WO2003005061A1

WO2003005061A1 - Digital processing device

Info

Publication number: WO2003005061A1
Application number: PCT/US2002/022294
Authority: WO
Inventors: L. Stephen Price; Vassili Kobyltchak
Original assignee: Keymaster Technologies, Inc.
Priority date: 2001-06-30
Filing date: 2002-06-28
Publication date: 2003-01-16

Abstract

Apparatus and methods for analyzing data from electronic devices, such as portable electronic devices (25) for x-ray (29) fluorescence (31) analysis (23) are described. The apparatus obtains better resolution of the data than those apparatus and methods currently available. The invention obtains data with better resolution by combining both analog and digital signal processing into a single mechanism (23), keeping background noise to a minimum and maximizing count rates and gain without flooding the system (25).

Description

DIGITAL PROCESSING DEVICE

FIELD OF THE INVENTION

The invention generally relates to apparatus and methods for processing digital signals. More particularly, the invention relates to apparatus and methods for processing digital signals from electronic devices. Even more particularly, the invention relates to apparatus for processing digital signals for an x-ray device, including portable x-ray devices, and methods for using the same.

BACKGROUND OF THE INVENTION

There has been significant interest in apparatus and methods for identifying and verifying various articles or products such as explosives, ammunition, paint, petroleum products, and documents. Known methods used to identify and verify generally involve adding and detecting materials like code-bearing microparticles, bulk chemical substances, and radioactive substances. Other methods used for identifying and verifying articles include those described in U.S. Patent Nos. 6,030,657, 6,024,200, 6,007,744, 6,005,915, 5,849,590,

5,760,394, 5,677,187, 5,474,937, 5,301,044, 5,208,630, 5,057,268, 4,862,143, 4,390,452,

4,363,965, and 4,045,676, as well as European Patent Application Nos. 0911626 and 0911627, the disclosures of which are incorporated herein by reference.

It is also known to apply materials to articles in order to track, for example, point of origin, authenticity, and their distribution. In one method, inks that are transparent in visible light are sometimes applied to materials and the presence (or absence) of the ink is revealed by ultraviolet or infrared fluorescence. Other methods include implanting microscopic additives that can be detected optically. However, detecting these materials is primarily based on optical or photometric measurements.

Numerous devices are known for identifying and verifying articles containing such materials (called taggants) by x-ray fluorescence (XRF). See, for example, U.S. Patent Nos. 5,461,654, 6,130,931, 6,041,095, 6,075,839, 6,097,785, and 6,111,929, the disclosures of which are incorporated herein by reference. Unfortunately, many of the known apparatus for are unsatisfactory for several reasons. First, they are often difficult and time-consuming to use. In many instances, a sample of the article must be sent to an off-site laboratory for analysis. In other instances, the apparatus are often expensive, large, and difficult to operate. For example, the known apparatus and methods for identification and verification are also unsatisfactory because the devices employed are usually not portable.

Even when portable, their ability to adequately analyze the data produced from the device is also quite limited. Because of the manner in which XRF operates, it is very difficult to process and analyze the data. In particular, a spectrum of data is produced during the XRF process. The spectrum contains the desired data finely interspersed with a lot of undesired data. Unfortunately, known devices are not very efficient for distinguishing between the desired and undesired data.

SUMMARY OF THE ΓNVENTION

The invention provides apparatus and methods for analyzing data from electronic devices, such as portable electronic devices for x-ray fluorescence analysis. The apparatus obtains better resolution of the data than those apparatus and methods currently available.

The invention obtains data with better resolution by combining both analog and digital signal processing into a single mechanism, keeping background noise to a minimum and maximizing count rates (and gain) without flooding the system.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1, 2a, 2b, 3, 4a, 4b, and 5-9 are views of one aspect of apparatus and methods according to the invention, in which:

Figure 1 generally depicts the operation of XRF;

Figure 2a and 2b illustrate the operation of XRF at the molecular level;

Figure 3 shows an exemplary x-ray spectrum, e.g., for paper; Figure 4a and 4b depict two aspects of the of the XRF apparatus of the invention;

Figure 5 illustrates exemplary energy levels of x-rays in an x-ray spectrum;

Figure 6 shows another aspect of the XRF apparatus of the invention; and

Figures 7 illustrates a block diagram of a processing board of in one aspect of the invention;.

Figure 8 depicts an x-ray spectrum product without the processing board in one aspect of the invention; and

Figure 9 shows an x-ray spectrum product with the processing board in one aspect of the invention. Figures 1, 2a, 2b, 3, 4a, 4b, and 5-9 presented in conjunction with this description are views of only particular — rather than complete — ortions of apparatus and methods according to the invention. Together with the following description, the Figures demonstrate and explain the principles of the invention.

Figures 1, 2a, 2b, 3, 4a, 4b, and 5-9 presented in conjunction with this description are views of only particular — rather than complete — portions of apparatus and methods for analyzing data according to the invention.

DETAILED DESCRIPTION OF THE INVENTION The following description provides specific details in order to provide a thorough understanding of the invention. The skilled artisan would understand, however, that the invention can be practiced without employing these specific details. Indeed, the invention can be practiced by modifying the illustrated apparatus and method and can be used in conjunction with apparatus and techniques conventionally used in the industry. For example, the invention is described with respect to analyzing data from an XRF detecting apparatus. The invention described below, however, could be easily modified to analyze data from devices other than XRF apparatus, such as portable devices, benchtop systems, and x-ray devices. Indeed, the power supply device and method of the invention could be used to analyze data from any known electronic detection device, whether portable or not, producing a spectrum of data that needs to be analyzed.

In one aspect, the invention uses x-ray fluorescence analysis to detect at least one taggant intrinsically or extrinsically present in the material of a product or article. With x-ray fluorescence (XRF) analysis, x-rays produced from electron shifts in the inner shell(s) of atoms of the taggants and, therefore, are not affected by the form (chemical bonding) of the article being analyzed. The x-rays emitted from each element bear a specific and unique spectral signature, allowing one to determine whether that specific taggant is present in the product or article. Figures 1, 2a, and 2b represent how it is believed XRF generally operates. In Figure

1, primary gamma rays or x-rays 40 are irradiated on a sample of a target material 46 of article 42. Secondary x-rays 44 are emitted from that sample of target material 46.

In Figures 2a and 2b, atom 48 of a taggant located within target material 46 has nucleus 50 surrounded by electrons 52 at discrete distances from nucleus 50 (called electron shells). Each electron shell has a binding energy level equal to the amount of energy required to remove that electron from its corresponding shell. The innermost shell is the K shell, and has the highest binding energy level associated with it. Electron 54 is located within K shell 56.

Primary x-ray or gamma ray photon 40 impacting atom 48 has a given energy. If that energy is greater than the binding energy level of K shell 56, the energy of x-ray photon 40 is absorbed by atom 48, and one of the electrons in K shell 56 (i.e., electron 54) is ejected. With a vacancy now in K shell 56 left by electron 54, atom 48 is energetic and unstable. To become more stable, that vacancy in K shell 56 can be — and usually is — filled by an electron located in a shell with a lower binding energy level, such as L-shell electron 58 in L shell 60. As L-shell electron 58 fills the vacancy in K shell 56, atom 48 emits a secondary x-ray photon 44. The energy levels (or corresponding wavelengths) of such secondary x-ray photons are uniquely characteristic to each taggant, allowing the presence or absence of any specific taggant to be determined. As shown in Figure 3, the x-rays which are detected have various energies, e.g., there is a broad band of scattered x-rays with energies less than and greater than those of the exciting atom. Figure 3 illustrates this spectrum for paper as the target material. Within this broad band, there are peaks due to the excitation of the taggant(s) in the sample. The ratio of the intensity of the radiation in any peak to the intensity of the background at the same energy (known as the peak-to-background ratio) is a measure of the concentration of the element which has characteristic X-rays at the energy of that peak, e.g., the taggant.

In one aspect of the detection method of the invention, at least one target material believing to contain known concentrations of the taggant(s) of interest is selected. The XRF analysis is performed on that target material (or a sample thereof) using a detection device or apparatus containing an x-ray radiation source ("source"), x-ray radiation detector ("detector"), support means, analyzer means, and calibration means.

One aspect of the detection device of the invention is illustrated in Figure 4a. In this Figure, the detection apparatus 25 has an ordinary x-ray fluorescence spectrometer capable of detecting elements present in a coating, package or material. X-rays 29 from a source (e.g., either x-ray tube or radioactive isotope) 20 impinge on a sample 11 which absorbs the radiation and emits x-rays 31 to an x-ray detector 21 and analyzer 23 capable of energy or wavelength discrimination. This is accomplished by using a commercially available x-ray spectrometer such as an Edax DX-95 or a MAP-4 portable analyzer, commercially available from Edax Inc., Mahwah, New Jersey. Part of analyzer 23 includes a computerized system 27.

Another aspect of the detection apparatus of the invention is illustrated in Figure 4b. In this Figure, the detection apparatus 25 has an instrument housing 15 which contains the various components. Gamma rays or x-rays 30 from a source (e.g., either x-ray tube or radioactive isotope) 20 are optionally focused by aperture 10 to impinge on a sample 11. Sample 11 contains the at least one taggant which absorbs the radiation and emits x-rays 31 to an x-ray detector 21. Optionally, analyzing means can be incorporated within housing 15. The invention, however, is not limited to the detection apparatus depicted in Figures 4a and 4b. Any suitable source, or plurality of sources, known in the art can be used as the source in the detection device of the present. See, for example, U.S. Patent Nos. 4,862,143, 4,045,676, 6,005,915, and 6,178,226, the disclosures of which are incorporated herein by reference. During the XRF detection process, the source bombards the taggant with a high energy beam. The beam may be an electron beam or electromagnetic radiation such as X- rays or gamma rays. The source, therefore, may be any material emitting such high energy beams. Typically, these have been x-ray emitting devices such as x-ray tubes or radioactive sources. The x-ray source is powered by any suitable power supply, as described below. To target, the beam can be focused and directed properly by any suitable means such as an orifice or an aperture. The configuration (size, length, diameter...) of the beam should be controlled, as known in the art, to obtain the desired XRF detection. The power (or energy level) of the source should also be controlled, as known in the art, to obtain the desired XRF detection. The source(s) can be shielded and emit radiation in a space limited by the shape of the shield. Thus, the presence, configuration, and the material used for shielding the source should be controlled for consistent XRF detection. Any suitable material and configuration for that shield known in the art can be employed in the invention. Preferably, any high- density materials used as the material for the shield, e.g., tungsten or brass. Any suitable detector, or plurality of detectors, known in the art can be used as the detector in the detection device of the invention. See, for example, U.S. Patent Nos. 4,862,143, 4,045,676, and 6,005,915, the disclosures of which are incorporated herein by reference. Any type of material capable of detecting the photons omitted by the taggant may be used. Silicon and CZT (cadmium-zinc-telluride) detectors have been conventionally used, but others such as proportional counters, germanium detectors, or mercuric iodide crystals can be used.

Several aspects of the detector should be controlled to obtain the desired XRF detection. First, the geometry between the detector and the target material should be controlled. The XRF detection also depend on the presence, configuration, and material — such as tungsten and beryllium — used as a window to allow x-rays photons to strike the detector. The age of the detector, voltage, humidity, variations in exposure, and temperature can also impact the XRF detection and, therefore, these conditions should be controlled. The analyzer means sorts the radiation detected by the detector into one or more energy bands and measures its intensity. Thus, any analyzer means performing this function could be used in the invention. The analyzer means can be a multi-channel analyzer for measurements of the detected radiation in the characteristic band and any other bands necessary to compute the value of the characteristic radiation as distinct from the scattered or background radiation. See, for example, U.S. Patent Nos. 4,862,143, 4,045,676, and 6,005,915, the disclosures of which are incorporated herein by reference.

The XRF also depends on the resolution of the x-rays. Background and other noise must be filtered from the x-rays for proper measurement, e.g., the signals must be separated into the proper number of channels and excess noise removed. The resolution can be improved by cooling the detector using a thermoelectric cooler — such as a nitrogen or a peltier cooler — and/or by filtering. Another way to improve this resolution is to use preamplifiers.

The support means supports the source and detector in predetermined positions relatively to a sample of the target material to be irradiated. Thus, any support means performing this function could be used in the invention. In one example, the support means comprises two housings, where the source and detector are mounted in a first housing which is connected by a flexible cable to a second housing in which the analyzer means is positioned as illustrated in Figure 4a. If desired, the first housing may then be adapted to be hand-held. In another example, the source and detector as well as the other components of the detection device are mounted in a single housing as illustrated in Figure 4b.

The calibration means are used to calibrate the detection apparatus, thus insuring accuracy of the XRF analysis. In this calibration, the various parameters that could be modified and effect the measurement are isolated and calibrated. For example, the geometrical conditions or arrangements can be isolated and calibrated. In another example, the material matrix are isolated and calibrated. Preferably, internal (in situ) calibration during detection is employed as the calibration means in the invention. Components, such as tungsten shielding, are already present to internally calibrate during the XRF analysis. Other methods, such as fluorescence peak or Compton backscattering, could be used for internal calibration in the invention.

Analyzer means, which includes a computerized system 27, is coupled to, receives, and processes the output signals produced by detector 21. The energy range of interest, which includes the energy levels of the secondary x-ray photons 44 emitted by the taggant(s), is divided into several energy subranges. Computerized system 27 maintains counts of the number of X-ray photons detected within each subrange using specific software programs, such as those to analyze the detection and x-ray interaction and to analyze backscatter data. After the desired exposure time, computerized system 27 with display menus stops receiving and processing output signals and produces a graph of the counts associated with each subrange.

Figure 5 is a representative graph of the counts associated with each subrange. This graph is essentially a histogram representing the frequency distribution of the energy levels El, E2, and E3 of the detected x-ray photons. Peaks in the frequency distribution (i.e., relatively high numbers of counts) occur at energy levels of scattered primary x-ray photons as well as the secondary x-ray photons from the taggant(s). A primary x-ray photon incident upon a target material may be absorbed or scattered. The desired secondary x-ray photons are emitted only when the primary x-ray photons are absorbed. The scattered primary x-ray photons reaching the detector of the system create an unwanted background intensity level. Accordingly, the sensitivity of XRF analysis is dependent on the background intensity level, and the sensitivity of XRF detection may be improved by reducing the amount of scattered primary x-ray photons reaching the detector. The peak occurring at energy levels of scattered primary x-ray photons is basically ignored, while the other peaks — those occurring at El, E2, and E3 — are used to identify the at least one taggant present in the target material. Besides the parameters described above, at least two other parameters must be controlled during the process of XRF detection. First, the media (such as air) through which the gamma rays (and x-rays) must travel also impacts the XRF. Therefore, the different types of media must be considered when performing the XRF analysis. Second, the methods used to interpret and analyze the x-rays depend, in large part, on the algorithms and software used. Thus, methods must be adopted to employ software and algorithms that will consistently perform the XRF detection.

These two parameters, plus those described above, must be carefully accounted for and controlled to obtain accurate measurements. In one aspect of the intention, these parameters could be varied and controlled to another provide a distinct code. For example, using a specific source and a specific detector with a specific measuring geometry and a specific algorithm could provide one distinct code. Changing the source, detector, geometry, or algorithm could provide a whole new set of distinct codes.

Figure 6 illustrates a preferred apparatus and detection method according to the invention. In this Figure, detection apparatus 25 is capable of detecting at least one taggant present in target material 10. Detection apparatus 25 is a portable device that is small enough to be hand-held. Detection apparatus 25 contains all the components discussed above (i.e., source, detector, analyzer means, and calibration means) in a single housing, thus allowing the portability and smaller size. As mentioned above, analyzer means includes a computerized system 27 that receives and processes the output signals produced by detector 21. Computerized system 21 maintains the counts of the number of X-ray photons detected using specific software programs and algorithms. Computerized system 27 produces a graph of the counts associated with each subrange. Typically, the analyzer means processed the signals using two separate mechanisms — one mechanism for analog signals and one for digital signals. The analog mechanism often encompassed an analog circuit board containing signal amplifiers, filters, shaping circuits, and power supplies. The digital mechanism often encompassed a digital circuit board with a processor, Erasable Programmable Logic Device (EPLD) memory, and input/output (I/O) means.

Unfortunately, the combination of these two mechanisms was very inefficient. Much of the analog signal was lost or flooded with noise (e.g., background noise) before it was digitized. This occurrence resulted in low count rates, artifacting (creation of false signals), and/or erratic behavior. As well, powering two separate mechanisms was a very inefficient use of power.

The invention overcomes these — as well as other — disadvantages by combining these two separate mechanisms into a single one, e.g., combining the functions into a single mechanism. When combined as detailed herein, lead lengths are made shorter, noise is kept to a minimum, and count rates (and gain) can be maximized without flooding the system. Any single mechanism or device combining such functions and accomplishing these advantages (and overcoming the above disadvantages) can be used in the invention.

As well, the invention has an additional advantage. The invention redistributes the duties between the analog and digital mechanisms, making the distribution of the duties more efficient and effective. In additional, by re-distributing the duties the invention allows feedback from the digital portion of the board to the analog portion, providing better operation and analyzation.

In one aspect of the invention, the analog and digital mechanisms (or boards) are combined into a single circuit board, the digital signal processing (DSP) or digital pulse processing (DPP) means. In one aspect of the invention, the DSP or DPP means are a digital processor a digital processing board (DPB). The DPB board limits the amount of analog operations. Instead, the analog signals are amplified and filtered, converted to a digital signal, and then processed digitally by the DPB. The DPB can — with appropriate modifications — digitally control the gain, shaping time, threshold, and number of channels. As well, the DPB is capable of temperature feedback and calibration. All of these functions can be modified (and improved) by reprogramming the components of the DPB using algorithms designed for the desired modification(s). The DPB of the invention contains several components and circuitry to accomplish the functions described above. Figure 7 represents one aspect of the DPB of the invention.

Figure 7 illustrated an example of a block diagram for the functions and components of the

DPB. In this aspect of the invention, detector 21 detects the x-rays 31 emitted from the sample 11, producing an analog signal 102 that is fed into the analyzer means.

Analog signal 102 comprises the energy of the photons of x-rays 31, but is a relatively weak signal and contains a fair amount of unwanted signals (or noise). To increase the quality of that signal, it is amplified and filtered to remove as much of the noise as possible. To that end, input signal 102 is transmitted to preconditioning circuit 104. That circuit serves several roles. First, the preconditioning circuit is amplified. The preconditioning circuit can contain any suitable means to amplify the analog signal, such as circuits that include optional amplifiers, and/or comparators.

Second, preconditioning circuit scales the signal to fit a desired range. It may accomplish this using any means known in the art, such as an opamp or comparator circuit. The signal may be scaled to any range, depending on the next component in the DPB. In the aspect of the invention illustrated in Figure 7, the signal is scaled for the 4V input range of the analog to digital converter (ADC) 106, e.g., about 0.5 V to about 4.5 V.

The third function of the preconditioning circuit is to act as a filter. This circuit functions to clean up the noise from input signal 102 before it is digitized later. Any suitable mechanism known in the art which accomplishing this filtering function can be used. In one aspect of the invention, a 200 ns 3^rd order active low pass-filter is used. '

In one aspect of the invention, different devices can be combined to serve as the preconditioning circuit. In an alternative aspect of the invention, the single device can be used to serve all functions of the preconditioning circuit simultaneously. Any suitable single device known in the art can be used, such as a preamplifier integrated circuit chip.

The analog signal 108 from the preconditioning circuit is then transmitted to means for converting the analog signal to a digital signal. Any converting means known in the art can be employed in the invention, such as ADC 106. The ADC 106 samples the incoming signal 108, which is typically at a range of about 1 MHz to about 20 MHz, and preferably about 8 MHz. The higher the frequency the more power it consumes. The ADC then converts the signal to a 16-bit word signal. Finally, the ADC transmits the data to the next component of the DPB at a range of about 1 MHz to about 20 MHz, and preferably about 1 MHz. Optionally, even though not preferred, the sampling rate of the ADC can be increased by sacrificing power.

Any suitable apparatus known in the art can be used as the converting means. Suitable apparatus include integrator, sampling circuit or switcher circuit. In one aspect of the invention, an analog-to-digital converter chip is used as the converting means. In a preferable aspect of the invention, the AD9260 chip (made by Analog Devices) is used as the < converting means.

The digital signal from the converting means is then transmitted to the next component of the DPB, the digital signal processor 120. As described in more detail below, the digital signal processor carries out numerous functions, as well as processing the digital signal. Any suitable means known in the art which can accomplish these various functions can be used in the DPB of the invention. In one aspect of the invention, this processor is a programmable logic integrated circuit such as a FPGA Field Programmable Gate Array (FPGA). In a preferable aspect of the invention, this processor is a Xilinx FPGA XC2S200 integrated circuit. The DSP chip performs the majority of the processing operations of the DPB. . In the current board the DSP performs the major signal filtering. As mentioned above, the duties are shifted and the analog portion of the board (preconditioning) filters out only the high frequency wing of the whole signal spectrum, where there are no valid signal Fourier components. The major Fourier range, where we have the mix of valid signal and noise from various sources is processed by the DSP in real time. The main advantage is to split filtering between analog and digital portions so that the most critical steps would be made most efficiently and flexible. Another advantage of the DSP is that it does not introduce any additional noise to what existed on the phase of analog to digital conversion. That means that the digital shaping and extracting algorithm and other algorithms used in the DSP being implemented in the analog form would require so many active components that their noise and power consumption would perish the beauty of the algorithm.

Another duty of the DSP chip is to prepare the spectrum. In this aspect of the invention, the DSP chip scales the events according to the calibration constants and fills the internal array of channels. Rescaling is solved by pipelined real time dividers with special means for avoiding "holes" in the spectrum when fractional scaling factors are required. In other words, pipelining streams the data quickly as additional data is being taken and rescaling uses special circuitry that works with this data stream and continue to make the data look smooth without having "holes" or jerks in the data information. Another duty of the DSP chip is changing the parameters on-the-fly or during operation so they would reflect current conditions optimally.

In one aspect of the invention, the digital signal processor can be modified to change its operating parameters and/or the functions it performs, thereby allowing it to be used for any type of system. For example, the digital signal processor can be modified to changes the number of channels it analyzes, the signal threshold, or shaping time. When the digital signal processor is a DSP chip, it can be modified because it is a programmable logic chip.

In one aspect of the invention, the DSP chip is programmed using a library of algorithms. Each algorithm interrogates (or evaluates) a select portion of the waveforms that would be valid for that area of the total signal. For example, the total incoming signal often represents waveforms that span a wide range of x-ray energies from a fluorescing sample. The behavior of the waveforms offer differ for lighter energy producing elements than for heavier higher energy elements. When combined together in a library, the algorithms are extremely effective for evaluating this wide range of x-ray energies. After manipulating the data, the DSP chip then converts the data into a form that can be transmitted and displayed. In one aspect of the invention, the signal transmitted from the DSP chip is an 8-bit data stream. This data stream is split to communications port 116 and to a controlling means 118. The controlling means 118 operates to accomplish several functions. First, the controlling means serves to control the boot-up operation of the DPB via flash memory 120. Second, the controlling means serves in a feedback capacity, as described below. Any suitable control mechanism operating to provide the above functions can be used in the invention. Examples of such control mechanisms include microprocessor chips, portable computer commands, and controller integrated circuits. In one aspect of the invention, a Peripheral Interface Controller (PIC) processor is used in the invention as part of the controlling means. In a preferred aspect of the invention, the PIC processor is the microprocessor chip PIC16LF877 (made by MicroChip Corporation). Part of the PIC processor contains a software program that permanently resides on the PIC processor. This software program is used during the boot-up process of the DPB in two different modes. In normal mode, the software program passes control to the software application previously loaded. Thus, the behavior of the controller is controlled by that previously-loaded application. In a program mode, this software program waits for a software application to be loaded by the user.

Another component of the DPB is flash memory 120. Any suitable flash memory mechanism known in the art can be used in the invention. In one aspect of the invention, the flash memory is an electronically erasable programmable random access memory (EEPROM) integrated circuit. In a preferable aspect of the invention, the flash memory is a AM29LV040 chip. The flash memory retains the resident and default values needed during boot-up of the DPB. When powered up, the DPB uses these values to begin operation of the DPB. Depending on the needs of the user, these default and resident values can be changed using controlling means 118.

In one aspect of the invention, the flash memory is used for storing the current configuration for the DSP chip. In this configuration, the memory used for the DSP configuration occupies only a minor portion — e.g., about 30% — of the available memory. The major portion — e.g., about 70% — of the available memory can be used for other purposes, e.g., alternative algorithms, default parameters, and or various DPB information. The major portion of this memory is accessed by the controlling means and can be reprogrammed through one of the ports (including the communications port 166) on the DPB. The data stream from the DSP chip is also transmitted to the communications port 116. The communications port 116 serves as the gate between the user interface (e.g., computer system) and the DPB. Any suitable communications port known in the art that operates as such a gate can be employed in the invention. In one aspect of the invention, communication port meeting the IEEE RS-232 standard can be used in the invention. An example of such a port would be the MAX-232A.

In one aspect of the invention, additional components can be added to the DPB. In another aspect of the invention, the components of the DPB can be configured differently to achieve different or additional options or functions.

In another aspect of the invention, additional components can be added to the analyzation means of the invention. For example, as described above the DPB is used by itself, but — if desired — the DPB can be mated with a second processor board for added functionality. In this example, the added functions could be deconvolution, chemical elements, detection, or analysis.

In another aspect of the invention, the analyzation means can be modified to contain a temperature feedback mechanism. In this aspect of the invention, the analyzation means monitors the temperature of the detector and the pettier cooler. The analyzation means also comprises a feedback controller. When the desired temperature is reached, the feedback controller limits the current to the pettier cooler, thereby causing the temperature to remain stable. Any suitable feedback controller serving this function can be used in the invention, such as a standard PIC controller for standard analog inputs. In a preferable aspect of the invention, the ambient temperature can be sensed by LM34D, and the temperature of the pettier cooler of the detector was sensed by the built-in diode and then amplified by a AD4274A fixed gain OPAMP. For controlling the detector temperature via the Peltier Cooler, the combination of a DAC AD5330 and LM2651-ADJ DC-DC converter were used. EXAMPLE A plastic substrate was obtained and then tagged with elemental molybdenum. An XRF device without a digital processing board of the invention was used to analyze the sample. That device produced the spectra as depicted in Figure 8. The XRF device was then re-configured with a digital processing board and used to analyze the sample. The reconfigured device produced the spectra depicted in Figure 9.

The spectra in Figure 8 does not have the resolution of the spectra in Figure 9. To analyze a sample containing elements that fluoresce x-rays with energies next to the energy of the molybdenum, the Figure 9 spectra will yield much better elemental content accuracy than the Figure 8 spectra.

Having described the preferred aspects of the invention, it is understood that the invention defined by the appended claims is not to be limited by particular details set forth in the above description, as many apparent variations thereof are possible without departing from the spirit or scope thereof.

Claims

CLAIMSWe claim:

1. A device for analyzing data, comprising: means for converting an analog signal to a digital signal; means for processing the digital signal to increase the resolution thereof; and means for converting the digital signal and transmitting the converted signal to be displayed; wherein the analog converting means, processing means, and digital converting means are all contained within a single circuit board.

2. The device of claim 1, wherein the analog converting means is contained on the analog portion of the circuit board and the processing and digital converting means are contained on the digital portion of the circuit board.

3. The device of claim 2, wherein the analog portion also amplifies and filters the analog signal.

4. The device of claim 3, wherein the analog signal is amplified and filtered by a preconditioning circuit.

5. The device of claim 3, wherein the analog signal is converted to a digital signal by a converter chip.

6. The device of claim 2, wherein the digital portion introduces no additional noise.

7. The device of claim 2, wherein the resolution of the digital signal is increased by using a programmable logic integrated circuit.

8. The device of claim 7, wherein the programmable logic integrated circuit can be reprogrammed by a library of algorithms.

9. A device for analyzing an x-ray signal, comprising: means for converting an analog signal in to a digital signal; means for processing the digital signal to increase the resolution thereof; and means for converting the digital signal and transmitting the converted signal to be displayed; wherein the analog converting means, processing means, and digital converting means are all contained within a single circuit board.

10. The device of claim 9, wherein the analog converting means is contained on the analog portion of the circuit board and the processing and digital converting means are contained on the digital portion of the circuit board.

11. An x-ray fluorescence device, comprising: means for detecting an x-ray; a circuit board containing means for converting an analog signal in to a digital signal, means for processing the digital signal to increase the resolution thereof, and means for converting the digital signal and transmitting the converted signal; and means for displaying the converted signal.

12. The device of claim 11, wherein the analog converting means is contained on the analog portion of the circuit board and the processing and digital converting means are contained on the digital portion of the circuit board.

13. The device of claim 12, wherein the analog portion also amplifies and filters the analog signal.

14. The device of claim 13, wherein the analog signal is amplified and filtered by a preconditioning circuit.

15. The device of claim 13, wherein the analog signal is converted to a digital signal by a converter chip.

16. The device of claim 12, wherein the digital portion introduces no additional noise.

17. The device of claim 12, wherein the resolution of the digital signal is increased by using a programmable logic integrated circuit.

18. The device of claim 17, wherein the programmable logic integrated circuit can be reprogrammed by a library of algorithms.

19. The device of claim 18, wherein the device is portable.

20. A method for analyzing data, comprising: providing a spectrum of data; providing a circuit board containing means for converting an analog signal in to a digital signal, means for processing the digital signal to increase the resolution thereof, and means for converting the digital signal and transmitting the converted signal; and analyzing the data using the circuit board.

21. A method for processing data, comprising: providing a spectrum of data; providing a circuit board containing means for converting an analog signal in to a digital signal, means for processing the digital signal to increase the resolution thereof, and means for converting the digital signal and transmitting the converted signal; and processing the data using the circuit board.

22. A method for analyzing x-rays, comprising: providing an x-ray; providing a circuit board containing means for converting an analog signal in to a digital signal, means for processing the digital signal to increase the resolution thereof, and means for converting the digital signal and transmitting the converted signal; and analyzing the x-ray using the circuit board.