A photon counting dynamic digital lock-in amplifier for background suppression in glow discharge atomic emission spectrometry

1996-01-15
Gokmen, A
Ulgen, A
Yalcin, S
A photon counting dynamic digital lock-in amplifier, (PC-DDLIA), has been developed for the suppression of Ar lines in glow discharge lamp atomic emission spectrometry, (GDL-AES). The experimental set-up consists of a Grimm-type GDL, a prism-type scanning monochromator, photon counting electronics, an Apple Ile computer with an interface card and a computer controllable high voltage power supply. The photon counting electronics are designed to convert the photon pulses to logic pulses. A discriminator is used to reject pulses below a threshold level. The high voltage power supply is modulated with a square waveform generated from DAC and photon pulses are counted synchronously by the timer/counter chip, versatile interface adaptor (VIA-6522) on the interface card of computer. The data are analyzed in two steps. In the ''learn mode'', the GDL is modulated with a square waveform between 370 and 670 V and two spectra consisting of only Ar lines are obtained in a spectral window between 287.1 and 290.0 nm. A new modulation waveform is computed from these spectra which yields two overlapped spectra when the PC-DDLIA is scanned over the same spectral window. In the ''analysis mode'' of data acquisition, a target material with the analyte element(s) in it is used and the spectrometer is scanned with a dynamically varying rectangular waveform over the same spectral window. The net spectrum consists of pure atomic lines free from any Ar lines. The detection limit for the determination of Si (288.2 nm) in the presence of interfering hr lines (288.1 and 288.4 nm) is found to be 0.083%, whereas suppression of Ar lines over the same spectral window lowers the detection limit to 0.013%.
SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY

Suggestions

A readout circuit for QWIP infrared detector arrays using current mirroring integration
Tepegoz, M; Akın, Tayfun (2003-09-18)
This paper reports a current mirroring integration (CMI) CMOS readout circuit for high-resolution Quantum Well Infrared Photodetectors (QWIPs). The circuit uses a feedback structure with current mirrors to provide stable bias voltage across the photodetectors, which can be adjusted between 0 V and 3.5V. The photodetector current is mirrored to an integration capacitor which can be placed outside of the unit pixel, reducing the pixel area and allowing to integrate the current on larger capacitances for large...
A MEMS Based Lens Microscanner for Resolution Enhancement of Infrared Imaging Systems
Sozak, Ahmet; Simsek, Ertug; Azgın, Kıvanç (2019-01-01)
The aim of this study is to demonstrate a Micro Electro Mechanical Systems (MEMS) based in-plane (x and y axes) lens scanner to improve the resolution of Long Wave Infrared Optical Systems (8-12 mu m wavelength). The proposed actuator consists of a 2 axis decoupled stage and has 4 separate V-Shaped (Chevron) thermal actuators which provide sufficient force and displacement to position the lens within required time. Miniaturization of lens has been achieved by using an aspherical surface and optimization of ...
BACKGROUND SUPPRESSION OF AR LINES IN GLOW-DISCHARGE ATOMIC EMISSION-SPECTROMETRY BY A LOCK-IN AMPLIFIER AND KALMAN FILTER DECONVOLUTION
ULGEN, A; DOGAN, M; Gökmen, Ali; YALCIN, S (1993-01-01)
The Ar spectral lines are suppressed in Grimm-type glow discharge lamp atomic emission spectrometry (GDL-AES) by a double voltage modulation technique. The GDL is modulated between two voltage levels, typically 400 and 700 V. At the lower voltage level mainly Ar emission contributes whereas at the higher voltage level both Ar and atoms sputtered from the cathode contribute to the emission. The Ar emission spectrum at the lower voltage level is multiplied by a constant factor to scale it up to the same level...
A low-cost uncooled infrared microbolometer detector in standard CMOS technology
Tezcan, DS; Eminoglu, S; Akın, Tayfun (Institute of Electrical and Electronics Engineers (IEEE), 2003-02-01)
This paper reports the development of a low-cost uncooled infrared microbolometer detector using a commercial 0.8 mum CMOS process, where the CMOS n-well layer is used as the infrared sensitive material. The n-well is suspended by front-end bulk-micromachining of the fabricated CMOS dies using electrochemical etch-stop technique in TMAH. Since this approach does not require any lithography or infrared sensitive material deposition after CMOS fabrication, the detector cost is almost equal to the CMOS chip co...
A Self-Powered and Efficient Rectifier for Electromagnetic Energy Harvesters
Ulusan, Hasan; Zorlu, Ozge; Muhtaroglu, Ali; Külah, Haluk (2014-11-05)
This paper presents an interface circuit for efficient rectification of voltages from electromagnetic (EM) energy harvesters operating with very low vibration frequencies. The interface utilizes a dual-rail AC/DC doubler which benefits from the full cycle of the input AC voltage, and minimizes the forward bias voltage drop with an active diode structure. The active diodes are powered through an AC/DC quadrupler with diode connected (passive) transistors. The interface system has been validated to drive 22 m...
Citation Formats
A. Gokmen, A. Ulgen, and S. Yalcin, “A photon counting dynamic digital lock-in amplifier for background suppression in glow discharge atomic emission spectrometry,” SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY, pp. 97–108, 1996, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/66915.