• 한국컴퓨터정보학회논문지
• /
• 제22권10호
• /
• pp.19-26
• /
• 2017

In this paper, we propose an efficient image equipment implementation for the detector characteristics of various detectors by analyzing un-cooled thermal detector that exhibits nonlinear changes due to external temperature effects. First, we explain Thermal Electric Cooler for un-cooled detector temperature control system and Non-image correction methode for IR system. Second, we present the results of a study on an efficient control technique that can minimize the deterioration of image quality by controlling a un-cooled thermal detector without a thermal electric cooler(TEC) inside. Third, we suggest Image Correction Methods for Uncooled IR TECless Detector with Non-linear characteristics due to Temperature Change. So, we analyze and present the results of Image correction methods for various un-cooled thermal detector.

• Progress in Superconductivity
• /
• 제14권2호
• /
• pp.87-91
• /
• 2012

Metallic magnetic calorimeters (MMCs) are one of the most competitive low temperature detector (LTD) readout sensors. They have the advantages of high time resolution, no heat dissipation, and a wide range of operating temperature. We apply MMCs to our neutrinoless double beta decay ($0v{\beta}{\beta}$) search experiment. A $CaMoO_4$ crystal was employed as both a source of $0v{\beta}{\beta}$ and an energy absorber. The crystal was thermally connected to a MMC sensor. We set a simple thermal model for this detector and measured pulse shapes are compared with a numerical solution of the thermal model.

• 전자공학회논문지B
• /
• 제31B권1호
• /
• pp.49-56
• /
• 1994

This paper describes the design principles and methods of electronic processor for thermal imager with the SPRITE detector, operating in the 8-12 micron band. The thermal imager consists of a optical scanner containing the detector and an electrical signal processor. The optical scanner utilizing rotating polygon and oscillating mirror, is 2-dimensional serial/parallel scan type using 5 elements of the detector. And the electronic processor has pre-processing of 5 chnanel's thermal signal from the detector, and performs digital scan conversion to reform the parallel data stream into serial analog data compatible with conventional RS-170 video. Through the designed electronic processor, we have acquired a satisfactory thermal image. And the MRTD (Minimum Resolvable Temperature Difference) is 0.5$^{\circ}$K at 7.5 cycles/mm.

• 한국군사과학기술학회지
• /
• 제19권6호
• /
• pp.698-702
• /
• 2016

Thermal imager is now regarded as one of the key observation devices for ISR activities and getting important more and more. As other detectors, however, the thermal detectors also have maximum input and therefore they will be saturated if the input IR energy exceeds the allowed range. The saturation in the thermal detector makes it impossible to distinguish the target from background, as a result, the thermal imager does not perform its own mission anymore. In order to get an insight related with the image saturation, this paper develops a saturation model for a thermal imaging system, not a thermal detector. The proposed modeling starts from analyzing the specification of a thermal imager. Coupled with the characteristic parameters of the object, the saturation model can be used to predict the distance on which the detector is saturated. The proposed saturation model prove its validity by applying it for the case of observing a flash-bang.

• Nuclear Engineering and Technology
• /
• 제56권2호
• /
• pp.575-600
• /
• 2024

During an earthquake on December 29th 2020, the Krško NPP automatically shutdown due to the trigger of the negative neutron flux rate signal on the power range nuclear instrumentation. From the time course of the detector signal, it can be concluded that the fluctuation in the detector signal may have been caused by the mechanical movement of the ex-core neutron detectors or the pressure vessel components rather than the actual change in reactor power. The objective of the analysis was to evaluate the sensitivity of the neutron flux at the ex-core detector position, if the detector is moved in the radial or axial direction. In addition, the effect of the core barrel movement and core inside the baffle movement in the radial direction were analysed. The analysis is complemented by the calculation of the thermal and total neutron flux gradient in radial, axial and azimuthal directions. The Monte Carlo particle transport code MCNP was used to study the changes in the response of the ex-core detector for the above-mentioned scenarios. Power and intermediate-range detectors were analysed separately, because they are designed differently, positioned at different locations, and have different response characteristics. It was found that the movement of the power range ex-core detector has a negligible effect on the value of the thermal neutron flux in the active part of the detector. However, the radial movement of the intermediate-range detector by 5 cm results in 7%-8% change in the thermal neutron flux in the active part of the intermediate-range detector. The analysis continued with an evaluation of the effects of moving the entire core barrel on the ex-core detector response. It was estimated that the 2 mm core barrel radial oscillation results in ~4% deviation in the power and intermediate-range detector signal. The movement of the reactor core inside baffle can contribute ~6% deviation in the ex-core neutron detector signal. The analysis showed that the mechanical movement of ex-core neutron detectors cannot explain the fluctuations in the ex-core detector signal. However, combined core barrel and reactor core inside baffle oscillations could be a probable reason for the observed fluctuations in the ex-core detector signal during an earthquake.

• Nuclear Engineering and Technology
• /
• 제56권4호
• /
• pp.1425-1430
• /
• 2024

This study develops superheated emulsion detectors that are both sensitive to fast neutrons, and thermal neutrons owing to the exergonic ⁶₃Li(n, α)³₁H capture reaction caused by the ⁶Li-containing compound dispersed throughout the gel-like medium. The experimental research was conducted on two SEDs. One detector was an ordinary Freon-12 detector and the other was a Freon-12 detector containing 3.4 % (by weight) LiCl. In order to investigate the sensitivity of lithium-containing SEDs to thermal neutrons, two types of SEDs were simultaneously exposed to various flux levels of thermal neutrons from ²⁴¹Am-Be neutron source inside a cylindrical tank filled with water. A Boron-lined proportional counter was used to estimate the thermal neutron flux and the relevant MCNP code was developed for flux and dose calculations in the prepared set-up around ²⁴¹Am-Be source. The results demonstrate that there is a proportional relationship between the variations of SED response and the change in thermal neutron flux and dose. Also, the sensitivity of SED was estimated.

• Journal of Astronomy and Space Sciences
• /
• 제31권2호
• /
• pp.177-186
• /
• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA) detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL) mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.

• 한국군사과학기술학회지
• /
• 제13권4호
• /
• pp.542-550
• /
• 2010

Cooled infrared detector is widely used as the core part in a variety of the thermal imaging systems. For the selection of the highly reliable cooled infrared detector with good performance, it is necessary for us to possess the characterization methods of the well defined performance index of cooled infrared detector. In this paper, various performance index of the cooled infrared detector including reliability as well as the optical and cooling performance of cooled infrared detector are defined and their characterization methods will be investigated and implemented systematically.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2005년도 동계학술발표대회 논문집
• /
• pp.365-370
• /
• 2005

Infrared (lR) detectors are widely used for such applications as thermoelstic stress analysis, medical diagnostics and temperature measurement. Infrared detectors commonly need to be refrigerated below 80 K, and thus a cooling system should be equipped together with the detector system. The cooling load, which should be removed by the cooling system to maintain the nominal operating temperature of the detector, critically depends on the insulation efficiency of the cryochamber housing the detector. Cryochamber considers the conduction heat transfer through a cold finger, the gases conduction and radiation heat transfer. The thermal loads of an infrared detector Cryochamber with radiation shield are investigated experimentally in present study. Since the effect of radiation heat transfer on thermal loads is significant, radiation shields is installed in the cold finger part to protect heat input through radiation. It is found that the thermal load can be substantially reduced by increasing the number of radiation shield.

• 설비공학논문집
• /
• 제20권1호
• /
• pp.11-16
• /
• 2008

Infrared (IR) detectors are widely used for such applications as thermoelastic stress analysis, medical diagnostics and temperature measurement. Infrared detectors commonly need to be refrigerated below 80 K, and thus a cooling system should be equipped together with the detector system. The cooling load, which should be removed by the cooling system to maintain the nominal operating temperature of the detector, critically depends on the insulation efficiency of the cryochamber housing the detector. Thermal load of a cryochamber is attributed to the conduction heat transfer through a cold finger, the gases conduction and radiation heat transfer. The thermal loads of an infrared detector cryochamber with a radiation shield are investigated experimentally in present study. Since the effect of radiation heat transfer on thermal loads is significant, radiation shields is installed in the cold finger part to protect heat input through radiation.