Jim Horst photographing
previously scanned gold
artifacts.
previously scanned gold
artifacts.
| The Science of Optically Stimulated Luminescence or Radiophotoluminecence (OSL) with comments on misconceptions and speculation on it's future by Jim Horst OSL is a technique of real and proven scientific value and an accurate method using modern scientific equipment and databases in evaluating and dating materials and artifacts. Those familiar with it are certainly aware the TL and OSL are proven and workable diagnostic scientific tools. Information about these techniques is available all over the Internet. Large scientific corporations, equipment manufacturers and software companies that manufacture and utilize this technology are in themselves testament to the workability of the science and techniques. The term Archaeochronometry refers to the whole complex of physical and chemical dating methods covering the period of the last two million years and applies to archaeological and geological problems. The field of age determination's multi sciences has been long proven and utilized in experimental research and should be viewed as the tools in the quest of scientific knowledge. It seems unjust that this truth is diluted with lies and the fear of reprisal arising from the exposure of fraudulent transactions, in effect making a true science seem a pseudoscience. Recently generated misinformation, intended to discredit the obvious workability of optically stimulated radiophotoluminescense in archaeology, has ignored and disregarded the historical record of its existence. What ends or goal is served to deny OSL technology? In the pursuit of true science, theory plays an important role; but realization of results occurs only after extensive testing, accurate empirical data acquisition, and positive final evaluations with similar repeatable positive results. There can be no allowances for consensus of uninformed beliefs. THERE IS NO PLACE IN SCIENCE FOR "WHAT DO OTHERS THINK". This will produce procedure clouded in doubt and commingle opinion with bad results. Only repeatable results count. TL or thermoluminescence is the emission of "cold" light in excess to the incandescent glow that occurs when a non-conductive solid is heated. It is caused by radiation damage having been accumulated in the crystal lattice. First discovered by Robert Boyle more than 300 years ago, in 1895 Wiedeemann and Schmidt discovered that it is induced by ionizing radiation. Daniels in 1953 discovered it could be used to enable age determination using minerals as natural TL dosimeters. Grogler found success in testing ceramics and bricks (Grogler et al.), and since "it has been firmly established in the fields of archaeology and geology during the 1960's and 1970's" (Wagner 1998). OSL or optically stimulated luminescence is closely related, also induced by radiation. The electrons are not thermally but optically stimulated. The electrons recombine at luminescence centers, and light is emitted as OSL. That light, the photoluminescence or radiophotoluminescence that is created, is what is measured and used in the determination of age. Several light spectra have been used in OSL including visual green, ultraviolet and infrared in the Raman and other spectral ranges. All things on earth and the universe are subject to radioactive exposure and decay. Radon, as an example, seems to be everywhere. Uranium and other radioactive elements are present in many sedimentary rocks such as the Permian flints. A layer of iridium identifies the Triassic boundary or KT. Also, the solar winds of gamma alpha x beta and other cosmic radioactive particles are constant though variable in intensity over time. This radiation exposure decay causes atomic decay. Some of these atomic decay particles get caught in crystalline lattice defect traps of atomic attraction. "If a solid with occupied electron traps and the potential to produce thermoluminescence is exposed to elevated temperature or and light, more or fewer electrons can escape from these traps according to the degree of activation and trap depth."(G. Wagner1998) These lattice defects (traps) are created over time, and logically the greater the content of the trap the greater the time element involved in its creation. All ceramics have a starting time clock or starting date of these traps creations, that being of the firing of said item. Firing from a later heating can reset the OSL clock starting it at the date of second firing. Stone's time clock can be set by the same method annealing (firing) or by flint knapping, exposing the protected (trap free) inner stone and pealing the cortex surface material that has been exposed to nuclear decomposition, erosion and lattice trap content building. Working bone and ivory even on ancient medium again peals the surface to reset the surface clock equal to the trap free subsurface. "Heated clay objects, such as kiln walls, mud linings of kilns, Burned clay remnants, and burned soil horizons can be treated analogously to ceramics for dating...The application of TL provides the date of the last heating (>400C)...The fact that kilns and hearths, unlike ceramic shards, frequently occur in situ, i.e. they still display their initial position as during firing, permits the application of archaeomagnetc dating. " (Wagner 1998). An example of this multi sciences approach to true age determination is exampled in the way C-14 dating was cross checked and confirmed with dendrochronology, or tree ring dating (Hedman 2007) If the spectrographic signature of a subsurface IR OSL scan is compared to a surface IR OSL scan of the same integration, time and intensity as the first, a comparison can be made after calculating the refraction. Comparisons of new measurements to existing libraries of scientifically created reference data OSL scans, of the same integration, time and intensity from like materials of known age allow conclusions as to the relevant age of the tested item to be derived from this scan data. An example of a comparison signature overlay IROSL scan readout is in fig. 1,2&3. Thermoluminescence has limitations in conductive metals but research has determined that OSL does not have this problem with conductors. Other data can be inferred from IROSL testing by segment analysis of the recorded signatures. Ceramic and stone objects can show high silica spikes to indicate heat-treating. Alloy humps in metals can indicate alloying in metals, and surfactant coating and repairs can be shown and localized. OSL is excellent for identifying before unrecognized repairs, coatings, stabilizers and fillers. Some surfactant coatings can cause an anomalous reading, it is obvious to an experienced technical operator that it these are indeed anomalous and usually are easily identified by their own signatures, even heavily coated items can be tested if untreated surfaces are available for sampling somewhere on the object of interest. Removal of the stabilizer or surfactant in an internal or unseen area can also be utilized to give a non-anomalous result. Fake surface patination may give the appearance of "old" in the visual light spectrum but will not change the rate of radioactive degradation, and therefore should not change the volume of energy in the lattice traps and should not alter data reading of the IR laser. I admit that little information or study has occurred in the field of, testing for, or creation of reproduction or fake subatomic disintegration lattice traps. Perhaps at present someone is trying to find a method of speedy high dose atomic decay for hire. And ye shall know the truth, and the truth shall set you free. (John 0001-0020) In the future the final evidence, demonstrated by extensive utilization of OSL in artifact authentication and its continued use and acceptance in archaeological contexts will be proof enough of its validity and worth. Until then, in the antiquities collection circles it's worth will probably be a continuing battle of scientific fact verses hearsay, of true data over flawed opinion and the exposure of the misuse of real data in unethical manners to defraud for monetary purposes. Though little conflict exists between true modern archaeology and OSL and other scientific age determining disciplines, huge problems exist with using them to authenticate large collections, though these are not flaws embedded in the science of OSL, instead they are political in nature. . If errors have been made in an IR testing all that needs to be done is simply retest the sample. Errors in antiquities acquisition result from critical mistakes made by institutional acquisition departments and private collectors alike. First, the best is desired and the primo pieces are usually unavailable or nonexistent. Therefore, these items have to be stolen (archaeologically misappropriated), forged or acquired at an extreme premium price. Most of the pieces acquired are of second hand nature and possess no true document al, provable provenance or archaeological association. Third, these acquired pieces of "old" art are not simply for the appreciation of the visiting viewer or collector but largely for the appreciation in their monetary value. Any negative test result will not act to appreciate said object, but instead will decrease it significantly. It is my "opinion" that many museums and top-end collectors are aware that many of the pieces in their collections are fakes. The museums and collectors do not want any more examination. It is not needed, as they know or suspect the truth and are simply using the piece as a beautiful reproduction on display. Leaving it in place therefore creates no need of replacement or cost to the collector or museum for this replacement. The piece looks good where it is. If it is found to be fake or even suspected to be, the value would be nil and the owner's rep would be compromised. Many chose not to be told the truth, and even when it may serve to reward them they hesitate, then fail to act due to the fear of failing. Great objects of believed antiquity in great institutions are at this moment screaming to be exposed for the knowledge distorting imitations that they are; yet their deceptions will likely not be exposed. Thankfully some of the enlightened administrators of these collections wish to sort the grain from the chaff and are actively turning to science to glean the fields. Those with honest intent should embrace any science that can bring some relief from the nightmare of fakery that has permeated the collector's world. Those who continue the path of larceny, and of false and greedy intent, in their course of creating fear distrust and deception in their attempt to discredit true science will ultimately fail, and eventually all will come to reckoning. Now is the new day. Embrace the quest for understanding and knowledge. "Come writers and critics who prophesize with your pen. And keep your eyes wide, the chance won't come again." (Dylan 1964) Grogler N, Houtermans FG, Stauffer H (1958) Radiation Damage as a research tool for geology and prehistory. Convegno sulle dotazioni con metodi nucleari.5\8powerRass. Internazion Elettr Nucli Sezione Nucleare Roma, pp5-15. Daniels F, Boyd CA, Saunders DF (1953) Thermoluminescence as a research tool Science 117:343-349 Wagner A, Gunther (1998) Age Determination of Young Rocks and Artifacts Physical and Chemical Clocks in Quaternary Geology and Archaeology Springer-Verlog Berlin Heidelberg TL OSL 7.17.3.3:219-285,2.7.7-2.7.9,42-45 Hedman Matthew (2007) The Age of Everything 71-73 John (1-20 A.D.) King James Bible 8:32 Dylon Bob, 1964 "The Times They Are a Changin' " Other topics: Internet Raman Spectroscopy Raman effect Raman scattering Archaeometry www.kosi.com www.lambdasolutions.com James (JIM) Horst Oracle I.R.OSL labs 401 N Sumner Beatrice NE 68310 mesoamer@windstream.net 402-520-1654 |