Alpha Analyzer Access Video

Deep-Sea Gas Analyzers

2009-10-07T16:41:00.000-07:00

The Deep-Sea Gas Analyzer provides an accurate measurement of a variety of gases at depths of up to 2500 meters. The instrument employs a membrane gas extractor and is capable of measuring virtually any gas in LGR’s catalog, including CH4, CO2, and various stable isotopomers. Self-sustained, remote operation is possible using the internal battery, gas handling system, and data storage. Possible applications include carbon sequestration in ocean waters, methane-hydrate studies, and hydrothermal-vent effluent analysis.
As described in the Theory Section (on www.lgrinc.com), the measurement strategy is based on high-resolution direct-absorption spectroscopy. As a result, the instrument is self-calibrating and provides an absolute, accurate gas concentration without reference standards. An internal computer can store data practically indefinitely for applications requiring unattended long-term standalone operation. These analyzers can also send real-time data to a data logger through analog, digital (RS232), and Ethernet outputs.

Brimrose NIR Analyzer

2009-09-23T17:28:00.000-07:00

A new series of miniature near-infrared (NIR) spectrometers is said to offer a cost-effective tool for inspecting incoming raw materials and product quality control. Compact, battery-powered Model 5030 ATOF-NIR Portable Analyzer from Brimrose Corp. of America, Baltimore, allows laboratory tests to be performed anywhere in a plant environment. The instrument, which sells for $28,000 (compared with $40,000 for larger units), is reportedly insensitive to ambient light, vibration, dust, and dirt. Its design allows for quick switchover from solids to liquids, and results appear instantly on its LCD. Applications include material identification or measurement of moisture content and active-ingredient levels. Once the instrument is calibrated, it reportedly can be used by an inexperienced operator.

Alpha Analysis

2009-06-05T03:13:00.001-07:00

Our alpha analysis is deteriorating rapidly even though the major indexes are doing a relatively good job of minimizing extensive losses so far. Of the 1,716 issues analyzed this morning for alpha generation, only 346 are “buy” recommended, which is our lowest level since August 2nd. Even more significant is that nearly 50% of the securities are “short/sell” recommended, which illustrates the broad-based weakness developing.

The S&P 100 (OEF 8/4/06) remains the only “buy” recommended major market derivative after Friday’s close. The Russell 2000 (IWM) and other small-cap derivatives had been among our highest ranked over the last few weeks for beta exposure, yet they were downgraded to “sell” status this morning. However, I’d be fairly surprised if the small-cap indexes retain a “sell” recommendation for more than a week or two.

Obviously in market corrections small-caps are more susceptible to volatility, which explains why they are ranked towards the bottom of our analysis. But if this downtrend is only short-term in nature, basically giving the markets time to catch their breath, then small-caps might lead the rebound rally if it takes place. In the meantime however, having a disproportionate allocation in small caps could really drag down a portable alpha portfolio.

Infrared spectroscopy

2009-06-05T02:53:00.001-07:00

Infrared spectroscopy (IR spectroscopy) is the subset of spectroscopy that deals with the infrared region of the electromagnetic spectrum. It covers a range of techniques, the most common being a form of absorption spectroscopy. As with all spectroscopic techniques, it can be used to identify compounds or investigate sample composition. Infrared spectroscopy correlation tables are tabulated in the literature.

Alpha Single Unit Analyzer and Beta Single Unit Analyzer

2009-06-04T20:20:00.000-07:00

The Alpha analyzer features high quality general purpose dielectric, conductivity, impedance 2 electrode spectroscopy and gain phase measurements.

The Beta analyzer has the same functionality, but supports 3 and 4 electrode configurations in addition.

Both analyzers combine a high class precision broadband dielectric material characterization system with a typical impedance analyzer for the low and middle impedance range. This combination makes them unique and easy to use instruments with exceptional overall performance.

The Beta and Alpha analyzers cover 16 orders of magnitude impedance range, 12,5 orders of magnitude frequency range and 1m° basic phase accuracy in a single instrument. This combination makes them powerful tools for electric analysis instrumentation. As a result, the analyzers can measure the permittivity, conductivity and impedance of nearly all materials or components broadband and over a wide temperature range without changing sample geometry or sample cells.

3 or 4 electrode techniques can be advantageously used in order to partly compensate electrode - sample interface polarization or contact impedance effects.
The Beta analyzer voltage channel input impedance is 1012Ω | 10 pF which exceeds the range of most competing instruments by several orders of magnitude and therefore can be seen as a major improvement in broadband 3 and 4 electrode measurements.

The Beta and Alpha analyzers are predecessors and economical alternatives to the more powerful and flexible modular Alpha-A series, which can be extended by a series of test interfaces, which is not possible for the Beta and Alpha series.

Features

2009-06-04T20:19:00.002-07:00

For most dielectric, conductivity and impedance material measurements electrode polarization or contact effects are less prominent. In this case, the standard configuration with the sample material prepared between two parallel plate electrodes is most advantageous.

This arrangement is most simple and allows easy and flexible sample preparation. Nevertheless, the design requirements to an appropriate sample cell operating over a wide frequency, impedance and temperature range without sacrificing the Alpha-A analyzer series wide impedance range and high accuracy are extraordinary demanding.

Such a sample cell in realized in combination with an active impedance converter mounted in the cell head is realized by ZGS test interface. In contrast to other test interfaces and solutions from other manufactures, ZGS is specified at the sample electrodes position and therefore users do not have to care about artefacts by cell contributions to the measured results.

The ZG2 interface contains the same impedance converter and as ZGS, but no integrated sample cell. ZG2 can be connected by BNC terminals to any passive sample cell like e.g. BDS 1200 or any impedance under test.

Gain Phase or Frequency Response Measurements

2009-06-04T20:19:00.001-07:00

In impedance mode used for dielectric, conductivity and electrochemical impedance spectroscopy the analyzer measures the response voltage and current of a material sample to an applied sine wave signal.

In gain phase mode, a second voltage is measured instead of the current. This allows to measure two response voltages to an applied sine wave driver signal at two arbitrary points of a system under test. The two voltages are measured with the analyzer frequency response analyzer channels CH1 and CH2. The applied sine wave is created by the analyzer sine wave generator.

Gain phase measurements are supported by the Alpha-A, Alpha and Beta analyzer series.

A typical application would be to e. g. measure the transfer function of an amplifier or transformer. In this case, the analyzer generator output and input CH1 have to be connected to the amplifier input and CH2 to the amplifier output. The amplifier complex transfer function defined by Vout*/Vin* is determined by measuring the voltages at CH2 and CH1.

It should be noted, that in gain phase mode the analyzer can be operated like a digital lock-in amplifier with two input channels. The main function of a lock-in amplifier is to apply a signal with a defined frequency to a system under test and to measure a response signal. As a further lock-in amplifier feature, only the frequency component of the applied generator signal is detected in the response signal. As usually most of the response signals noise and DC errors are at other frequencies, those will therefore be suppressed. The Alpha-A, Alpha and Beta analyzers uses the same principle, but have an additional second voltage channel, wider bandwidth and better accuracy as lock-in amplifiers.

Gain phase measurements are therefore not specially related to dielectric, conductivity and impedance spectroscopy but may be of general interest if

a very small or noisy signal has to be measured with high precision;

the response of any kind of system to an applied signal in the frequency domain has to be measured.

3 and 4 Electrode Measurements

2009-06-04T20:14:00.002-07:00

In a measurement of a material prepared between two parallel plate electrodes with spacing d, the complex permittivity, conductivity or impedance is evaluated from the phase sensitive measurement of the electrodes voltage difference US and current IS. This method presumes that the applied voltage US drops homogeneously within the material by creating a constant electric field E=US/d.

This presumption does not hold if at the electrode sample interface electrical inhomogeneous layers exist which create a significant voltage drop and by this reduce the E-field in the sample. Such layers may be created by

accumulation of ions at the electrode for ion conductors like e.g. electrolytes and many liquids (water, electrode polarization);

bad electrode sample contact connections (contact impedance).

Similar effects may be created by none zero impedance of the cables from the electrodes to the analyzer voltage and current terminals for low impedance samples.

The outer two electrodes correspond to the parallel plates of a standard 2-electrode configuration. The voltage is measured by two additional (e.g. ring or needle) electrodes in the inner sample area where no interface effects exist and the field is homogenous.

If the two voltages are measured by an instrument with infinite input impedance, no current flows in the voltage electrodes and therefore no ions can accumulate. Due to the zero current, existing contact or cable impedance do not create a voltage drop, too. In this case, the electrical parameters of the material portion between the voltage electrodes can be evaluated without interface polarization and contact or cable effects from the voltage difference between the voltage electrodes and the current flowing through the outer electrodes. The only, but in practice crucial and not always fulfilled presumption is the sufficient high input impedance of the voltage channels.

The ZG4 and POT/GAL Test Interfaces of the Alpha-A analzer series and the Beta analyzer series can in addition to 2-wire- be configured for 3-, or 4-wire measurements. Their input impedance is higher as 1012 Ω in parallel with 10 pF which exceeds the range of most competing instruments by several orders of magnitude and therefore can be seen as a major improvement in broadband 3- and 4-electrode dielectric, conductivity and electrochemical impedance measurements.

On the other hand, especially for high impedance samples at high frequencies the 10 pF input capacity may be in the same order of magnitude as the sample capacity and may contribute to the measured result. 3- and 4-four electrode measurements therefore in practice always require a detailed analysis of the currents flowing into the voltage terminals and the related voltage drop at contacts or electrode interfaces.

Alpha-A High Performance Modular Measurement System

2009-06-04T20:14:00.001-07:00

This system features high performance dielectric, conductivity, electrochemical, impedance and gain phase measurements in the frequency domain. It is our latest, most powerful and flexible system and recommend for new instrument designs.

The system is modular and based on an Alpha-A mainframe unit which usually is combined with one or more test interfaces optimized for special functionality. All test interfaces for impedance measurement offer in addition high general purpose performance like highest accuracy and ultra wide impedance and frequency range.

This makes the Alpha-A system an unique and easy to use instrument with exceptional overall performance which suits in addition many special requirements like e.g. 4 electrode high impedance, high voltage, high current measurements and potentiostat, galvanostat functions for electrochemical impedance spectroscopy EIS.

The Alpha-A family covers 18 orders of magnitude impedance range (16 orders for each impedance test interface), 12.5 orders of magnitude frequency range and 2m° basic phase accuracy.

This combination makes the Alpha-A system a powerful tool which sets the pace for electric frequency domain analysis instrumentation. As a result, permittivity, conductivity and impedance of nearly all materials or components including special functions can be measured broadband and over a wide temperature range without changing sample geometry or sample cells.

Features of Alpha-A Mainframe + Test Interface Family

2009-06-04T20:10:00.000-07:00

Broad frequency range 3.10-5 .. 2.107 Hz including low frequencies for characterization of dielectric relaxations, electrochemical and high impedance effects.

Ultra wide impedance range 10-3 .. 1015 Ω (18 decades) covers range from conductors to best isolators.

Ultra wide capacity range 10-15 .. 1 F allows broadband measurement of smallest capacities down to 1 fF.

High phase 2.10-3 ° and loss factor tan(δ) absolute accuracy 3.10-5 for low loss dielectric materials and isolators broadband characterization.

Supports a series of test interfaces for customized applications with special functionality.

Supports non linear Dielectric, Conductivity and Impedance Spectroscopy or gain phase measurements in combination with all test interfaces.

Supports high speed measurements rates up to 157 impedance or 210 gain phase measurement points per second via the GPIB port for online monitoring of time variant processes in the 5 ms range by mainframe option F.

New test interface concept with adaptive system functionality and single port operation by high level GPIB commands for easy and straightforward implementation in own programs or existing measurement set-ups.

Automatic self calibration and diagnosis by user cancels out long term internal drift and verifies functionality.

Precision digital frequency response analyzer up to 40 MHz for two channel gain phase measurements with 0.001° phase - and 10-5 in amplitude resolution included. Operates like a broadband lockin amplifier with two channels, extended accuracy and frequency range.

Optional control WinDETA software for turnkey calibration, operation, data evaluation, 2- and 3- dimensional graphical representation including non linear spectroscopy.