Procedures for Wavelength Calibration and Spectral Response Correction of CCD Array Spectrometers

This work describes a procedure for acquiring a spectrum of an analyte over an extended range of wavelengths and validating the wavelength and intensity assignments. To acquire a spectrum over an extended range of wavelengths with a spectrometer with a charge coupled device (CCD) array detector, it is necessary to acquire many partial spectra, each at a different angular position of the grating, and splice the partial spectra into a single extended spectrum. The splicing procedure exposes instrument dependent artifacts. It is demonstrated that by taking a spectrum of a reference irradiance source and making spectral correction, the artifacts exposed by the splicing are removed from the analyte spectrum. This is because the irradiance reference spectrum contains the same artifacts as the analyte spectrum. The artifacts exposed by the splicing depend on the wavelength of the splice; therefore it is important to measure the irradiance reference spectrum for the same range of wavelengths used to measure the spectrum of the analyte solution. In other words, there is no general spectral correction factor which is applicable to spectra taken for different range of wavelengths. The wavelength calibration is also carried out by splicing many partial spectra from a source like a krypton lamp. However the wavelength assignments are not sensitive to the splicing procedure and the same wavelength calibration can be used for spectra acquired over different extended wavelength ranges. The wavelength calibration checks the validity of the setting of the grating angular position, and the assignment of wavelengths to individual pixels on the CCD array detector. The procedure is illustrated by measuring the spectrum of an orange glass and the spectrum of a suspension of microalgae.     

Fabrication of Metallic Magnetic Calorimeter X-ray Detector Arrays

Microcalorimeters with metallic magnetic sensors show great promise for use in astronomical X-ray spectroscopy. We describe the design and fabrication of a lithographically patterned magnetic microcalorimeter. A paramagnetic AuEr film is sputter-deposited as the sensor, which is coupled to a low noise SQUID via a meander superconducting pickup loop used as an inductor. This inductor also provides the magnetic field bias to the sensor. The AuEr film is deposited over this meander such that the field created by a large current flowing in the loop magnetizes the sensor material. The use of thin film techniques in the fabrication of these magnetic sensors not only allows strong magnetic coupling between the sensor and the inductor, it also is scalable for array fabrication.      

Development of Multilayer Readout Wiring TES Calorimeter for Future X-ray Missions

We have fabricated multilayer readout wiring transition edge sensors (TES), which enable us to realize both large effective area and high-energy resolution for future X-ray astrophysical missions, such as diffuse intergalactic oxygen surveyor. By sandwiching a SiO \(_2\) insulation layer between Al superconducting signal and return lines, self/mutual inductances and self fielding of bias leads are expected to be reduced. We fabricated \(4\times 4\) and \(20\times 20\) TES array on the multilayer wiring and tested their performance. Under the low temperature condition, several pixels in the TES array showed sharp superconducting transitions at around \(\sim \) 300 mK. We also succeeded in detecting X-ray signals from the \(4\times 4\) TES, contrary to the previous results of \(20\times 20\) TES. We further investigated the reasons for the differences between the \(4\times 4\) TES and the \(20\times 20\) TES, and present future plans for improving the multilayer TES array fabrication.     

Near-Field Gain Correction for Transmission between Horn Antennas

When the gain of a horn antenna is to be measured from the power transmission loss between it and a standard horn, the Friis transmission formula must be corrected if the horn separation is not considerably greater than 2d2/?. Expressions for the correction between a pyramidal horn and a conical horn, and between dissimilar pyramidal horns, are presented with sample results. A method of applying these corrections to minimize the errors in the horn gain measurements is described.     

电感耦合等离子体发射光谱的光谱仪

<正> The spectrometer is a very important integrant of an ICP-AES system. In this talk, the general architecture and requirements of the spectrometer for ICP-AES, the grating, the simultaneous multichannel and sequential spectrometers, etc., will be reviewed.     

The X-ray Quantum Calorimeter Sounding Rocket Experiment: Improvements for the Next Flight

We have developed a new calorimeter array to increase our collecting area by a factor of four. The 6×6 pixel device has a total area of 144 mm², making it one of the largest X-ray microcalorimeter arrays yet constructed. A relatively thin high-z absorber consisting of a 0.7 μm HgTe layer supported on 15 μm high-purity silicon provides good efficiency up to photon energies of 1.5 keV. The heat capacity of this composite is low enough to obtain an energy resolution of ∼6 eV FWHM on the 2 mm×2 mm pixels when operated at a base temperature of 50 mK. The infrared blocking filters have also been improved. Room temperature radiation must be attenuated by about 9 orders of magnitude between 2 μm and 2 cm to avoid having photon shot noise dominate the detectornoise. Accomplishing this while maintaining a high transmission for very soft X-rays that can penetrate only a few μg cm⁻² is a problem common to all soft X-ray calorimeters that observe external targets. We are constructing monolithic silicon two-layer support meshes with a 350 μm pitch front layer on a 5 mm pitch backing layer. These are 98% open and have >95% effective transmission over a 60° field of view, while providing robust support for 38 mm diameter filters consisting of 20 nm of aluminum on 50 nm of polyimide. Five of these filters in series provide the necessary infrared attenuation. Integral deicing heaters are ion implanted in the fine mesh to remove contamination when necessary.      

DC SQUID Spectrometers for NMR

We report experiments in which we have used DC SQUIDs in pulsed NMR spectrometers to observe directly the free precession of nuclear spins. A broadband spectrometer, which operates in flux-locked loop mode with a bandwidth of 3.4 MHz using a SQUID with additional positive feedback and an untuned superconducting input circuit, has been used to observe NMR signals from platinum powder at frequencies of 38, 65, 85, 240 and 513 kHz. The performance is compared with a second system in which a DC SQUID is operated open loop as a small signal rf amplifier with a series tank input circuit tuned at 1 MHz.     

外推法天线增益测量的阻抗失配修正及其不确定度评定

基于信号流图分析法建立了全端口阻抗失配模型,推导出天线增益的阻抗失配修正公式,结合各端口散射参数实测值可计算出阻抗失配修正值。此外,还提出了一种基于蒙特卡罗法的阻抗失配修正不确定度及其概率分布特性评定方法,为科学、系统地评定外推法增益测量不确定度提供有效方法。     

离子迁移谱检测仪信号处理方法研究

离子迁移谱（IMs）检测仪是对化学毒剂、有毒有害气体等化学物质进行痕量检测和分析的一种有效的快速现场检测仪器．介绍了离子迁移谱检测仪的组成结构和工作原理,先后讨论了几种信号处理方法,并对含噪IMS信号进行了处理．结果表明,数据平均、平滑、数字滤波有效消除了IMS信号中的噪声,本底扣除消除了信号基线的非线性特征,求导数法能准确地确定谱峰的峰位,确定了以约化离子迁移率为特征值的识别方法．这为实现IMS信号的准确识别奠定了基础．     

Bakelite RPCs for Digital Hadron Calorimeter

This paper presents the test results of Bakelite RPCs using readout pads with an area of 1 cm×1 cm and 1-bit resolution per pad (binary readout). The results include noise rate, detection efficiency and pad multiplicity as well as comparisons of different surface treatments for Bakelite plates. Pad multiplicity’s dependence on surface resistivity at the readout side is also reported. This study shows Bakelite RPCs can be used as the active elements of digital hadron calorimeter.     

Design, Fabrication, and Multiplexing of Magnetic Calorimeter X-ray Detectors with High-Efficiency SQUID Readout

Metallic magnetic calorimeters, where deposited energy is detected by measuring a temperature-dependent magnetization with a low-noise SQUID, remain a promising potential route to X-ray spectrometers with energy resolution approaching 1 eV. In this paper we describe our recent work toward array-compatible, high-resolution MMCs fabricated entirely using thin-film techniques. We describe a meander-style pickup loop designed for good coupling to high-efficiency, low noise SQUIDs, as well as considering various routes to a thin-film paramagnetic sensor. We also briefly overview the most promising technology for multiplexing arrays of non-dissipative metallic magnetic calorimeters.      

Information Signals and Structural Layouts for Atomic-Absorption Spectrometers

Functions of information signals and structural layouts of atomic-absorption spectrometers with correction of interfering factors, including changes in the parameters of instrument units, the media being analyzed, and surrounding conditions are considered.__________Translated from Izmeritel’naya Tekhnika, No. 4, pp. 62–66, April, 2005.     

双读出量能器用闪烁晶体研究进展

双读出量能器是一种全新设计的高能粒子探测装置, 它能同时测量到Cherenkov光和闪烁光, 因而能更全面地获得高能粒子的信息。目前, 双读出量能器主要有三种设计方式: (1)采用石英纤维产生Cherenkov光, 塑料闪烁纤维生成闪烁光; (2)分别以未掺杂的晶体纤维作为Cherenkov辐射体、Ce掺杂的同种晶体纤维作为闪烁体; (3)采用同种闪烁晶体有效分离Cherenkov光和闪烁光。第三种设计可以消除取样涨落、提高量能器的分辨率, 因而备受关注。本文基于第三种设计方式探讨了钨酸铅(PbWO₄)、锗酸铋(Bi₄Ge₃O₁₂)、硅酸铋(Bi₄Si₃O₁₂)和镥铝石榴石(Lu₃Al₅O₁₂)四种。闪烁晶体在双读出量能器方面的研究进展和可能的应用。Pr掺杂PWO晶体以及硅酸铋晶体都有可能用于双读出量能器, 而后者由于吸收边比锗酸铋更短, 更易于分离Cherenkov光和闪烁光, 在双读出量能器应用方面显示出明显的优势。稀土离子掺杂有望进一步提高硅酸铋晶体的性能, 开发出更适合双读出应用的闪烁材料。     

自适应时间常数的时域高通滤波校正算法

针对时域高通滤波非均匀性校正算法中存在只对偏移响应系数进行校正、难以选取合适的时间常数以及滤波后图像细节不清晰等问题,本文通过分析时间常数对算法校正效果的影响,提出了一种改进的时域高通滤波非均匀性校正算法。首先采用离线采集的非均匀性噪声底图对红外焦平面阵列的原始输出图像进行预处理,去除部分固定模式噪声,保证了增益的均匀性;然后通过运动检测环节判断场景运动是否充分,根据运动程度自适应选取时间常数构造低通滤波器;最后运用高频提升滤波达到提升红外图像整体的亮度和增强目标细节的效果。对真实的红外视频图像实验表明,通过自适应选取时间常数有效地抑制了目标退化和伪像现象,且算法的收敛速度快,校正后图像细节清晰,有利于工程实时应用。     

Improvements in a Calorimeter for High-Power CW Lasers

Measurement certainty with the BB series of electrically calibrated calorimeters for high-energy lasers has been enhanced by the addition of monitors for energy backscattered from the meter and for energy missing the entrance aperture (overspill). The performance and design features of the recently constructed BB2 meter are compared with the previously described BB1 meter. Direct intercomparison shows the agreement between meters to be 1 percent.     

自动量热仪测量结果不确定度评定

本文详细介绍了自动量热仪热值误差测量结果的不确定度评定方法。