scholarly journals A Study on the Performance of a Silicon Photodiode Sensor for a Particle Dosimeter and Spectrometer

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8029
Author(s):  
Bobae Kim ◽  
Uk-Won Nam ◽  
Sunghwan Kim ◽  
Sukwon Youn ◽  
Won-Kee Park ◽  
...  
Keyword(s):  
Effective Area ◽  
Space Environment ◽  
Radiation Environment ◽  
Neutron Spectrometer ◽  
Silicon Photodiode ◽  
Analog To Digital ◽  
Tissue Equivalent ◽  
Silicon Sensors ◽  
Wide Range ◽  
Signal Readout

A lunar vehicle radiation dosimeter (LVRAD) has been proposed for studying the radiation environment on the lunar surface and evaluating its impact on human health. The LVRAD payload comprises four systems: a particle dosimeter and spectrometer (PDS), a tissue-equivalent dosimeter, a fast neutron spectrometer, and an epithermal neutron spectrometer. A silicon photodiode sensor with compact readout electronics was proposed for the PDS. The PDS system aims to measure protons with 10–100 MeV of energy and assess dose in the lunar space environment. The manufactured silicon photodiode sensor has an effective area of 20 mm × 20 mm and thickness of 650 μm; the electronics consist of an amplifier, analog pulse processor, and a 12-bit analog-to-digital converter for signal readout. We studied the responses of silicon sensors which were manufactured with self-made electronics to gamma rays with a wide range of energies and proton beams.

Analysis of electron-diffraction intensity profiles using a photodiode-array detection system

1983 ◽  
Vol 41 ◽  
pp. 322-323
Author(s):  
J. B. Warren
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Detection System ◽  
High Energy ◽  
Photographic Emulsion ◽  
Diffraction Intensity ◽  
Silicon Photodiode ◽  
Photodiode Array Detection ◽  
Analog To Digital ◽  
Photodiode Array

Electron diffraction intensity profiles have been used extensively in studies of polycrystalline and amorphous thin films. In previous work, diffraction intensity profiles were quantitized either by mechanically scanning the photographic emulsion with a densitometer or by using deflection coils to scan the diffraction pattern over a stationary detector. Such methods tend to be slow, and the intensities must still be converted from analog to digital form for quantitative analysis. The Instrumentation Division at Brookhaven has designed and constructed a electron diffractometer, based on a silicon photodiode array, that overcomes these disadvantages. The instrument is compact (Fig. 1), can be used with any unmodified electron microscope, and acquires the data in a form immediately accessible by microcomputer.Major components include a RETICON 1024 element photodiode array for the de tector, an Analog Devices MAS-1202 analog digital converter and a Digital Equipment LSI 11/2 microcomputer. The photodiode array cannot detect high energy electrons without damage so an f/1.4 lens is used to focus the phosphor screen image of the diffraction pattern on to the photodiode array.

New radiation environment and effects models in the European Space Agency's Space Environment Information System (SPENVIS)

Space Weather ◽  
2004 ◽  
Vol 2 (10) ◽  
pp. n/a-n/a ◽  
Author(s):  
D. Heynderickx ◽  
B. Quaghebeur ◽  
J. Wera ◽  
E. J. Daly ◽  
H. D. R. Evans
Keyword(s):  
Information System ◽  
Space Environment ◽  
Radiation Environment

scholarly journals Multiple sources of signal amplification within the B cell Ras/MAPK pathway

2018 ◽  
Author(s):  
Justin D. Mclaurin ◽  
Orion D. Weiner
Keyword(s):  
Positive Feedback ◽  
Signal Amplification ◽  
Mapk Pathway ◽  
Threshold Level ◽  
Cell Types ◽  
Multiple Sources ◽  
Analog To Digital ◽  
Ras Activation ◽  
Wide Range ◽  
Erk Activity

AbstractThe Ras-Map kinase (MAPK) cascade underlies functional decisions in a wide range of cell types and organisms. In B cells, positive feedback-driven Ras activation is the proposed source of the digital (all-or-none) MAPK responses following antigen stimulation. However, an inability to measure endogenous Ras activity in living cells has hampered our ability to test this model directly. Here we leverage biosensors of endogenous Ras and ERK activity to revisit this question. We find that BCR ligation drives switch-like Ras activation and that lower BCR signaling output is required for the maintenance versus the initiation of Ras activation. Surprisingly, digital ERK responses persist in the absence of positive feedback-mediated Ras activation, and digital ERK is observed at a threshold level of Ras activation. These data suggest an independent analog-to-digital switch downstream of Ras activation, and reveals that multiple sources of signal amplification exist within the Ras-ERK module of the BCR pathway.

Design of Robust Quantizers for Low-Bit Analog-to-Digital Converters for Gaussian Source

2019 ◽  
Vol 28 (supp01) ◽  
pp. 1940002 ◽  
Author(s):  
Milan R. Dinčić ◽  
Zoran H. Perić ◽  
Dragan B. Denić ◽  
Zoran Stamenković
Keyword(s):  
Energy Consumption ◽  
Communication Systems ◽  
Mimo Systems ◽  
Automatic Gain Control ◽  
Gain Control ◽  
Analog To Digital Converters ◽  
Signal Power ◽  
Analog To Digital ◽  
Wide Range ◽  
Gaussian Source

This paper considers the design of robust logarithmic [Formula: see text]-law companding quantizers for the use in analog-to-digital converters (ADCs) in communication system receivers. The quantizers are designed for signals with the Gaussian distribution, since signals at the receivers of communication systems can be very well modeled by this type of distribution. Furthermore, linearization of the logarithmic [Formula: see text]-law companding function is performed to simplify hardware implementation of the quantizers. In order to reduce energy consumption, low-resolution quantizers are considered (up to 5 bits per sample). The main advantage of these quantizers is high robustness — they can provide approximately constant SNR in a wide range of signal power (this is very important since the signal power at receivers can vary in wide range, due to fading and other transmission effects). Using the logarithmic [Formula: see text]-law companding quantizers there is no need for using automatic gain control (AGC), which reduces the implementation complexity and increases the speed of the ADCs due to the absence of AGC delay. Numerical results show that the proposed model achieves good performances, better than a uniform quantizer, especially in a wide range of signal power. The proposed low-bit ADCs can be used in MIMO and 5G massive MIMO systems, where due to very high operating frequencies and a large number of receiving channels (and consequently a large number of ADCs), the reduction of ADC complexity and energy consumption becomes a significant goal.

Air Splits Research of Multi-Sector Combustor With Flow Network Approach and Experiments

2019 ◽  
Author(s):  
Shanping Shen ◽  
Guoqian Song
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
Effective Area ◽  
Network Approach ◽  
Test Rig ◽  
Flow Network ◽  
Wide Range ◽  
Aero Engine ◽  
Annular Combustor ◽  
Good Agreement

Abstract Multi-sector combustor tests are essential to aero-engine annular combustor development. For the test rig design, it is necessary to ensure that the pressure drop and flow split to the various portions of multi-sector combustor are consistent with the combustor component. This paper introduces a new kind of multi-sector combustor rig. The diffuser system of the test rig is different with the combustor component. This test rig is simple in structure and easy to machine. To evaluate the flow split and pressure drop of the test rig, a 1D-flow network approach is applied to multi-sector combustor rig design. The calculated results show good agreement with the experiment data. In order to study whether the test rig can simulate flow split and pressure loss of combustor components, flow split and pressure loss under different design features are analyzed. Result shows that by changing the effective area of inner/outer annular inlet baffle and inner/outer bleed air plate, inner/outer liner pressure drop and the ratio of air flow to W31c can be changed in a wide range. Thus, this kind of multi-sector combustor rig is convenient to change the multi-sector combustor test rig design to meet the requirements of the pressure drop and flow split design of combustor component, even when the rig has been manufactured.

Performance of Elastomeric Silicones in Ablative and Space Environments

1966 ◽  
Vol 39 (4) ◽  
pp. 1247-1257 ◽  
Author(s):  
Clyde L. Whipple ◽  
John A. Thorne
Keyword(s):  
High Vacuum ◽  
Thermal Control ◽  
Heat Fluxes ◽  
Space Environment ◽  
Space Applications ◽  
Wide Range ◽  
Environmental Extremes ◽  
Temperature Ranges ◽  
Space Environments ◽  
Thermal Control Coatings

Abstract Elastomeric silicones are among the best materials available for many ablative and space applications. In ablative applications, these materials protect launching equipment, safeguard various parts of vehicles and spacecraft during flight, and shield re-entering spacecraft. Generally, elastomeric silicones are used where ablative conditions involve low to moderate heat fluxes and shear forces. Ablative characteristics of materials can vary widely depending on polymer type, fillers, and applications techniques, and no one elastomeric silicone will perform in a wide range of ablative missions. A good knowledge of the ablative characteristics of silicone materials is required to select the best candidates for a given application. In the space environment, silicones are often used for seals, thermal control coatings, potting materials, and other applications because they perform well over wide temperature ranges, and because they are inherently stable to high-vacuum and ultraviolet conditions. Data given in this paper illustrate that silicones show little weight loss or loss of properties on exposure to space environmental extremes. Furthermore, these losses can be made almost negligible by proper conditioning of the finished elastomer.

ACHIEVING A LINEAR DOSE RATE RESPONSE IN PULSE-MODE SILICON PHOTODIODE SCINTILLATION DETECTORS OVER A WIDE RANGE OF EXCITATIONS

2014 ◽  
Vol 27 ◽  
pp. 1460136
Author(s):  
LEWIS CARROLL
Keyword(s):  
Signal Processing ◽  
Dose Rate ◽  
Pulse Generator ◽  
Current Mode ◽  
Pulse Mode ◽  
Radioactive Material ◽  
Activity Levels ◽  
Silicon Photodiode ◽  
Processing Scheme ◽  
Wide Range

We are developing a new dose calibrator for nuclear pharmacies that can measure radioactivity in a vial or syringe without handling it directly or removing it from its transport shield “pig”. The calibrator's detector comprises twin opposing scintillating crystals coupled to Si photodiodes and current-amplifying trans-resistance amplifiers. Such a scheme is inherently linear with respect to dose rate over a wide range of radiation intensities, but accuracy at low activity levels may be impaired, beyond the effects of meager photon statistics, by baseline fluctuation and drift inevitably present in high-gain, current-mode photodiode amplifiers. The work described here is motivated by our desire to enhance accuracy at low excitations while maintaining linearity at high excitations. Thus, we are also evaluating a novel “pulse-mode” analog signal processing scheme that employs a linear threshold discriminator to virtually eliminate baseline fluctuation and drift. We will show the results of a side-by-side comparison of current-mode versus pulse-mode signal processing schemes, including perturbing factors affecting linearity and accuracy at very low and very high excitations. Bench testing over a wide range of excitations is done using a Poisson random pulse generator plus an LED light source to simulate excitations up to ∼106 detected counts per second without the need to handle and store large amounts of radioactive material.

scholarly journals Research Flights on Blue Origin's New Shepard

2021 ◽  
Vol 9 (1) ◽  
pp. 62-67
Author(s):  
Erika B. Wagner
Keyword(s):  
Form Factor ◽  
High Altitude ◽  
Launch Vehicle ◽  
Space Environment ◽  
Technology Readiness ◽  
Technology Readiness Level ◽  
Microgravity Research ◽  
Wide Range ◽  
Readiness Level ◽  
Research And Education

Abstract Blue Origin's New Shepard launch vehicle made its first flight above the Kármán Line, returning safely to Earth in November 2015. At the time when this paper is being written (February 2021), the system has conducted 14 flights, including 10 with research and education payloads aboard. More than 100 payloads have exercised a wide range of capabilities and interfaces, from small cubesat-form factor student payloads to large custom payloads of nearly 100 kg. Investigations have spanned a wide range of high-altitude and microgravity research objectives, as well as raising technology readiness level (TRL) on diverse hardware. This paper summarizes New Shepard's payload missions to date, and presents standardized and custom accommodations, both in the shirtsleeve cabin and directly exposed to the space environment.

scholarly journals Logic Control of Static Excitation System in Power Alternators using PLC

2019 ◽  
Vol 8 (6) ◽  
pp. 3971-3978
Keyword(s):  
Closed Loop ◽  
Pulse Generator ◽  
Efficient Design ◽  
Excitation System ◽  
Efficient Manner ◽  
Loop Control ◽  
Analog To Digital ◽  
Logic Control ◽  
Wide Range ◽  
Pulse Amplifier

Logic control of Static Excitation System (SES) in Power Alternators deals with the use of PLC to control the terminal output voltage of the Alternator in a more simplified and efficient manner using a closed loop system. A closed loop control with negative feedback is designed, which involves AVR, Pulse Generator, Pulse Amplifier, Limiters, Power System Stabilizers with an Auto and a Manual channel. Disruption in the terminal voltage is caused by faults. These faults were rectified earlier by Electro Mechanical relays. Now we are at a major technological Change of Analog to Digital control. It reduces the complexity of the control system, and eliminates the need of wide range of contactors and coils to energies the relay. The best way to maintain the stability of the system is to identify the need and rectify it. This paper proposes an easy and an efficient design for fault detection and elimination using PLC based excitation system in power alternators.

scholarly journals Analysis of programs for calculation of the system characteristics of ultra-wide range receiving paths

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 75-80
Author(s):  
D. V. Arkhipenkov
Keyword(s):  
Integrated Circuits ◽  
Dynamic Range ◽  
Noise Figure ◽  
Third Order ◽  
Analog To Digital ◽  
Nonlinear Distortions ◽  
Wide Range ◽  
Real Value ◽  
Element Base ◽  
System Characteristics

When designing radio engineering products, at the early stages,one of the most important tasks to be solved is to determine the effective version of the system/device by analyzing all possible available versions. Therefore, the development of such systems / devices is a complex and time-consuming process, which involves an infinitely large number of iterations of calculations and simulations of various options in search of an optimal and  efficient  one.  This  article  describes  the  programs:  AppCAD from  Agilent  and  ADISimRF  from  Analog Devices. These programs have a large functionality, a lot of calculated system characteristics of the path, but each of them has shortcomings, for example, the lack of an editable database of integrated circuits (IC), the lack of dynamic range calculations for third-order intermodulation of the receiving path, theinability to optimize for nonlinear  distortions,  etc.The  purpose  of  the  article  is  to  develop  an  original  program  for  calculating  radio receiving  paths,  which  is  not  inferior  in  functionality  to  foreign  analogues  and  has  a  number  of  useful refinements for calculations. The article presents formulas forcalculating the noise figure of an analog-to-digital converter (ADC) and makes a comparative analysis of the resultsobtained with the real value. The noise figure of the radio receiving path is refined by including the reverseloss coefficient and the ADC noise figure in the formula. The program developed by the author of the article hasan editable element base, which simplifies and accelerates the calculation of the device. The algorithm of theprogram developed by the author is described, and the calculation of the system characteristics of the path for comparison with foreign analogues is given.

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