Polarization Relaxation in KDP-Isomorph Ferroelectrics

1989 ◽  
Vol 166 ◽  
Author(s):  
Vicki Homer ◽  
Ronald Edge
Keyword(s):  
Dielectric Constant ◽  
Electric Fields ◽  
Curie Point ◽  
Bragg Peak ◽  
Low Frequency ◽  
Two Dimensional ◽  
Sensitive Detector ◽  
Capacitance Bridge ◽  
Position Sensitive ◽  
Sufficient Strength

ABSTRACTThe two-dimensional position sensitive detector at IPNS was used to probe the splitting of a single Bragg peak of the ferroelectric KD2PO4 (DKDP) at temperatures below the Curie point. The (440) peak was split into four components as the crystal itself divided into four domains. When the crystal was subjected to electric fields of sufficient strength and duration, these peaks would change in relative intensity, thus displaying the rearrangement of the domain structure as the crystal changed its level of polarization. Even at temperatures 15–20K below the Curie point, the polarized crystal was observed to relax back to an almost completely unpolarized state upon removal of the applied electric field. This indicates that the true coercive field for the crystal at this temperature was much smaller than values previously reported [l]. Low frequency dielectric constant studies using a capacitance bridge have since been conducted, which confirm and expand on these results.

On the use of a small two-dimensional position-sensitive detector in neutron diffraction

1989 ◽  
Vol 22 (6) ◽  
pp. 562-568 ◽  
Author(s):  
M. S. Lehmann ◽  
W. F. Kuhs ◽  
G. J. McIntyre ◽  
C. Wilkinson ◽  
J. R. Allibon
Keyword(s):  
Bragg Peak ◽  
Computation Time ◽  
Two Dimensional ◽  
Sensitive Detector ◽  
Data Array ◽  
Standard Data ◽  
Gas Detector ◽  
Position Sensitive ◽  
Set Up ◽  
Efficient Packing

A small position-sensitive 3He gas detector has been developed for diffraction studies using short-wavelength neutrons. It covers 32 × 32 pixels with a 2 mm resolution, which in the present set up corresponds to 0.25°, and the efficiency is 75% at a wavelength of 0.8 Å. The detector has been used for standard data collection, as well as for studies of twinned crystals and measurements involving parasitic reflections. In all cases it has improved the mode and speed of the measurement, with gain factors compared with single detectors which range from more than two in standard measurements to several hundred for the study of details of the Bragg peak(s). The computation time in data analysis and the storage of the data are no major limitations, partly due to the smallness of the data array, and partly due to efficient packing routines.

Research and Design of Laser Displacement Measurement Based on the PSD

2015 ◽  
Vol 719-720 ◽  
pp. 580-583
Author(s):  
Xin Wen Duan ◽  
Ye Sun
Keyword(s):  
Signal Processing ◽  
Output Signal ◽  
Position Sensitive Detector ◽  
Measuring System ◽  
Two Dimensional ◽  
Sensitive Detector ◽  
Position Measurement ◽  
Arithmetic Circuit ◽  
Position Information ◽  
Position Sensitive

This paper introduces a kind of measuring system based on two-dimensional position sensitive detector PSD and single-chip signal processing, and have discussed the key technology. Two-dimensional position sensitive detector (2 D-PSD) is a kind of testing device of light spot position information and the output signal is a kind of current signal related to the location information. PSD output signal processing circuits are usually made by the I/V conversion circuit ,the addition, the subtraction and division arithmetic circuit. System can quickly, accurately and easily realize the position measurement, with a simple implementation, low power consumption, fast response, etc, It can be applied to many remote laser center positioning measurement and general industrial control occasions.

Attitude measurement and simulation of two-dimensional position sensitive detector

Optik ◽  
2019 ◽  
Vol 184 ◽  
pp. 399-411
Author(s):  
Fan Zhang ◽  
Jin Liu ◽  
Haima Yang ◽  
Haishan Liu ◽  
Yuan Chen ◽  
...  
Keyword(s):  
Position Sensitive Detector ◽  
Attitude Measurement ◽  
Two Dimensional ◽  
Sensitive Detector ◽  
Position Sensitive

scholarly journals Modeling and Simulation of Two-Dimensional Position Sensitive Detector (PSD) Sensor

2019 ◽  
Vol 9 (1) ◽  
pp. 744-753
Keyword(s):  
Modeling And Simulation ◽  
High Speed ◽  
Incident Light ◽  
Two Dimensions ◽  
Position Sensitive Detector ◽  
Two Dimensional ◽  
Sensitive Detector ◽  
Discrete Elements ◽  
Dimensional Array ◽  
Position Sensitive

This paper presents Modeling and Simulation of Two-Dimensional Position Sensitive Detector (PSD) using MATLAB. PSD is an Optical Position Sensor (OPS) that can measure a position of a radiation spot in one or two-dimensions on a sensor surface. Unlike discrete elements such as Charge-Coupled Device (CCD), it provides continuous position data, features high position resolution and high-speed response which give this paper its importance. The sensor used consists of two-dimensional array of photodiodes. The sensor has four output photocurrents that change according to the position of incident radiation on the surface. The work is divided into three parts of Modeling and Simulation; the first part is a single photodiode, Second part is one-dimensional array of photodiodes and the third one is two-dimensional array of photodiodes. The tool used to do the simulation is MATLAB software because it is professional and accurate tool, it has photodiode element and it is possible to control the beam of incident light. This research can be useful for Acquisition; Pointing and Tracking (APT) systems where this sensor will give the necessary data to do tracking operation. Proteus software was also been used as a secondary tool.

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