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Mössbauer and X-ray fluorescence measurements of authentic and counterfeited banknote pigments
Abstract
Mössbauer and X-ray fluorescence studies revealed that a number of valuable monetary units (dollars, pounds, yen, old German marks, and others) are printed using pigments which contain considerable amounts of iron. Mössbauer spectroscopy has been applied to the analysis of the pigments that are used in both authentic and counterfeit currency notes.
... As presented in Table 6, there are a variety of methods for identifying anti-counterfeiting features by extracting features related to brightness information [83,84], fluorescence characteristics [85][86][87][88][89][90][91][92], fidelity of the serial number and printing [93,94], and security threads [95]. Simple methods using only wavelengths of the visible light spectrum have limitations in accurately identifying anti-counterfeiting features. ...
... Simple methods using only wavelengths of the visible light spectrum have limitations in accurately identifying anti-counterfeiting features. Sensors with various spectral ranges to sense UV [85,86,96,97] and IR [75,82,[97][98][99][100][101] wavelengths, X-ray, [88] etc. are required. Table 6. ...
... Brightness information Y histogram of YIQ color space or luminance histogram [83,84] Fluorescence characteristics UV pattern [85][86][87] X-Ray fluorescence [88][89][90][91] Intrinsic fluorescence lifetime [92] Fidelity of serial number and printing Binarization, edge detection, and radial based function (RBF) NNs [93] Printing accuracy by tie point detection [94] Security thread Electromagnetic detection based on the pulsed eddy current technique [95] Infrared (IR) features ...
Despite a decrease in the use of currency due to the recent growth in the use of electronic financial transactions, real money transactions remain very important in the global market. While performing transactions with real money, touching and counting notes by hand, is still a common practice in daily life, various types of automated machines, such as ATMs and banknote counters, are essential for large-scale and safe transactions. This paper presents studies that have been conducted in four major areas of research (banknote recognition, counterfeit banknote detection, serial number recognition, and fitness classification) in the accurate banknote recognition field by various sensors in such automated machines, and describes the advantages and drawbacks of the methods presented in those studies. While to a limited extent some surveys have been presented in previous studies in the areas of banknote recognition or counterfeit banknote recognition, this paper is the first of its kind to review all four areas. Techniques used in each of the four areas recognize banknote information (denomination, serial number, authenticity, and physical condition) based on image or sensor data, and are actually applied to banknote processing machines across the world. This study also describes the technological challenges faced by such banknote recognition techniques and presents future directions of research to overcome them.
... Previous works based on imaging sensors with wavelengths outside the visible light range mostly focused on capturing the security features, such as latent patterns on Korean [9] and Indian [10] banknotes under UV light, or dark and bright areas on Euro banknotes [6] under IR light. X-rays were also considered for counterfeit coin detection [11], [12] and banknote pigment-based counterfeit detection in [13]. Because the security features are located at certain positions on banknotes, these counterfeit detection methods assumed that either the denomination and input direction of banknotes are known or the pre-recognition of the banknote type is required. ...
... -We make our trained CNN models and algorithm available to other researchers through a report [21] for comparison with our method. -Using X-rays for pigment-based fakebanknote detection [13]. ...
Automatic recognition of fake banknotes is an important task in practical banknote handling. Research on this task has mostly involved methods applied to automatic sorting machines with multiple imaging sensors or that use specialized sensors for capturing banknote images in various light wavelengths. These approaches can make use of the security features on banknotes for counterfeit detection. However, they require specialized devices, which are not always available for general users or visually impaired people. Meanwhile, smartphones are becoming more popular and can be useful imaging devices. Moreover, the types of fake banknotes created by imaging devices such as smartphone cameras or scanners are sometimes cannot be recognized by especially the visually impaired people. Addressing these problems, we propose a method for classifying fake and genuine banknotes using visible-light images captured by smartphone cameras based on convolutional neural networks. Experimental results on a self-collected dataset of US dollar, Euro, Korean won, and Jordanian dinar banknotes showed that our method performs better in terms of fake detection than the state-of-the-art methods.
... Some researchers proposed to analyse the ink composition to distinguish legitimate banknotes from counterfeits. Rusanov et al. [20] applied Mössbauer spectroscopy to analyse the chemical composition of the ink used in both genuine and counterfeit banknotes. They examined 54 authentic $100 US banknotes chosen at random, and 13 forged notes which were provided by a bank in Bulgaria. ...
Polymer banknotes are the trend for printed currency and have been adopted by more than fifty countries worldwide. However, over the past years, the quantity of polymer counterfeits has been increasing, so has the quality of counterfeits. This shows that the initial advantage of bringing a new polymer technology to fight against counterfeiting is reducing. To maintain one step ahead of counterfeiters, we propose a novel anti-counterfeiting technique called Polymer Substrate Fingerprinting (PSF). Our technique is built based on the observation that the opacity coating, a critical step during the production of polymer notes, is a stochastic manufacturing process, leaving uneven thickness in the coating layer and the random dispersion of impurities from the ink. The imperfections in the coating layer result in random translucent patterns when a polymer banknote is back-lit by a light source. We show these patterns can be reliably captured by a commodity negative-film scanner and processed into a compact fingerprint to uniquely identify each banknote. Using an extensive dataset of 6,200 sample images collected from 340 UK banknotes, we show that our method can reliably authenticate banknotes, and is robust against rough daily handling of banknotes. Furthermore, we show the extracted fingerprints contain around 900 bits of entropy, which makes it extremely scalable to identify every polymer note circulated globally. As compared with previous or existing anti-counterfeiting mechanisms for banknotes, our method has a distinctive advantage: it ensures that even in the extreme case when counterfeiters have procured the same printing equipment and ink as used by a legitimate government, counterfeiting banknotes remains infeasible because of the difficulty to replicate a stochastic manufacturing process.
... Pigments used in various fields can also be analyzed using Mössbauer spectroscopy, examples of which include studies on pigments in mural painting for the preservation of historical artwork and those on banknotes for the discrimination of counterfeit banknotes from authentic ones [11]- [13]. ...
An X-ray fluorescence (XRF) imaging system was developed to analyze various materials based on characteristic X-rays emitted from objects exposed to X-ray flux. The XRF system can be used in various industrial fields, such as nuclear fuel analysis to guarantee combustion stability in the nuclear reactor, glazed material analysis to preserve and restore ceramic cultural assets, impurity measurements in electronic circuits, etc. In this study, we built an XRF imaging system and performed several material analyses using a look-up table, which contained energy and channel information of the characteristic X-ray peaks of each element. Ceramic specimens coated in various glazes were analyzed and imaged for oriental pottery research. Pigments of various colors were also analyzed and imaged for picture assessment, as were electronic circuits and gold plates. Ceramic, pigment, and metal components in the samples were discriminated by comparing characteristic X-ray peak data on the look-up table. Two-dimensional material images, which showed the material distribution of each sample, were successfully obtained.
... This method allows not only experienced scientists in laboratories, but also bank employees, police personnel, and shop workers to identify forged banknotes [16]. Mössbauer spectroscopy has been applied to the analysis of pigments in authentic and counterfeit banknotes [17]. The former contain relatively larger amounts of iron, so the detection of counterfeits is possible. ...
In this study, two very promising techniques, micro X-ray fluorescence (μXRF) and laser-induced breakdown spectroscopy (LIBS) were applied to the examination of Polish banknotes – Polish zloty (zl).
Several areas on each banknote were selected and analysed. Different elemental compositions were identified after comparing the spectra recorded from various measurement locations. It was possible to identify characteristic atomic emissions from one or several elements such as Ca, Ti, Fe, Ba, Co, Cr, Cu, Mg, Mn, Ni, V, and Zr, depending on the banknote denomination, issue date, and evaluated spot. Potentially good discriminators with unique elemental composition were identified: black serial number (C) and microlettering (A). A comparison of brand-new banknotes with used banknotes (which have been in circulation) was also performed. The middle horizontal section of the banknotes shows higher exposure to contamination and consequently constitutes the most difficult part to analyse. Counterfeit banknotes were also analysed and were clearly distinguished from authentic notes in all cases. It was demonstrated that a comparison of the elemental composition is a useful way to detect counterfeit banknotes (10, 20, 50 and 100 zl) in ‘real-world’ cases.
This study shows the potential of LIBS and μXRF as effective and practical techniques to analyse Polish banknotes. Their many advantages provide a good alternative to the analytical methods routinely used for the examination of these objects.
... The concentration of pigments in the printer ink used and the specificity of their Mössbauer spectra can be used to identify fakes and forgeries [62]. Same authors showed that Mössbauerr and X-ray fluorescence studies revealed that a significant number of banknotes are printed using pigments which contain considerable amounts of iron [63]. ...
Counterfeiting and piracy are a form of theft that has been steadily growing in recent years. Banknotes and identity documents are two common objects of counterfeiting. Aiming to detect these counterfeits, the present survey covers a wide range of anti-counterfeiting security features, categorizing them into three components: security substrate, security inks and security printing. respectively. From the computer vision perspective, we present works in the literature covering these three categories. Other topics, such as history of counterfeiting, effects on society and document experts, counterfeiter types of attacks, trends among others are covered. Therefore, from non-experienced to professionals in security documents, can be introduced or deepen its knowledge in anti-counterfeiting measures.
... Since, the fake notes are crime evidence, their integrity must be preserved, so the use of nondestructive techniques is ideal for this type of analysis. Several recently published papers have presented different techniques for discrimination of genuine and counterfeit banknotes, such as, X-ray fluorescence [3,7,8], mass spectrometry [9][10][11][12], Raman, near-infrared [13] and mid-infrared spectroscopies [14][15][16]. The use of portable instruments for forensic analysis in particular, has been increasing significantly [17]. ...
As technology advances, counterfeiters improve their techniques reproducing banknotes with more accuracy. Spectroscopic techniques may be applied for characterization of these forgeries. The aim of this study was to develop a methodology for banknotes characterization employing portable X-ray fluorescence (pXRF) and portable Raman spectroscopy (RS) equipment for measurements in genuine and counterfeit Real (Brazilian currency) banknotes. Quantification of the metals in the ink and paper was carried out with pXRF data, using a sensitivity curve. pXRF spectral analysis was effective to discriminate between genuine and counterfeit bills. Moreover, the quantification of the metals enriched the analysis, since it was possible to compare elements concentration that are commonly found in genuine and counterfeit banknotes. The use of partial least square discriminant analysis (PLS-DA) applied to pXRF data was efficacious to identify fake banknotes and it may be used for further investigation about the provenance of forgeries. Principal component analysis (PCA) grouped forgeries from different seizures based on similarities in the elemental composition. The spectra obtained by RS allowed identification of characteristic bands of two pigments from the inks: phthalocyanine and diarylide. For the RS data, PLS-DA and PCA successfully discriminated R$ 50 genuine and fake banknotes.
... As currencies counterfeit have become increasingly sophisticated as well as the ability of the forgers to fraud the available authenticity techniques, the development of more reliable exams, especially those based on chemical information has become relevant. Previously, chemical information has been used to identify counterfeit banknotes with different analytical techniques, such as, laser-induced IR photothermal radiometry [4], X-ray fluorescence [5,6], mass spectrometry [7][8][9][10], Raman [11,12] midinfrared [13][14][15] and near-infrared [16] spectroscopies. ...
Spectra recorded using a portable near infrared (NIR) spectrometer, Soft Independent Modeling of Class Analogy (SIMCA) and Linear Discriminant Analysis (LDA) associated to Successive Projections Algorithm (SPA) models were applied to identify counterfeit and authentic Brazilian Real (R50 and R20, R100 currencies. These results show that the use of the portable near-infrared with SIMCA or SPA-LDA models can be a completely effective, fast, and non-destructive way to identify authenticity of banknotes as well as permitting field analysis.
... Falsification of currency banknotes is a frequent illegal activity. The falsification of Dollars (CNBC, 2016;Reuters NBC News, 2016;Rusanov et al., 2009), Euros (Cabitza, 2012;Europol, 2012) and other currencies has forced governments to elaborate ever more sophisticated security features (Dwan, 2002), as for example, the development of microprinting, the use of fluorescent inks, plastic paper and the use of substances reactive against UV and IR, among others. In Peru, the latest false banknotes are very difficult to identify for most people (Franklin, 2016) because falsifiers can reproduce many of the security features established by Peru's Central Reserve Bank (BCRP) as are fluorescent images under UV light and chalcographic marks for touch recognition (BCRP, 2016). ...
The aim of this study was to verify if a portable X-ray fluorescence (pXRF) spectrometer can recognize the security features in banknotes that are reproducible by counterfeiters. Peruvian Nuevo Sol banknotes were studied: 4 genuine and 3 fake ones, in 11 points of analysis for each one, at all 77 data set. The correlation analysis of spectra among original notes was 1.0, and there was no correlation with fake banknotes. pXRF prove that two security features were reproducible for counterfeiters.
... In forensic science and in the specific field of banknote counterfeiting or questioned documents, different analytical techniques are employed (2). Chemical fingerprinting or more specific ink analysis is frequently suggested as a tool for discrimination and identification of the samples for forensic purposes, using RAMAN (3)(4)(5)(6)(7)(8)(9)(10), IR (11)(12)(13)(14), Mossbauer (15), X-ray fluorescence spectroscopy (11,15,16), and mass spectrometry (including electrospray ionization, secondary ion mass spectrometry, laser-based methods, and ambient ionization methods) (10,(17)(18)(19)(20)(21)(22). In particular, some articles report about analysis of paper sheet samples for cultural heritage conservation or for forensic purposes performed with different analytical methods (IR [23][24][25] and UV-vis-NIR spectroscopy [26], mass spectrometry [27][28][29], energy-dispersive X-ray analysis [30,31], X-ray diffraction [23,32], light transmission images [33], and scanning electron microscopy [34]). ...
We report about the X-ray powder diffraction characterization of crystalline materials used to produce genuine and counterfeit banknotes, performed with a single-crystal diffractometer that permits fast and nondestructive measurements in different 0.5-mm sized areas; 20-euro denomination genuine banknotes were analyzed, and results were compared with counterfeit banknotes. The analysis shows that the papers used to print real banknotes are composed, as expected, of cotton-based cellulose and titanium dioxide as crystalline additive, but different polymorphs of TiO2 for different emission countries are evidenced. The counterfeit banknotes are composed of cellulose based on wood pulp; moreover, an unexpected significant quantity of TiO2 was found to be mixed with calcite, indicating that the paper employed by forgers is not simply a common low-cost type. The crystalline index and intensity ratios between the peaks attributable to cellulose and fillers can provide additional information to trace back paper suppliers for forensic purposes.
... This method makes use of a compact Fourier transform infrared spectrometer (FT-IR). Moreover, Mö ssbauer and X-ray fluorescence have been presented as useful tools for the analysis of pigments in authentic and counterfeit US dollar and Euro banknotes [12]. The potential of portable X-ray fluorescence (PXRF) spectrometry supported by principal component analysis (PCA) has been confirmed after the rapid and nondestructive examination of different colored regions of US dollar, Euro and Real banknotes [13]. ...
The identification of forged and genuine historical banknotes is an important problem for private collectors and researchers responsible for the care of numismatic collections. This paper presents a research approach for detecting material differences in historical banknotes through the use of microfading spectrometry along with other techniques such as hyperspectral image analysis, Fourier-transform infrared spectroscopy, and X-ray fluorescence spectrometry. Microfading spectrometry results showed higher sensitivity to light irradiation for an overprint ink used on a suspicious banknote relative to its counterparts. In addition, the spectrocolorimetric changes experienced by the paper substrates during microfade testing also provided a way for discriminating between two groups of banknotes. These variations have been confirmed after analyzing the spectral and physico-chemical data obtained using the abovementioned complementary techniques.
... To date, diverse analytic methodologies have been applied. For example, FTIR [2] has been applied to analyze Japanese passports and Mossbauer and X-ray fluorescence [3], ATR-infrared spectroscopy [4] and Raman spectroscopy [5] [6] have been used to analyze banknotes. All such tools are non-destructive and cheap forensic approaches, particularly when chemometrics tools are used [7]; however, instrumental operations requirements and data processing may make the spectroscopic application in questioned documents analysis complex. ...
Fast and unequivocal methods of questioned document analysis are essential in forensic science. Here, a desorption/ionization technique, EASI-MS, was assessed for its ability to investigate questioned driver’s licenses (DL). Two suspects DL, displaying the same personal data in the proper fields (name and ID numbers), but with different individual photos, showing similar impressions on microscopic analysis, and authentic standards documents specimens were used as test cases. Profiles from authentic DL surface were dominated by a set of few minor ions, mainly from the plasticizers bis(2-ethylhexyl)phthalate and dibutylphthalate. The seized suspect counterfeit DL on points from personal data and photo were, however, dominated by abundant diagnostic ions of m/z 463, 507, 551, 595, 639, 683, which confirmed counterfeiting. Surfynol® and Nonoxynol-9®, which are common constituents of inkjet printing, were detected in the counterfeiting areas by high-accuracy EASI(+)-FT-ICR MS. The EASI-MS technique is shown therefore to offer an attractive tool for forensic investigation of questioned documents.
... Mössbauer spectroscopy is a nondestructive alternative method to determining the atomic composition of pigments [9]. It is found, the black ink on US banknotes is more stable than green, black has very stable structure that is high in iron whilst green is more erratic. ...
By its definition, the word ‘currency’ refers to an agreed medium for exchange, a nation’s currency is the formal medium enforced by the elected governing entity. Throughout history, issuers have faced one common threat: counterfeiting. Despite technological advancements, overcoming counterfeit production remains a distant future. Scientific determination of authenticity requires a deep understanding of the raw materials and manufacturing processes involved. This survey serves as a synthesis of the current literature to understand the technology and the mechanics involved in currency manufacture and security, whilst identifying gaps in the current literature. Ultimately, a robust currency is desired.
... Black dots-counterfeit 100 USD old bill, blue dotscounterfeit 100 USD new bill, and cyan dotscounterfeit 50 USD new bill. Authentic and counterfeit bank notes with similar parameters are marked with a red line[4]. ...
The 100 USD Federal Reserve Notes (FRN) are most frequently falsified. The so-called "super hundreds" or "super dollars" are "very high quality" false bank notes printed on Giori presses by the intaglio method with iron-bearing pigments similar to those used by the Bureau of Engraving and Printing (BEP) in Washington DC. To avoid further problems the BEP released enormous quantities of newly designed 100 USDs. However, the new design was immediately counterfeited, too. Soon, the new design of the 50 USD was also counterfeited (Fig. 1). A large number of authentic and counterfeit USD bank notes were studied by means of two experimental techniques: Mössbauer spectroscopy and Energy Dispersive X-Ray Fluorescence (EDXRF) analysis [1-4]. One example and the summary of all Mössbauer results obtained are present in Fig. 1. Our HASYLAB project include EDXRF investigations at an excitation energy of 20 keV of micro areas on the counterfeited bank note surface, covered by one color only and with one layer of paper only, and XANES analysis of the Fe K-edge, which is sensitive to the oxidation state of 3d-transition metals. The experimental setup of Beamline L offers the necessary equipment for these experiments. The multi element trace analysis may answer the forensic question: did the forgeries have one and the same source of dissemination? The X-Ray spectroscopy, XANES and the Mössbauer measurements have been analyzed in parallel. Figure 1: (top) Mössbauer spectrum obtained at room temperature from a single counterfeit 50 USD bank note; (center) photograph of the newly designed counterfeited 50 USD bank note from which the Mössbauer spectrum was obtained; (bottom) distribution of Mössbauer parameters of all bank notes measured in a coordinate system with the following three axes: first-line area ratio of the B-and A-sites sextets in magnetite I B /I A ; area ratio between the first line of the green dye sextet and the first line of the A-sites sextet in magnetite I G /I A ; and ratio of the experimental line widths for the first lines of the B-and A-sites of magnetite Γ B /Γ A . Red dots -genuine 100 USD issued between 1934 and 1993 (without the issue of 1990), green dots -genuine 100 USD issued 1990, and the boundary of the 1990 sample is marked with a green line. Black dots-counterfeit 100 USD old bill, blue dots -counterfeit 100 USD new bill, and cyan dots -counterfeit 50 USD new bill. Authentic and counterfeit bank notes with similar parameters are marked with a red line [4]. Fe 3+ Fe 3 O 4 Fe 3 O 4 B-sites Transmission Velocity, mm/s A-sites First we want to address to the EDXRF analysis of the paper used for printing USD bills, because in the earlier studies the blank paper was not studied by means of Mössbauer spectroscopy. The paper used for printing counterfeited old 100 USD bank notes contain as a whitening and filling agent only TiO 2 (Fig.2 a). For the printing of counterfeited new 100 USD and counterfeited new 50 USD bank notes mixtures of TiO 2 and a calcium compound, probably CaCO 3 , in specific ratios are used (Fig. 2 b, c). Fig. 2 d presents the element composition of the paper used in simple forgeries printed without any iron-bearing pigments. Here the main element is Ca. These specificities are typical for the whole group. Every single group has specific trace elements presented as impurities in TiO 2 , i. e. in the third group they are Fe, Cu, Zn, Y (main), Zr and Nb (Fig. 2 c). Figure 2: EDXRF analysis of paper used by the printing of different groups of counterfeited USD bank notes. The explanation is given in the text. The "high quality" forgeries are printed with magnetite Fe 3 O 4 black dye. The Mössbauer spectro-scopy measurements (Fig. 1) provide evidence for one and the same source of dissemination. Large variations in the chemical composition of the green printing inks are detected. Simple green pigment, PbSO 4 ⋅xPbCrO 4 ⋅yFe 4 [Fe(CN) 6 ] [5] or chemically pure chrome green, Cr 2 O 3 was identified. Figure 3: Mössbauer spectra obtained at 130 K and XANES results obtained at room temperature (inset) from two different black-day pigments show very different and specific Fe 3+ /Fe 2+ ratio. The Mössbauer and XANES studies confirm that magnetite pigments are always very specific (Fig. 3), they are used to faint 14 counterfeited bank notes printed in different years, with nearly always the same Fe 3+ /Fe 2+ ratio, which is incredible. The results from the EDXRF analysis of the blank paper and of the black and green pigment are very similar and confirm the classification of the group of counterfeited bank notes. This is an additional argument that if not all counterfeited bank notes or dyes have the same source of dissemination, then at least they have been prepared using quite similar constituents.
... In forensic science and in the specific field of questioned documents, banknote counterfeiting analyses for many different bills from several countries have been performed, applying diverse analytic methodologies. Mossbauer and Xray fluorescence [2], ATR-infrared spectroscopy [3] and Raman spectroscopy [4,5] have constituted a set of interesting non-destructive forensic analyses; however, processing the amount of data acquired with similar spectroscopic methods for counterfeit and genuine banknotes requires the use of chemometrics tools [6]. The use of gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/ mass spectrometry (LC/MS) to characterize the ink composition of banknotes has been reported [7][8][9][10][11], but the pretreatment procedures required for GC/MS and LC/MS are usually time-consuming and may result in irreparable damage to the banknotes, which is not useful for forensic sample preservation [12]. ...
Using a desorption/ionization technique, easy ambient sonic-spray ionization coupled to mass spectrometry (EASI-MS), documents related to the 2nd generation of Brazilian Real currency (R. The seized suspect counterfeit banknotes, however, displayed abundant diagnostic ions in the m/z 400–800 range due to the presence of oligomers. High-accuracy FT-ICR MS analysis enabled molecular formula assignment for each ion. The ions were separated by 44 m/z, which enabled their characterization as Surfynol® 4XX (S4XX, XX = 40, 65, and 85), wherein increasing XX values indicate increasing amounts of ethoxylation on a backbone of 2,4,7,9-tetramethyl-5-decyne-4,7-diol (Surfynol® 104). Sodiated triethylene glycol monobutyl ether (TBG) of m/z 229 (C10H22O4Na) was also identified in the seized counterfeit banknotes via EASI(+) FT-ICR MS. Surfynol® and TBG are constituents of inks used for inkjet printing.
Counterfeiting or forged imitation of banknotes is a perpetual practice engulfing global economies. This not only poses challenges for the material scientists to come forth with advanced security materials but also demands veracious forensic examination to detect counterfeits. The present article pursues novel efforts in summarizing a study that lays focus on the recent optical and analytical examinations being used for the characterization and detection of chemical profiles of authentic and counterfeited banknotes. The article briefs the trends in banknote materials, security paper manufacturing process, security inks used for printing, and types of the security printing process in banknote practices. Reported literature shows the introduction of new anti-counterfeiting materials viz. magnetically-responsive photonic anti-counterfeiting watermarks, and fluorescent nanoparticles that can be used as anti-counterfeiting inks, anti-stokes inks, metameric inks, etc. Analytical techniques such as IR spectroscopy, Raman spectroscopy, Mossbauer spectroscopy, X-ray diffraction, X-ray fluorescence, LIBS, XRF, ELDI-MS, EASI/DESI-MS, HPLC, VSC, AFM, etc. in conjunction with different chemometrics approaches have been critically discussed. The study also presents the future scope in banknote examination like the use of hyper spectral imaging and sensor-based counterfeit detection systems.
Counterfeiting of banknotes remains a severe threat to economic security and social stability. The characterization of banknote has mainly relied on the assessment of various security features applied to the surface of the note. However, the surface features are easy to forge and contain insufficient information to discover the source. In this paper, a novel approach for banknote characterization has been proposed by employing spectral‐domain optical coherence tomography (SD‐OCT) that can provide structural and optical features. Three groups of counterfeit Chinese 100 Yuan banknotes produced by different printing manners and one group of authentic banknotes were examined by SD‐OCT without any sample preparation and four distinct areas were selected for imaging. High‐resolution tomographic and three‐dimensional (3D) volumetric OCT images were obtained and a set of features were first revealed to characterize the banknotes qualitatively and quantitatively. The results demonstrated that SD‐OCT was effective to detect and classify different types of counterfeit banknotes and could potentially be used to link counterfeit banknotes to their sources in a fast, simple and nondestructive manner.
An X-ray fluorescence (XRF) imaging system is a material analysis system that can represent the material distribution and types of elements by detecting characteristic X-rays emitted from each element. A CdTe semiconductor detector array whose detection efficiency is significantly higher than a silicon drift detector (SDD) is utilized with a deep learning method to improve the energy spectral analysis. In this study, deep learning models for material discrimination and quantitation were applied based on 20 000 energy spectra obtained from Fe, Ni, Cu, and Zn rod phantoms, and a brass phantom was analyzed to verify that Cu, Zn, and brass can be distinguished from each other and that the amount of Cu and Zn in each phantom can be quantitatively analyzed.
Analytical Archaeometry describes this interesting and challenging field of research - on the border between natural sciences (chemistry, spectroscopy, biology, geology) and humanities (archaeology, (art-)history, conservation sciences). It fills the gap between these two areas whilst focussing on the analytical aspects of this research field. The first part of the book studies the main analytical techniques used in this research field. The second part expands from the different types of materials usually encountered, and the final part is organised around a series of typical research questions. The book is not only focussed on archaeological materials, but is also accessible to a broader lay audience. Overall the book is clearly structured and gives insight into different approaches to the study of analytical providing extensive discussion on a wide range of techniques, materials, questions and applications. Due to the advances in analytical instrumentation and applications in this field, it is important to have all this information merged together. Academics as well as professionals in archaeology, art history, museum labs and conservation science will find this an invaluable reference source ensuring the reader is provided with the latest progress in this research field.
Polymer banknotes are the trend for printed currency and have been adopted by more than fifty countries worldwide. However, over the past years, the quantity and the quality of polymer counterfeits have been increasing. This shows that the initial advantage of bringing a new polymer technology to fight against counterfeiting is reducing. To maintain one step ahead of counterfeiters, we propose a novel anti-counterfeiting technique called Polymer Substrate Fingerprinting (PSF). Our technique is built based on the observation that the opacity coating, a critical step during the production of polymer notes, is a stochastic manufacturing process, leaving uneven thickness in the coating layer and the random dispersion of impurities from the ink. The imperfections in the coating layer result in random translucent patterns when a polymer banknote is back-lit by a light source. We show these patterns can be reliably captured by a commodity negative-film scanner and processed into a compact fingerprint to uniquely identify each banknote. Using an extensive dataset of 6,200 sample images collected from 340 UK banknotes, we show that our method can reliably authenticate banknotes, and is robust against rough daily handling of banknotes. Furthermore, we show the extracted fingerprints contain around 900 bits of entropy, which makes it highly scalable to identify every polymer note circulated globally. As compared with previous or existing anti-counterfeiting mechanisms for polymer banknotes, our method has a distinctive advantage: it ensures that even in the extreme case when counterfeiters have procured the same printing equipment and ink as used by a legitimate government, counterfeiting banknotes remains infeasible because of the difficulty to replicate a stochastic manufacturing process.
Paper and paper products banknotes play an important role in daily life. Two terahertz (THz) time-domain spectrometers (TDS) with combined spectral coverage from 0.5 to 10 THz were used to characterize the optical properties of several types of paper and banknotes. We found that the paper and banknotes show remarkable fingerprints in the terahertz regime, which are highly related to the vibrational modes of the main component of paper and banknotes — celluloses. Meanwhile, THz transmission imaging measurements had been performed and shown the capability of imaging the key anti-counterfeit labels of banknotes such as watermarks, security threads and optically variable inks. The presented study here indicates that the THz spectroscopy together with the imaging method could provide a visible, contactless and nondestructive alternative to delineating paper and paper product banknotes.
The development of science and technology brings new tools to improve security features on banknotes as well as methods to verify their authenticity. This development also expands the technical possibilities for money counterfeiting. The paper deals with the experimental examination of selected protective elements - paper and inks used on euro banknotes. The advanced analytical method Raman spectroscopy was used for experimental analysis, as method meets the requirements crucial for forensic examination. The main aim is to obtain characteristic Raman spectra of selected security features that can serve for testing the authenticity of questioned banknotes. The results show an apparent diversity of spectral markers in individual samples and the method suitability for the authentication. A comparison of the results for euro banknotes of the first and the Europa series is discussed in the paper.
Forensic science is an emerging field driven by a number of factors, and the development of different methods of analyses, instruments, and techniques is of great help to experts in the field. Sampling and sample preparation in forensic cases are of utmost importance, and therefore, the methods for processing (or not) the samples are critical for acquiring accurate results. Some alternatives for attaining the minimalist concept, i.e. little or no sample treatment, are discussed in this review. For elemental analysis, analytical techniques, such as X-ray spectrometry, laser-ablation mass spectrometry, laser-induced breakdown spectrometry, inductively coupled plasma mass spectrometry and optical emission spectrometry, and Mössbauer spectrometry are overviewed. Molecular analysis, such as Raman spectroscopy, and ambient ionization mass spectrometry are discussed. Some representative examples are presented that involve in situ analysis, counterfeit bank notes and documents, post-mortem and bone analyses, and forensic analysis of drugs, glass, fingerprints, biological fluids and explosives.
Electrospray laser desorption ionization mass spectrometry (ELDI/MS) was used to rapidly distinguish authentic banknotes from counterfeits of the US dollar and the New Taiwan dollar. The banknotes' surfaces were irradiated with a pulsed ultraviolet laser, after which the desorbed ink compounds entered an electrospray plume and formed ions via interactions with charged solvent species. Authentic banknotes were found to differ from their counterfeit equivalents in their surface chemical compositions. The detected chemical compounds included various polymers, plasticizers and inks; these results were comparable with those obtained using solvent extraction followed by electrospray ionization mass spectrometry analysis. Because of the high spatial resolution of the laser beam, ELDI/MS analysis resulted in minimal damage to the banknotes. Copyright © 2013 John Wiley & Sons, Ltd.
Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400cm(-1) arising from νasym (CO3(2-)) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ν(OH) (ca. 3500cm(-1)), ν(CH) (ca. 2900cm(-1)) and ν(CO) (ca. 1750cm(-1)) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper.
In this paper, monodisperse 6 nm-sized Fe3O4 nanoparticles with spinel crystalline structure were synthesized via a co-precipitation method. The effect of HCl concentrations
on Fe3O4 samples was investigated by TEM, VSM and UV–vis. HCl-modified Fe3O4 nanoparticles solution was a stable, clear, transparent cationic colloid. The results showed that HCl had a great influence
on the dispersity of Fe3O4 nanoparticles and almost no influence on the materials magnetism.
To evaluate the effectiveness of Raman microspectroscopy in euro banknotes’ recognition, several genuine and fake 10 and 20 euro banknotes were analyzed. Raman microspectroscopy revealed itself to be very useful in the detection of differences in the inks used to provide the color on the banknotes. However, the study revealed that the Raman analysis results are not decisive to guarantee the authenticity of a specific banknote since similar Raman spectra were obtained for genuine and fake banknotes. Even the Raman microspectroscopy analysis obtained for the same color on different areas of fake banknotes revealed similar spectra, and this can help law enforcement agencies to identify counterfeit tracking routes.
This comprehensive review covers the latest published activities using XRF techniques. X-ray analytical equipment continues to be integrated with X-ray emission/diffraction/absorption techniques with the growing use of synchrotron radiation (SR) sources reflected in the literature. This integration trend was also prevalent in the development of small-scale laboratory equipment. X-ray detectors have advanced with pixellated systems, micro-calorimeter types and the now established silicon drift detectors being readily used by many authors. Matrix correction and calibration procedures have developed to accommodate instrumental developments related to micro-beam and bulk analysis. SR-based micro-techniques for two and three dimensional imaging were reported in research activities in applications for clinical, biological, environmental and cultural heritage studies as well as investigations of extraterrestrial material. Sample preparation developments continue, especially for TXRF. The extension of TXRF to measure the angle dependence fluorescence signal (GI-XRF, XSW) showed increased interest with several groups applying the technique to depth profiling and thin layer analysis of nano-particles. More applications were reported this year for the reversed technique (GE-XRF) combining micro-beam analysis with surface sensitivity. Geochemical mapping of the moon is reported after space flight measurements used the Sun as a radiation source. The literature reflects increasing quantitative analysis using portable XRF with a welcomed growth in acceptance by the Food and Drug authorities and other applied users. This year's Update offers dietary delights for those who enjoy crab meat and an insight into the eating habits of elephants. Advice for gardeners contemplating a green roof is reported along with analysis of the wood treatments used in the manufacture of Stradivari and Guarneri violins. XRF has also played its part in the development of self-cleaning fabrics.
Some newly discovered effects lose their glamor after a short period of euphoria. Others, however, retain their fascination for a long time and, even as they mature, display unexpected features. The Mossbauer effect belongs to the second category. Rudolf Mossbauer's discovery of recoilless gamma-ray emission in 1957 immediately caused a flurry of attention, and confirming work appeared almost at once. Since then the flow of publications has steadily increased. Most studies follow predict abl e paths; the essential aspects of these "conventional" experiments have been described in the first volume of the present work (Mossbauer Spectroscopy, Topics in Applied Physics, Vol. 5). These straightforward investigations have not, however, exhausted the field, boredom has not set in, and unexpected applications continue to appear. In the present volume, Uli Gonser has collected contributions that display the "exotic" side of the Mossbauer effect. They range from a masterly de scription of the red-shift experiment to a clear exposition of a powerful solution to the old and painful phase problem in crystallography. Each of the contributions exhibits a different side of recoilless gamma-ray emission. Together they show that the field is very much alive and continues to delight us with elegant solutions to old problems, unanticipated glimpses at new phenomena, clever uses of new technical possibilities, and ingenious applications to fields far away from physics. I believe that novel features of the Mossbauer effect will continue to appear and that new applications will still be found.
The SYnchrotron X-Ray Fluorescence analysis (SYXRF) is a powerful tool for the analytical determination of trace element concentrations. By using synchrotron radiation instead of an X-ray tube, the sensitivity of the XRF method is greatly enhanced. This is due to the high intensity, spectral distribution, beam collimation and to background reduction by polarization effects. Excitation with the white spectrum as well as monoenergetic excitation are possible, which has significant influence on the obtained physical detection limits. Quantification of the results is possible by applying different models, including the recently developed Monte-Carlo simulation technique. Microbeam analysis is possible by collimating and focusing the beam to a spot size in the urn range. By use of the recently developed capillary optics, an intensity gain can be achieved even for small beam sizes. The SYXRF method is presently used in numerous application fields, including geoscience, material sciences, biology, and examination of historical artefacts.
In a book with the subtitle “the exotic side of the method” it seems quite appropriate to discuss and explore some odd and strange examples in a separate chapter. Among the wide range of applications found for the Mössbauer effect are a number that are funny or sophisticated or strange or surprising. Such adjectives might be applied to the methods used, the subject investigated, or the results obtained. In this chapter we describe some applications that made a special appeal to our sense of the exotic.
The calculation of Lang2) for interpreting Mössbauer spectrum areas is extended to larger values of absorber thickness. The results are presented graphically together with values of the absorption amplitude and relative line width calculated by Roberts and Thomson3).
Energy dispersive X-ray fluorescence (EDXRF) was used to nondestructively determine the elemental composition of current-size $10 United States Federal Reserve Notes (FRN) from series 1928 to series 2003. The X-ray spectra from all the bank notes were cataloged into a digital spectral library for searching and comparisons of questioned bank notes. Paper and different color printing inks were analyzed to determine elemental composition. One of the components of the green ink on the back of the early issues was identified as being the compound pigment Pigment Green 15, also known as chrome green (PbSO4·xPbCrO4·yFe4 [Fe(CN)6]) precipitated onto a base of baryte (BaSO4) and Paris white (CaCO3). Our data show that the concentrations of Pb in the green ink have declined since the first issue of Series 1928 and ended with Series 1988. EDXRF is an excellent analytical method for rapid nondestructive elemental analysis of bank notes. This elemental characterization is useful for authenticating bank notes for the numismatist and for the forensic scientist. The method described can also be used for quality control in the manufacture of bank notes and for evaluating how circulating bank notes deteriorate.
Two groups of "high quality" counterfeit United States currency bank notes from the old and new 100 USD bank note bill, respectively, are investigated by means of Mössbauer spectroscopy, and their Mössbauer parameters are compared to genuine 100 USD bank note parameters. The dispersion of the distribution of the Mössbauer parameter values for 54 genuine bank notes is discussed. The most unstable spectra appear to be those of the green pigment. The instability of pigment properties is due to the different thermal conditions at which the different manufacturers have synthesized the pigment. The ability to use Mössbauer spectroscopy in forensic studies has been tested and the hypothesis of one and the same source of dissemination of the forged bank notes has been confirmed.
Since its discovery the Mössbauer effect has been a powerful probe of iron in magnetic materials and, together with neutron scattering and magnetic resonance, complements measurements of magnetic susceptibility and magnetization. The magnetic hyperfine splitting of the spectrum gives a measure of the magnetic moment on the iron atoms, and the line intensities enable the orientation of the magnetic moments to be determined. By applying external magnetic fields the local susceptibility of the iron atoms in paramagnets can be determined, and in magnetically ordered crystals magnetic phase changes may be induced and may be used to measure the magnetic anisotropy. In the early days this was used to determine the magnetic structure of crystalline ferromagnets, ferrimagnets and antiferromagnets. More modern applications include the study of amorphous and disordered crystalline materials (speromagnets, spin glasses, cluster glasses), incommensurate spin structures, fine particle magnets (superparamagnets and superferromagnets), magnetic multilayers, high flux density permanent magnet alloys (e.g. ) and high- superconductors.
True and forged USA dollar bank-notes, as well as true German marks, are the object of Mössbauer spectroscopy and X-ray fluorescence investigation. Initial results on the iron-containing pigments in printer ink are presented. The pigments show Mössbauer spectra typical for nonstoichiometric Fe3O4, γ-Fe2O3 and α-Fe or more complicated phases. Additional information about the elemental composition of pigments is obtained from X-ray fluorescence analyses. Some of the pigments are traced with rare earth elements. The relatively high concentration of iron-containing pigments in the printer ink used and the specificity of their Mössbauer spectra indicate that Mössbauer spectroscopy may be a useful tool in law courts for the identification of fakes and forgeries, and can also be used in industry for printer ink control.
Some subjects will be discussed that have recently received special attention or for which particularly interesting results
have been obtained. Significant progress has been made also in several other fields. Rather than to attempt to make a complete
overview, attention will be focused on a few selected topics only.
Comprehensive catalog of US paper money
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Mö ssbauer measurements on dollar and euro money pigments. In: Sixth Seeheim workshop on Mö ss-bauer spectroscopy, program and abstracts
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Rusanov V, Chakarova K, Winkler H, Trautwein AX, Mö ssbauer measurements on dollar and euro money pigments. In: Sixth Seeheim workshop on Mö ss-bauer spectroscopy, program and abstracts, Seeheim, Germany; June 07–11, 2006, p. 68.
US paper money guide and handbook
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Mö ssbauer measurements on dollar and euro money pigments
- V Rusanov
- K Chakarova
- H Winkler
- A X Trautwein
Rusanov V, Chakarova K, Winkler H, Trautwein AX, Mö ssbauer measurements
on dollar and euro money pigments. In: Sixth Seeheim workshop on Mö ssbauer spectroscopy, program and abstracts, Seeheim, Germany; June 07-11,
2006, p. 68.