Reader System Research Articles

A ROBUST 900 MHz RFID READER CHIP WITH RC-CALIBRATION

A fully integrated RFID reader chip targeted to operate in the frequency range of 860 MHz to 960 MHz is designed, simulated and fabricated. To reduce the chip performance degradation due to process and temperature variation, resistor and capacitor calibration is adopted. The output codes of resistor calibration are used to adjust main circuit blocks' biasing current while the output codes of capacitor calibration are used to fine tune filter bandwidth and Digital-to-analog converter (DAC) conversion accuracy. Dual-tuned magnetic coupled LC tanks are also introduced in our VCO design to improve phase noise performance and extend tuning range, so as to enhance the robustness of the proposed RFID reader system. The reader is implemented with a low cost 90 nm standard CMOS process and has a chip area of 3.1 mm by 3.3 mm. The chip is packaged with QFN48 and tested on PCB. The proposed RFID reader consumes 90 mW of power and has robust performance against temperature, voltage supply and process variation. The merits of the chip make it ideal for various application scenarios.

The Research and Design of Card Reader Based on RFID

This paper designed a RFID-based card reader system, which is based on Cortex-M3 LM3S9B90 chip controller, using MRC531 as the base station chip and Mifare1S50 as card read-write. The system realizes the identification and data reading and writing of Mifare1S50 card with a frequency of 13.56MHz, while it can also communicate with the host computer conveniently. The communications use open-source TCP / IP protocol stack LWIP.

A Robust Baseband Demodulator for ISO 18000-6C RFID Reader Systems

One key challenge for ultra-high frequency (UHF) radio-frequency identification (RFID) reader design is to demodulate the weak tag response signal which tends to be easily distorted and has considerable frequency deviations. In this paper, a baseband demodulator based on a matched filter (MF) is proposed to enhance the reliability of signal processing for the EPCglobal Class-1 Generation-2 (Gen2) RFID reader systems. The proposed demodulator is very robust against strong signal distortions and large frequency deviations happening on the received backscattered signal from a passive RFID tag. The validity and usefulness is demonstrated by both computer simulations and implementation experiments.

MO‐F‐213CD‐04: Characterization of Optically Stimulated Luminescence Detectors for Organ Dose Phantom Measurement in Diagnostic Radiology

Purpose: To evaluate the feasibility and accuracy of using aluminum oxide doped with carbon (Al2O3:C) and beryllium oxide (BeO) optically stimulated luminescence (OSL) detectors for the purpose of measuring organ dose in a phantom for diagnostic radiology. Methods: The energy response of each type of detector as a function of kVp and in‐phantom depth was determined using blocks of Polymethyl methacrylate (PMMA) and an ionization chamber (0.4 cm3). The Al2O3:C detectors used in this study were cut from LuxelTM tape into 4 mm diameter circles of thickness 0.3 mm. The BeO detectors used in this study are ∼4.7 mm x ∼4.7 mm x 0.5 mm chips. Clinical irradiations were performed using a radiographic unit. The BeO signal was read using a Riso/, TL/OSL‐DA‐15 automated reader and the Al2O3:C signal was read using a custom‐built light emitting diode (LED)‐based reader system. The results were compared to those obtained from LiF:Mg,Ti thermoluminescence detectors (TLD). Results: The energy‐dependent response as a function of depth within the phantom for BeO and Al2O3:C were found to be < 8% and < 10%, respectively. For comparison, the TLDs were found to have an energy‐dependent response of ∼8%. The OSL detectors both offered reproducibility better than 5%. Conclusions: The proposed method of using BeO and Al2O3:C OSL detectors to perform in‐phantom measurements has a comparable in‐phantom energy response to that of TLD's and shows improved reproducibility of the measurements when compared to TLD's. Given the flexibility and accuracy of OSL detectors for various readout techniques, OSL detectors have a great potential to be used in clinical organ dose measurement for diagnostic x‐ray exams.

A CCD-Based Reader Combined Quantum Dots-Labeled Lateral Flow Strips for Ultrasensitive Quantitative Detection of Anti-HBs Antibody

Herein we reported a CCD-based reader combined quantum dots-labeled lateral flow strips for ultrasensitive quantitative detection of anti-HBs antibody. The CdTe quantum dots were prepared, then were used to label Hepatitis B Virus surface antigen, and then were fabricated into lateral flow strips. The as-prepared lateral flow strips were used to test different concentration of anti-HBV surface antibodies. The CCD-based reader was designed and fabricated, the quantitative analysis software was compiled, and resultant CCD-based reader system was used for quantitative analysis of examined anti-HBs antibodies on the strips. Results showed that the quantum dots-labeled lateral flow strips could detect the anti-HBs antibody with the limitation concentration of 200 pg/mL, the CCD-based reader system could detect anti-HBs antibody with the sensitivity of 2 pg/mL. In conclusion, the prepared CCD-based reader combined quantum dots-labeled lateral flow strips can be used for quantitative detection of anti-HBs antibody in sera with the sensitivity of 2 pg/mL, and has great potential in applications such as ultrasensitive detection of HBV antigens or antibodies, and other tumor biomarkers in near future.

Rapid on‐site determination of melamine in raw milk by an immunochromatographic strip

SummaryA rapid and simple method was established based on gold nanoparticle‐labelled monoclonal antibody probes for the detection of melamine pollution in raw milk. The conditions for conjugation between the antibody and gold nanoparticles were optimised (pH 8.0, antibody concentration 5 μg mL−1). It gives a single proportional to melamine concentration with a performance time of only 3 min. A practical calibration curve was established with a reader system with limit of detection calculated as 4.47 and 8.34 μg L−1 with naked eyes. Three structural analogues, atrazine, desethyl‐desisopropyl‐atrazine and cyromazine, were used to test the specificity of the immunochromatographic strip, and small colour changes on the strip test line were found even at the 500 ng mL−1 spiked level. Fifty raw milk samples were detected with this strip method, and the resulting data coincided well with results from gas chromatography tandem mass spectrometry. The above‐mentioned results showed that this test strip can be used for melamine screening in the daily monitoring of milk.

Kinetics of Advanced Glycation End Products Formation on Bovine Serum Albumin with Various Reducing Sugars and Dicarbonyl Compounds in Equimolar Ratios

Reducing sugars and reactive dicarbonyl compounds play a major role in glycation of proteins in vivo. Glycation of proteins is the first step in of a nonenzymatic reaction, resulting in advanced glycation end products (AGEs). AGEs can inactivate proteins or modify their biological activities. Therefore, it is important to understand the mechanism of AGE formation. Here, we systematically analyzed the kinetics of AGE formation in vitro by fluorescence and absorption measurements utilizing a microplate reader system and bovine serum albumin (BSA) as a model protein. Comparing different concentrations of BSA, we applied various reducing sugars and reactive dicarbonyl compounds as AGE-inducing agents at different concentrations. In summary, this experimental setup enabled us to measure the kinetics of AGE formation in an efficient and defined way.

선량 판독용 OSL 측정장치의 개발

Design and performance test results of a newly developed optically stimulated luminescence (OSL) measurement system are presented in this paper. Generally, different types of optical filters are used in OSL reader system to minimize the interference of the stimulation light in the OSL signal. For optically stimulation of , we have arrived at an optimal combination of the filters, i.e., GG420 filter for filtering the stimulating light source, and a combined UG11 and BG39 filter at the detecting window (PMT). By using a high luminance blue LED (Luxeon V), sufficient luminous intensity could be obtained for optically stimulation. By using various control boards, the OSL reader device was successfully interfaced with a personal computer. A software was developed to deliver required commands to operate the OSL reader by using the LabView program (National Instruments, Inc.). In order to evaluate the reliability and the reproducibility of newly designed-OSL reader. Performance testing of the OSL reader was carried out for OSL efficiency, OSL decay curve and signal to noise ratio of the standard OSL material. It was found to be comparable with that of commercial Riso reader system.

A Passive Radio-Frequency pH-Sensing Tag for Wireless Food-Quality Monitoring

We present a new method, suitable for food quality management by wirelessly monitoring pH level changes in food with a flexible pH sensor embedded in a batteryless radio-frequency (RF) transponder. The wireless sensor tag includes a flexible pH sensor based on miniature iridium oxide (IrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> ) and silver chloride (AgCl) sensing electrodes integrated on a deformable substrate, and batteryless wireless communication circuitry. The sensor tag and reader system is designed to achieve convenient, long-term, and on-demand wireless in situ monitoring of food quality, especially for large-quantity applications and continuous monitoring from place of production to retail stores. Low-cost IrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> sol-gel fabrication process was applied on polymeric substrates to form the flexible sensing films, and a sensitivity of -49.7 mV/pH was achieved. Inducting coupling provides electromagnetic energy from the reader to drive the transponder circuits that retransmit the sensor-data modulated signals back to the reader. The electrochemical potential created by the IrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> /AgCl sensing electrodes is converted to a modulated frequency and the system achieves a sensitivity of 633 Hz/pH. The wireless pH sensing system was tested for in situ monitoring of the spoilage processes in fish meats continuously for over 18 h. The feasibility of wirelessly monitoring pH values in fish meats that could be used to identify spoilage remotely has been demonstrated.

WIDEBAND CIRCULARLY POLARIZED UHF RFID READER ANTENNA WITH HIGH GAIN AND WIDE AXIAL RATIO BEAMWIDTHS

A broadband circularly polarized patch antenna with high gain and wide axial ratio beamwidths is proposed for ultra-high- frequency (UHF) RF identiflcation (RFID) applications in this paper. The antenna is composed of a square patch, a feed network printed on the bottom side of the substrates and an antenna radome. The CP radiation of the proposed antenna is excited by four cylinder probes which transmit four signals that have equal amplitude with quadrature phase difierence (0 - , 90 - , 180 - , and 270 - ) generated from the feed network. To obtain an optimum peak gain and a broad CP bandwidth, 100› isolation resistor is omitted in the feed network for obtaining high radiation e-ciency, and the efiects of varying the feed positions and dimensions of the various parameters on the antenna performances are respectively investigated. Simulation results are compared with the measurements, and a good agreement is obtained. The measured results show that the proposed antenna can provide broad impendence bandwidth of 19.7% (815{993MHz) (re∞ection coe-cient less than i15dB), a maximum gain of 9.65dBi, and a 3-dB axial ratio (AR) bandwidth of about 11% (860{960MHz). The results indicate that the proposed antenna is an excellent candidate for UHF RFID reader system. At last, read performance of the proposed antenna array in RFID systems is presented, which verify the superior features of the proposed antenna in practical RFID system applications.

ChemInform Abstract: Present Status of Radiochromic Techniques for Nuclear Radiation Measurements

AbstractReview: 17 refs.

Research on Long Distance Radio Frequency Identification System of Toolholder

Considering the difficulty in identifying the tool system in the process of tool management, this paper proposes a design of toolholder identification system which is capable of storing all tool date using commercially available radio frequency identification (RFID) tags. The system is composed of radio frequency electronic tags, ultra high frequency reader and computer identification system. The paper gives the hardware and software design of toolholder identification system.

Automatic Antenna Tuning Unit to Improve RFID System Performance

Systems for radio-frequency identification (RFID) realize a bidirectional wireless communication between a reader device and cheap passive tags (e.g., an RFID chip with an antenna printed on badges for access-control systems) in the near field of an antenna. This paper deals with the automatic and fast tuning of the resonant reader antennas in the widely used 13.56-MHz frequency band, resulting in a performance improvement and an increased read/write range. A novel RFID reader system is proposed with a tuning transformer for the automatic adjustment of the resonant circuit center frequency. This is achieved by shifting the magnetic operating point (i.e., the biasing direct-current (dc) magnetization) of a Ni-Zn ferrite transformer by means of an additional dc winding. The operation principle and the performance potential of this device are demonstrated by measurements on a prototypical RFID system.

Thermal behaviour of a LiF crystal mounted in a TLD card and heated by jet impingement

Abstract A numerical model is developed to predict the actual temperature profile evolution in a crystal contained in a TLD card that is used in advanced gas heating TLD reader systems. The flow field above the detector and the resulting heat transfer to and within the crystal are obtained directly, and no empirical constants or adjustment parameters are used. It is found that the typical time lag between the crystal temperature and the jet temperature is about 5 s, for the heating rate of 25 K/s. The calculated temperature profile is substituted into a first-order kinetic model equation (Randall–Wilkins) to obtain the glow curve, and the results are compared to experimental findings. It is shown that the location of the peaks resulting from the calculated temperature profile overlaps those of the experimental results. Thus, calibration is conducted only to match the intensity of the TL peaks.

Caveats and limitations of plate reader-based high-throughput kinetic measurements of intracellular calcium levels

Calcium plays a crucial role in virtually all cellular processes, including neurotransmission. The intracellular Ca 2+ concentration ([Ca 2+] i) is therefore an important readout in neurotoxicological and neuropharmacological studies. Consequently, there is an increasing demand for high-throughput measurements of [Ca 2+] i, e.g. using multi-well microplate readers, in hazard characterization, human risk assessment and drug development. However, changes in [Ca 2+] i are highly dynamic, thereby creating challenges for high-throughput measurements. Nonetheless, several protocols are now available for real-time kinetic measurement of [Ca 2+] i in plate reader systems, though the results of such plate reader-based measurements have been questioned. In view of the increasing use of plate reader systems for measurements of [Ca 2+] i a careful evaluation of current technologies is warranted. We therefore performed an extensive set of experiments, using two cell lines (PC12 and B35) and two fluorescent calcium-sensitive dyes (Fluo-4 and Fura-2), for comparison of a linear plate reader system with single cell fluorescence microscopy. Our data demonstrate that the use of plate reader systems for high-throughput real-time kinetic measurements of [Ca 2+] i is associated with many pitfalls and limitations, including erroneous sustained increases in fluorescence, limited sensitivity and lack of single cell resolution. Additionally, our data demonstrate that probenecid, which is often used to prevent dye leakage, effectively inhibits the depolarization-evoked increase in [Ca 2+] i. Overall, the data indicate that the use of current plate reader-based strategies for high-throughput real-time kinetic measurements of [Ca 2+] i is associated with caveats and limitations that require further investigation.

High-Throughput Measurement and Classification of Organic P in Environmental Samples

Many types of organic phosphorus (P) molecules exist in environmental samples1. Traditional P measurements do not detect these organic P compounds since they do not react with colorimetric reagents2,3. Enzymatic hydrolysis (EH) is an emerging method for accurately characterizing organic P forms in environmental samples4,5. This method is only trumped in accuracy by Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy (31P-NMR) -a method that is expensive and requires specialized technical training6. We have adapted an enzymatic hydrolysis method capable of measuring three classes of phosphorus (monoester P, diester P and inorganic P) to a microplate reader system7. This method provides researchers with a fast, accurate, affordable and user-friendly means to measure P species in soils, sediments, manures and, if concentrated, aquatic samples. This is the only high-throughput method for measuring the forms and enzyme-lability of organic P that can be performed in a standard laboratory. The resulting data provides insight to scientists studying system nutrient content and eutrophication potential.

SU‐E‐T‐268: The Evaluation of Dosimetric Characteristic of Radiophotoluminescent Glass Dosimeter According to Reading Methods of Reader

Purpose: Statistical checks of system parameters and follow up of readerˈs behavior will give a broader understanding into the operational characteristics of the reader and may help for proper maintenance of the system. The purpose of this study is to suggest effective use of reading methods for reducing the uncertainty in dose measurements through the investigation of characteristics of GD‐based reader system. Methods: To evaluate the characteristics of readerˈs, we performed measurement such as reproducibility of repeated reading, readout variation according to the number of GD loading on readout magazine, and deviation depending on each magazine position. To evaluate dose reproducibility we made a try to do repeated reading up to 200 times for each 15 GDs. Also, to evaluate readout variation characteristic, 80 GDs are irradiated one by one under the same irradiation conditions. Reading process was measured with 4 different cases. Lastly, to measure the deviation magazine position, we examine the readout values according to each loading position.Results: According to measurement result, reproducibility shows 1.3% lower measurement from total 200 times. Readout sensitivity of GD on magazine values is normalized to 1st position response. 1 to 5th position measured 1.015, also 1 to 10th position examined 1.022, and 1 to 20th position presented 1.035. Lastly, at all position except for 20th position of magazine, response is tend to increase gradually. It was overestimated on 2.0% of average rather than response at reference position (first position). Conclusions: According to the result, we should put each GD in consecutive order from 1st space of magazine to get accuracy value of dose and it is recommended that reading process should be performed the only first position of magazine with regard to absolute dosimetry.This work was supported by Nuclear Research &amp; Development Program of the National Research Foundation of Korea(NRF) grant funded by the Korean government(MEST).

WE‐C‐110‐07: Estimation of CT Radiation Profile Width Using an LED‐Based Optically Stimulated Luminescence System

Purpose: To evaluate the feasibility and accuracy of an LED‐based Optically Stimulated Luminescence (OSL) system for measuring computed tomography (CT) radiation profile width. Methods: The OSL detector strips used consisted of a layer of Al2O3 :C powder incorporated into a plastic tape. The strips were 150 mm long with a width of 4–5 mm and thickness of 0.3 mm. The 64‐slice CT dose profiles were measured by irradiating the OSL strips both free‐in‐air and inside the PMMA head and body phantoms. Three separate OSL strip measurements were performed for each scan condition. The exposed strips were then read out using a custom built LED‐based reader system, which operated for 150 mm in 0.25 mm steps, providing 600 data points along the OSL strip in 60 sec. The width of the CT radiation profiles was determined from the full width half maximum (FWHM) at different nominal beam collimations. The results were compared to those obtained from digitized film profiles and ionization chamber point measurements (0.3 cc ionization chamber). Results: By comparing the FWHM values of OSL and digitized film measured free‐in‐air, the system accuracy was verified with results &lt; ± 2.2% for nominal beam widths of 5, 10, 20 and 40 mm. The relative OSL response as a function of phantom positions was verified by comparing the FWHM values in phantom measurements using OSL and ionization chamber. The results agreed well within 7.6%. Conclusions: The proposed method of using an LED‐based OSL system to determine the FWHM of the CT radiation profile has a high accuracy and shows good agreement with the conventional film measurements and the more advanced point‐dose methodology proposed by TG 111. Combined with the simple calibration, it gives this work a great potential to be used in routine clinical quality assurance check.

WE‐G‐110‐09: Evaluation of Different Techniques for CT Radiation Profile Measurement

Purpose: To demonstrate a procedure for using a Konica Minolta computed radiography (CR) system for the measurement of computed tomography (CT) radiation profiles and to compare this method with conventional and radiochromic film measurements. Methods: The exposure and processing conditions of a Konica Minolta CR reader system were characterized to establish the relationship between exposure in the imaging plate (IP) and pixel value. A 6 cc ionization chamber was exposed at the isocenter of a CT scanner using 80 kVp, 0.4s with various mA settings. CR images were processed in fix modes with various combinations of G and S values, establishing exposure and pixel value relationships. Optimal mA settings and processing parameters were selected to avoid the overexposure of the IP. The radiation profiles were collected using different collimation settings (40, 20, 10 and 5 mm) at 10 and 20 mA, respectively. The peak pixel value measured from the 10 mA profile was used to identify the location of 50% of maximal exposure in the 20 mA profile. The FWHM of the dose profile at different collimation beam widths can then be determined. The results were compared to those obtained from digitized conventional and radiochromic film profiles. Results: The optimal exposure (80 kVp, 0.4s, large body filter, 10 and 20 mA) and processing settings (fix mode with S = 5 and G = 1.81) were determined for CT radiation profile measurement. The FWHM results measured using this method agreed well within ±10% when compared to the conventional and radiochromic film results. Conclusions: The FWHM of CT radiation profiles can be accurately measured using a Konica Minolta CR system, when appropriate exposure technique and processing parameters are used. It has been proven to be a convenient and cost‐effective method for routine clinical quality assurance checks.

SU‐C‐224‐11: Investigating the Effects of Using Several Calibration Conditions on the Measurement Accuracy of Plastic Scintillation Detectors

Purpose: To investigate the effects of using several conditions (employing assorted radiation field sizes, doses, and depths in water) for the calibration of a plastic scintillation detector (PSD) on measurement accuracy. Methods: The detector system comprised one PSD and a charge‐coupled device (CCD) camera‐based reader system designed to implement the chromatic removal method for discriminating Cerenkov light from scintillation signal. PSD systems of this type are typically calibrated using only two calibration conditions. In this study, we constructed twelve calibration conditions using field sizes of 5×5, 10×10, 20×20, and 30×30 cm2; doses of 10 and 100 cGy; and depths of 2 and 10 cm, with the PSD centered in a water phantom for 60Co irradiation. We used every combination of two or more conditions (up to twelve) to produce 4083 distinct sets of calibration factors via a combinatorial computer algorithm. We tested all calibrations against data taken using a clinical linear accelerator with the PSD placed at water‐equivalent depths of dose maximum and 6.6 cm for 6 MV (setups ‘A’ and ‘B’, respectively) and 18 MV (setups ‘C’ and ‘D’, respectively) photon beams. Results: The most accurate calibration resulted from a combination of four conditions using both depths, field sizes of 10×10 and 30×30 cm2, but all using 10 cGy doses. For setups A, B, C, and D the PSD‐measured dose differed from the known dose by 0.5%, 0.9%, 0.3%, and 0.3% respectively. However, six hundred of the calibrations resulted in differences of &lt;1% between PSD and known doses delivered by the linac across the four test setups Conclusions: This study suggests that the accurate calibration of PSDs is flexible with respect to the number of conditions used, though certain condition combinations should be avoided due to their considerable inadequacy in satisfying the requirements of the chromatic removal method.This work was supported in part by the National Cancer Institute through a T32 grant (CA119930‐04) and an R01 grant (CA120198‐01A2).