access to this field distribution is of strategic importance, especially when investigating the perturbing effects induced by incident radiation. For example, one dangerous effect that prevents their proper operation is the accumulation of internal space charge. Here, we probe the two-dimensional electric field in a Schottky CdTe detector using the Pockels effect and report on its local perturbation after exposure to an optical beam at the anode electrode. Our electro-optical imaging setup, together with a custom processing routine, allows the extraction of the electric-field vector maps and their dynamics during a voltage bias-optical exposure sequence. The results are in agreement with numerical simulations, allowing us to confirm a two-level model based on a dominant deep level. Such a simple model is indeed able to fully account for both the temporal and spatial dynamics of the perturbed electric field. This approach thus allows a deeper understanding of the main mechanisms affecting the non-equilibrium electric-field distribution in CdTe Schottky detectors, such as those leading to polarization. In the future, it could also be used to predict and improve the performance of planar or electrode-segmented detectors. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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11 pages, 3060 KiB

Open AccessArticle

General Purpose Transistor Characterized as Dosimetry Sensor of Proton Beams

by J. A. Moreno-Pérez, I. Ruiz-García, P. Martín-Holgado, A. Romero-Maestre, M. Anguiano, R. Vila and M. A. Carvajal

Sensors 2023, 23(7), 3771; https://doi.org/10.3390/s23073771 - 06 Apr 2023

Viewed by 1132

Abstract

A commercial pMOS transistor (MOSFET), 3N163 from Vishay (USA), has been characterized as a low-energy proton beam dosimeter. The top of the samples’ housing has been removed to guarantee that protons reached the sensitive area, that is, the silicon die. Irradiations took place [...] Read more.

A commercial pMOS transistor (MOSFET), 3N163 from Vishay (USA), has been characterized as a low-energy proton beam dosimeter. The top of the samples’ housing has been removed to guarantee that protons reached the sensitive area, that is, the silicon die. Irradiations took place at the National Accelerator Centre (Seville, Spain). During irradiations, the transistors were biased to improve the sensitivity, and the silicon temperature was monitored activating the parasitic diode of the MOSFET. Bias voltages of 0, 1, 5, and 10 V were applied to four sets of three transistors, obtaining an averaged sensitivity that was linearly dependent on this voltage. In addition, the short-fading effect was studied, and the uncertainty of this effect was obtained. The bias voltage that provided an acceptable sensitivity, (11.4 ± 0.9) mV/Gy, minimizing the uncertainty due to the fading effect (−0.09 ± 0.11) Gy was 1 V for a total absorbed dose of 40 Gy. Therefore, this off-the-shelf electronic device presents promising characteristics as a dosimeter sensor for proton beams. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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11 pages, 12341 KiB

Open AccessArticle

Inverse LGAD (iLGAD) Periphery Optimization for Surface Damage Irradiation

by Albert Doblas, David Flores, Salvador Hidalgo, Neil Moffat, Giulio Pellegrini, David Quirion, Jairo Villegas, Dzmitry Maneuski, Marie Ruat and Pablo Fajardo

Sensors 2023, 23(7), 3450; https://doi.org/10.3390/s23073450 - 25 Mar 2023

Cited by 1 | Viewed by 1160

Abstract

Pixelated LGADs have been established as the baseline technology for timing detectors for the High Granularity Timing Detector (HGTD) and the Endcap Timing Layer (ETL) of the ATLAS and CMS experiments, respectively. The drawback of segmenting an LGAD is the non-gain area present [...] Read more.

Pixelated LGADs have been established as the baseline technology for timing detectors for the High Granularity Timing Detector (HGTD) and the Endcap Timing Layer (ETL) of the ATLAS and CMS experiments, respectively. The drawback of segmenting an LGAD is the non-gain area present between pixels and the consequent reduction in the fill factor. To overcome this issue, the inverse LGAD (iLGAD) technology has been proposed by IMB-CNM to enhance the fill factor and provide excellent tracking capabilities. In this work, we explore the use of iLGAD sensors for surface damage irradiation by developing a new generation of iLGADs, the periphery of which is optimized to improve the performance of irradiated sensors. The fabricated iLGAD sensors exhibit good electrical performances before and after X-ray irradiation. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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11 pages, 2076 KiB

Open AccessArticle

Techniques for the Investigation of Segmented Sensors Using the Two Photon Absorption-Transient Current Technique

by Sebastian Pape, Esteban Currás, Marcos Fernández García and Michael Moll

Sensors 2023, 23(2), 962; https://doi.org/10.3390/s23020962 - 14 Jan 2023

Cited by 2 | Viewed by 1300

Abstract

The two photon absorption-transient current technique (TPA-TCT) was used to investigate a silicon strip detector with illumination from the top. Measurement and analysis techniques for the TPA-TCT of segmented devices are presented and discussed using a passive strip CMOS detector and a standard [...] Read more.

The two photon absorption-transient current technique (TPA-TCT) was used to investigate a silicon strip detector with illumination from the top. Measurement and analysis techniques for the TPA-TCT of segmented devices are presented and discussed using a passive strip CMOS detector and a standard strip detector as an example. The influence of laser beam clipping and reflection is shown, and a method that allows to compensate these intensity-related effects for investigation of the electric field is introduced and successfully employed. Additionally, the mirror technique is introduced, which exploits reflection at a metallised back side to enable the measurement directly below a top metallisation while illuminating from the top. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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15 pages, 27362 KiB

Open AccessArticle

3D Simulation, Electrical Characteristics and Customized Manufacturing Method for a Hemispherical Electrode Detector

by Manwen Liu, Wenzheng Cheng, Zheng Li, Zhenyang Zhao and Zhihua Li

Sensors 2022, 22(18), 6835; https://doi.org/10.3390/s22186835 - 09 Sep 2022

Cited by 2 | Viewed by 1543

Abstract

The theoretical basis of a hypothetical spherical electrode detector was investigated in our previous work. It was found that the proposed detector has very good electrical characteristics, such as greatly reduced full depletion voltage, small capacitance and ultra-fast collection time. However, due to [...] Read more.

The theoretical basis of a hypothetical spherical electrode detector was investigated in our previous work. It was found that the proposed detector has very good electrical characteristics, such as greatly reduced full depletion voltage, small capacitance and ultra-fast collection time. However, due to the limitations of current technology, spherical electrode detectors cannot be made. Therefore, in order to use existing CMOS technology to realize the fabrication of the detector, a hemispherical electrode detector is proposed. In this work, 3D modeling and simulation including potential and electric field distribution and hole concentration distribution are carried out using the TCAD simulation tools. In addition, the electrical characteristics, such as I-V, C-V, induced current and charge collection efficiency (CCE) with different radiation fluences, are studied to predict the radiation hardness property of the device. Furthermore, a customized manufacturing method is proposed and simulated with the TCAD-SPROCESS simulation tool. The key is to reasonably set the aspect ratio of the deep trench in the multi-step repetitive process and optimize parameters such as the angle, energy, and dose of ion implantation to realize the connection of the heavily doped region of the near-hemispherical electrode. Finally, the electrical characteristics of the process simulation are compared with the device simulation results to verify its feasibility. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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13 pages, 854 KiB

Open AccessArticle

Correction of Radiometry Data for Temperature Effect on Dark Current, with Application to Radiometers on Profiling Floats

by Terence O’Brien and Emmanuel Boss

Sensors 2022, 22(18), 6771; https://doi.org/10.3390/s22186771 - 07 Sep 2022

Cited by 4 | Viewed by 1333 | Correction

Abstract

Measurements of daytime radiometry in the ocean are necessary to constrain processes such as photosynthesis, photo-chemistry and radiative heating. Profiles of downwelling irradiance provide a means to compute the concentration of a variety of in-water constituents. However, radiometers record a non-negligible signal when [...] Read more.

Measurements of daytime radiometry in the ocean are necessary to constrain processes such as photosynthesis, photo-chemistry and radiative heating. Profiles of downwelling irradiance provide a means to compute the concentration of a variety of in-water constituents. However, radiometers record a non-negligible signal when no light is available, and this signal is temperature dependent (called the dark current). Here, we devise and evaluate two consistent methods for correction of BGC-Argo radiometry measurements for dark current: one based on measurements during the day, the other based on night measurements. A daytime data correction is needed because some floats never measure at night. The corrections are based on modeling the temperature of the radiometer and show an average bias in the measured value of nearly

0.01

W m

^{- 2}

nm

^{- 1}

, 3 orders of magnitude larger than the reported uncertainty of

2.5 \times 10^{- 5}

W m

^{- 2}

nm

^{- 1}

for the sensors deployed on BGC-Argo floats (SeaBird scientific OCR504 radiometers). The methods are designed to be simple and robust, requiring pressure, temperature and irradiance data. The correction based on nighttime profiles is recommended as the primary method as it captures dark measurements with the largest dynamic range of temperature. Surprisingly, more than 28% of daytime profiles (130,674 in total) were found to record significant downwelling irradiance at 240–250 dbar. The correction is shown to be small relative to near-surface radiance and thus most useful for studies investigating light fields in the twilight zone and the impacts of radiance on deep organisms. Based on these findings, we recommend that BGC-Argo floats profile occasionally at night and to depths greater than 250 dbar. We provide codes to perform the dark corrections. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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14 pages, 10412 KiB

Open AccessArticle

Optimal Design of Multiple Floating Rings for 3D Large-Area Trench Electrode Silicon Detector

by Wenzheng Cheng, Manwen Liu, Zheng Li, Zhenyang Zhao and Zhihua Li

Sensors 2022, 22(17), 6352; https://doi.org/10.3390/s22176352 - 24 Aug 2022

Cited by 1 | Viewed by 1346

Abstract

The 3D electrode silicon detector eliminates the limit of chip thickness, so it can reduce the electrode spacing (small area) and effectively improve the radiation hardness. In order to expand the application range of the 3D electrode detector, we first propose a 3D [...] Read more.

The 3D electrode silicon detector eliminates the limit of chip thickness, so it can reduce the electrode spacing (small area) and effectively improve the radiation hardness. In order to expand the application range of the 3D electrode detector, we first propose a 3D large-area silicon detector with a large sensitive volume, and realize multiple floating rings on the upper and lower surfaces of the detector. Due to the influence of different charge states and energy levels in the Si-SiO₂ interface system, the top and bottom of the 3D P+ electrode are more prone to avalanche breakdown in the 3D large-area detector before the detector is completely depleted or the carrier saturation drift velocity is reached. Moreover, the electric field distribution becomes very uneven under the influence of the oxide charge, resulting in non-equilibrium carriers that cannot drift in the optimal path parallel to the detector surface. In this paper, the effect of floating rings on the performance of a 3D large-area silicon detector is studied by TCAD simulation. It can increase avalanche breakdown voltage by 14 times in a non-irradiated environment, and can work safely in a moderate irradiated environment. The charge collection efficiency can be effectively improved by optimizing the drift path. Full article

(This article belongs to the Special Issue Radiation Sensors and Detectors: Materials, Principles and Applications)

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