• Title/Summary/Keyword: pulse detector

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Driving Method of Ultraviolet Sensor for Fire alarms using Pulse Width Modulation (PWM을 이용한 화재 감지를 위한 자외선 센서의 구동 방법)

  • Lim, Byung-Hyun;Ko, Nak-Yong;Hwang, Jong-Sun;Kim, Yeong-Min
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05c
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    • pp.31-35
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    • 2004
  • We propose driving method of Ultraviolet sensor for fire alarms using pulse width modulation that used to fire detector with sensor of private-use detectable light energy as ultraviolet in energy of electromagnetic-wave type radiate from flame, when combustible burn with contain carbon,. Ultraviolet sensor is UV Tron using gas multiplication effect to current discharge and photoelectric effect of metal. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research designed driving circuit with UV sensors and proposed method of false alarm reduced to resemble fire. the result propers the prevention and extinction of fire technique degree, certificated operation of detector.

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Non-iterative pulse tail extrapolation algorithms for correcting nuclear pulse pile-up

  • Mohammad-Reza Mohammadian-Behbahani
    • Nuclear Engineering and Technology
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    • v.55 no.12
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    • pp.4350-4356
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    • 2023
  • Radiation detection systems working at high count rates suffer from the overlapping of their output electric pulses, known as pulse pile-up phenomenon, resulting in spectrum distortion and degradation of the energy resolution. Pulse tail extrapolation is a pile-up correction method which tries to restore the shifted baseline of a piled-up pulse by extrapolating the overlapped part of its preceding pulse. This needs a mathematical model which is almost always nonlinear, fitted usually by a nonlinear least squares (NLS) technique. NLS is an iterative, potentially time-consuming method. The main idea of the present study is to replace the NLS technique by an integration-based non-iterative method (NIM) for pulse tail extrapolation by an exponential model. The idea of linear extrapolation, as another non-iterative method, is also investigated. Analysis of experimental data of a NaI(Tl) radiation detector shows that the proposed non-iterative method is able to provide a corrected spectrum quite similar with the NLS method, with a dramatically reduced computation time and complexity of the algorithm. The linear extrapolation approach suffers from a poor energy resolution and throughput rate in comparison with NIM and NLS techniques, but provides the shortest computation time.

Determination of energy resolution for a NaI(Tl) detector modeled with FLUKA code

  • Demir, Nilgun;Kuluozturk, Zehra Nur
    • Nuclear Engineering and Technology
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    • v.53 no.11
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    • pp.3759-3763
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    • 2021
  • In this study, 3" × 3" NaI(Tl) detector, which is widely used in gamma spectroscopy, was modeled with FLUKA code, and calculations required to determine the detector's energy resolution were reported. Photon beams with isotropic distribution with 59, 81, 302, 356, 511, 662, 835, 1173, 1275, and 1332 keV energy were used as radiation sources. The photon pulse height distribution of the NaI(Tl) without influence of its energy resolution obtained with FLUKA code has been converted into a real NaI(Tl) response function, using the necessary conversion process. The photon pulse height distribution simulated in the conversion process was analyzed using the ROOT data analysis framework. The statistical errors of the simulated data were found in the range of 0.2-1.1%. When the results, obtained with FLUKA and ROOT, are compared with the literature data, it is seen that the results are in good agreement with them. Thus, the applicability of this procedure has been demonstrated for the other energy values mentioned.

5-GHz Delay-Locked Loop Using Relative Comparison Quadrature Phase Detector

  • Wang, Sung-Ho;Kim, Jung-Tae;Hur, Chang-Wu
    • Journal of information and communication convergence engineering
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    • v.2 no.2
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    • pp.102-105
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    • 2004
  • A Quadrature phase detector for high-speed delay-locked loop is introduced. The proposed Quadrature phase detector is composed of two nor gates and it determines if the phase difference of two input clocks is 90 degrees or not. The delay locked loop circuit including the Quadrature phase detector is fabricated in a 0.18 um Standard CMOS process and it operates at 5 GHz frequency. The phase error of the delay-locked loop is maximum 2 degrees and the circuits are robust with voltage, temperature variations.

Playback Signal Processing in a Digital High Density Magnetic Recording System (디지털 고밀도 자기기록 장치의 재생신호 처리에 관한 연구)

  • 이상록;박시우;박선기;박진우
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.12
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    • pp.31-39
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    • 1993
  • In the playback signal processing of a digital magnetic recording system, the major signal processing processes consist of pulse equalization. pulse detection, clock recovery, and data recovery. Equalizer which compensates interference occurrde between pulses recorded in high density on a magnetic media is realized by pulse slimming method, and pulse detection by a integrating detector. Clock recovery from the detector output was accomplished by using PLL. and data recovery to reduce noise effects was carried out by utilizing the three sampling clocks recovered in clock recovery process. In this paper these processes are implemented in hardware and its performance is evaluated by experimenting with a commercial DAT. It was found that the playback signal processor proposed is suitable to the practical high density magnetic recording system.

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Phoswich Detector for Simultaneous Measuring Alpha/beta Particles (알파/베타선 동시측정용 phoswich 검출기)

  • Kim, Gye-Hong;Park, Chan-Hee;Lee, Kune-Woo;Jung, Chong-Hun;Seo, Bum-Kyoung
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.6 no.2
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    • pp.111-117
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    • 2008
  • The new type phoswich detector consisting of the ZnS(Ag) and plastic scintillator for alpha/beta-ray simultaneous counting was developed for monitoring radiological contamination inside pipes. The detection performance was estimated using the PSD (pulse shape discrimination) method as a function of distance between the scintillator and radioactive source. The attenuation of particles traveling through a thin film for preventing the detector from being contaminated was experimentally estimated. It is concluded from our investigation that the phoswich detector developed can provide a sufficient alpha/beta-ray discrimination. The application of a thin film for preventing the detector from being contaminated was proven to be feasible.

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Coil Design of Pulse Induction Metal Detector (펄스 유도 방식의 금속탐지기 코일 설계)

  • Jung, Byung-Min;Chang, Yu-Shin;Han, Seung-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.4
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    • pp.389-396
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    • 2015
  • A coil design of pulse induction metal detectors has been described. The search coil was demonstrated by using the wire with the diameter of 0.3 mm, 0.5 mm and 1.0 mm and the dielectric plate with the $30cm{\times}30cm$ and $35cm{\times}35cm$, the time constant and the currents of the coil as the variation of the coil size and the number of coil turns was characterized. The coil parameters like the resistance, the inductance and the time constants as the variation of the diameter of the wire, the coil size and the number of coil turns were compared and analysed through the calculation and the measurement. In addition, investigating the coil currents as the variation of the input pulse width, the coil design of pulse induction metal detectors has been discussed.

Design of a Clock and Data Recovery Circuit Using the Multi-point Phase Detector (다중점 위상검출기를 이용한 클럭 및 데이터 복원회로 설계)

  • Yoo, Sun-Geon;Kim, Seok-Man;Kim, Doo-Hwan;Cho, Kyoung-Rok
    • The Journal of the Korea Contents Association
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    • v.10 no.2
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    • pp.72-80
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    • 2010
  • The 1Gbps clock and data recovery (CDR) circuit using the proposed multi-point phase detector (PD) is presented. The proposed phase detector generates up/down signals comparing 3-point that is data transition point and clock rising/falling edge. The conventional PD uses the pulse width modulation (PWM) that controls the voltage controlled oscillator (VCO) using the width of a pulse period's multiple. However, the proposed PD uses the pulse number modulation (PNM) that regulates the VCO with the number of half clock cycle pulse. Therefore the proposed PD can controls VCO preciously and reduces the jitter. The CDR circuit is tested using 1Gbps $2^{31}-1$ pseudo random bit sequence (PRBS) input data. The designed CDR circuit shows that is capable of recovering clock and data at rates of 1Gbps. The recovered clock jitter is 7.36ps at 1GHz and the total power consumption is about 12mW. The proposed circuit is implemented using a 0.18um CMOS process under 1.8V supply.

Design of a Low-Power MOS Monolithic Peak Detector (저전력 MOS 모놀리식 피크 감지기의 설계)

  • 박광민;백경호
    • Proceedings of the IEEK Conference
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    • 2000.06b
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    • pp.217-220
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    • 2000
  • In this paper, A low-power MOS monolithic peak detector is presented. Designed for monolithic and low-power characteristics, this MOS peak detector can be integrated easily on the same chip as a module of large communication systems. The simulation results of this peak detector which was composed with four NMOSs and two capacitors show the power dissipation of 0.972㎽ and the good operations for 2㎓ operating pulse frequency. Therefore, it may be used as a functional block for various signal processing systems.

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Pulse pileup correction method for gamma-ray spectroscopy in high radiation fields

  • Lee, Minju;Lee, Daehee;Ko, Eunbie;Park, Kyeongjin;Kim, Junhyuk;Ko, Kilyoung;Sharma, Manish;Cho, Gyuseong
    • Nuclear Engineering and Technology
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    • v.52 no.5
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    • pp.1029-1035
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    • 2020
  • The detector suffers from pulse pileup by overlapping of the signals when it was used in high radiation fields. The pulse pileup deteriorates the energy spectrum and causes count losses due to random co-incidences, which might not resolve within the resolving time of the detection system. In this study, it is aimed to propose a new pulse pileup correction method. The proposed method is to correct the start point of the pileup pulse. The parameters are obtained from the fitted exponential curve using the peak point of the previous pulse and the start point of the pileup pulse. The amplitude at the corrected start point of the pileup pulse can be estimated by the peak time of the pileup pulse. The system is composed of a NaI (Tl) scintillation crystal, a photomultiplier tube, and an oscilloscope. A 61 μCi 137Cs check-source was placed at a distance of 3 cm, 5 cm, and 10 cm, respectively. The gamma energy spectra for the radioisotope of 137Cs were obtained to verify the proposed method. As a result, the correction of the pulse pileup through the proposed method shows a remarkable improvement of FWHM at 662 keV by 29, 39, and 7%, respectively.