| Energy Dispersive X-ray Fluorescence (EDXRF) Analysis EDXRF Spectrometer A high-powered, flexible, sensitive, EDXRF benchtop instrument can be customized for a variety of applications. Many industries would benefit from the compact size and powerful analytical capabilities of the EX-Calibur. The compact spectrometer fits conveniently on a traditional laboratory bench and includes a completely integrated computer system. The robust design and build makes the instrument ideal for a mobile laboratory. It meets MIL specifications for shock testing. The analyzer provides non-destructive qualitative and quantitative determination of elements from Na - U. The instrument is a compact tool with the performance of a traditional laboratory unit. Features
The field of X-ray fluorescence (XRF) spectroscopy is challenging and exciting. XRF was originally used to analyze geological samples. As the technique developed, with the advancements in computers and technology, XRF found its place in many different types of analytical laboratories. With advantages such as easy sample preparation, nondestructive rapid multi-element analysis, and the ability to screen unknowns in a wide array of sample matrices such as liquids, solids, slurries, powders, pastes, thin films, air filters, and many others; XRF offers a perfect compliment to other types of analytical equipment found in the analytical lab . Because of these advantages the technique has a broad appeal to research, industrial, and quality assurance analysts. Introduction Energy dispersive x-ray fluorescence (EDXRF) relies on the detector and detector electronics to resolve spectral peaks due to different energy x-rays. It wasn't until the 1960's and early 1970's that electronics had developed to the point that high-resolution detectors, like lithium drifted silicon, Si(Li), could be made and installed in commercial devices. Computers were also a necessity for the success of EDXRF even if they where often as large as the instrument itself. back to top Hardware EDXRF is relatively simple and inexpensive compared to other techniques. It requires and x- ray source, which in most laboratory instruments is a 50 to 60 kV 50-300 W x-ray tube. Lower cost benchtop or handheld models may use radioisotopes such as Fe-55, Cd-109, Cm-244, Am-241 of Co-57 or a small x-ray tube. The second major component is the detector, which must be designed to produce electrical pulses that vary with the energy of the incident x- rays. Most laboratory EDXRF instruments still use liquid nitrogen or Peltier cooled Si(Li) detectors, while benchtop instruments usually have proportional counters, or newer Peltier cooled PIN diode detectors, but historically sodium iodide (NaI) detectors were common. Some handheld device use other detectors such as mercuric Iodide, CdTe, and CdZnTe in addition to PIN diode devices depending largely on the x-ray energy of the elements of interest. The most recent and fastest growing detector technology is the Peltier cooled silicon drift detector (SDD), which are available in some laboratory grade EDXRF instruments. After the source and detector the next critical component are the x-ray tube filters, which are available in most EDXRF instrument. There function is to absorb transmit some energies of source x-rays more than other in order to reduce the counts in the region of interest while producing a peak that is well suited to exciting the elements of interest. Secondary targets are an alternative to filters. A secondary target material is excited by the primary x-rays from the x-ray tube, and then emits secondary x-rays that are characteristic of the elemental composition of the target. Where applicable secondary targets yield lower background and better excitation than filter but require approximate 100 times more primary x-ray intensity. One specialized form of secondary targets is polarizing targets. Polarizing XRF takes advantage of the principle that when x-rays are scattered off a surface they a partially polarized. The target and sample are place on orthogonal axis' to further minimize the scatter and hence the background at the detector. Fixed or movable detector filters, which take advantage of non-dispersive XRF principles, are sometimes added to EDXRF devices to further improve the instruments effective resolution or sensitivity forming a hybrid EDX/NDX device. Applications EDXRF can be used for a tremendous variety of elemental analysis applications. It can be used to measure virtually every element form Na to Pu in the periodic table, in concentrations ranging from a few ppm to nearly 100 percent. It can be used for monitoring major components in a product or process or the addition of minor additive. Because XRF's popularity in the geological field, EDXRF instruments are often used alongside WDXRF instruments for measuring major and minor components in geological sample. Metals represent a broad group of applications that are generally ideal for XRF. Almost all elements in every step of the process from ores to finished alloys can be excited and measured by XRF. Scrap metals are usually sorted by XRF as well, where the hand help instruments are a practical choice. Alloy Analysis and Scrap Sorting All alloys of virtually any shape and size are suitable for XRF analysis. Low cost hand held and benchtop instruments can be used to measure the major elements, while higher performance WDXRF and EDXRF are best suited to measuring the trace elements too. Here are a few types of alloys that are commonly measured by XRF. a) Iron b) Steel - including low alloy and carbon Steel c) Stainless Steel d) Copper, brass, bronze, aluminum bronze, leaded brass and bronze e) Aluminum f) Nickel alloys - hastelloy, waspaloy g) Zinc alloys h) Cobalt alloys i) Titanium alloys j) Solders - tin, lead, and silver back to top Precious Metals Precious metals are also frequently analyzed by XRF. Gold carat weight determination in jewelry, ingots, and scrap is a common application. Other metals like platinum, and silver can also be analyzed by XRF. Precious metal ores, particularly gold ore have been measured by Ores, Slags, Feeds, Concentrates, and Tailings XRF plays a roll at each step of the metal making process. Major and minor components are analyzed with XRF instruments, and can even be measured on-line in many cases. Silicon Metal Silicon is an important metal in the semiconductor industry, and high purity is demanded. XRF is often used often used to monitor high silicon sands for impurities, and can be used throughout the refining process and through wafer production. Specialized high performance XRF equipment is designed for wafer analysis. Metal Foil Thickness There seems to be a use for foils made from every conceivable elemental metal. The thickness of thin foils can be measured by XRF, and this application can be done on line. back to Services |
