Total Reflection X-ray Fluorescence System Research Articles

Using a portable total reflection X‐ray fluorescence system for a multielement analysis of Swiss mice brains with experimental Alzheimer's disease induced by β‐amyloid oligomers

Alzheimer's disease (AD) is a progressive and irreversible disorder whose pathological features include β‐amyloid (Aβ) plaques and neuronal and synaptic loss. Metals such as iron, copper, and zinc are increased in the brains of patients with AD. Those metals can interact with Aβ, resulting in the promotion of Aβ deposition and formation of plaque. However, no study analyzing the effects of single injection of Aβ soluble oligomers (AβOs) in the elements' homeostasis in mice was developed. Total reflection X‐ray fluorescence (TXRF) is a multielement analytical technique that can be utilized to identify and quantify trace elements present in a sample at very low concentrations. In this study, in order to evaluate the concentration of metals in brain regions of Swiss mice, three groups of female mice and three of male mice were studied: control, AD10, and AD100. The AD groups received an AβOs intracerebroventricular injection so as to induce experimental AD. Afterwards, a craniotomy was performed, and six brain compartments were dissected and evaluated. TXRF measurements were performed using a portable TXRF system that uses an X‐ray tube with a molybdenum anode and a detector Si‐PIN. It is proved to determine the following elements' concentrations: phosphorus, sulfur, potassium, iron, copper, zinc, and rubidium. Results showed differences in the elemental concentration in some brain regions between AD groups. These alterations suggest that AβOs act quickly, even before the amyloid plaques' formation, explaining cognitive deficits independently of amyloid plaques. This study helped to understand that this modification on elemental concentration can be influenced by AβOs.

Analysis of milk trace elements with a home-made portable automated total reflection x-ray fluorescence system

This paper presents a portable, high-tech, low-cost, total reflection X-ray fluorescence system. This system features a compact arrangement consisting of a 50 W X-ray mini-tube with a Mo anode and a Si-PIN detector, quartz reflectors, lucite monochromator and micrometric tables driven by step motors controlled through the Arduino programming software. A certified sample of bovine liver SRM 1577b by NIST was used for the validation of the portable automated TXRF system. The TXRF system was used in the analysis of bovine milk samples collected in the industrialized region of the city of Bauru, São Paulo. In the analysis of the bovine milk samples the following elements were detected: P, S, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Se, Rb and Sr. The TXRF portable automated system proved to be efficient, showing that it is possible to produce X-ray fluorescence with a low-cost system using a low-power X-ray tube and a compact Si-PIN detector.

Total reflection X-ray fluorescence medical applications: Elemental analysis of human urine

The main goal of this research is to define reference values of elemental concentration in human urine. The second topic is to develop a fast analytical method for multielemental analysis of human urine by means of a low-power benchtop total reflection X-ray fluorescence system. For this purpose a set of certified human urine and real samples was employed. All of the parameters affecting sample preparation and measurement conditions were carefully evaluated, and finally, the procedure for optimal urine preparation and optimal measurement conditions is defined. The accuracy and precision of the measurements were verified using an internal standardization approach for quantification. As results, the reference values of concentration of several elements (K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb and Sr) were defined on the basis of the analysis of 100 urine samples. Donors were presumably healthy volunteers from the Świętokrzyskie Province in Poland: 62 women and 38 men. Because of the strong asymmetry of elemental concentration distributions, the median and the 1st and 3rd quartiles reflect features of the distributions better than the mean value and standard deviation (which are proper for symmetric distributions). Finally, the 1st and 3rd quartiles were accepted as the initial and final values of the concentration reference range. For measurements, in which the concentration is below the detection limit of the method used (i.e. for Cr, Mn, Cu, Se), the well-known random-left censoring approach was applied for the statistical analysis of the results.

In Vivo Hypoglycemic Effect of Kigelia africana (Lam): Studies With Alloxan-Induced Diabetic Mice.

The claims by the traditional herbal medicine practitioners that Kigelia africana has bioactivity against several diseases, including diabetes mellitus, were investigated in this study. Type I diabetes mellitus was induced in mice by intraperitoneal administration of alloxan monohydrate followed by treatment with the therapeutic doses of the aqueous and ethyl acetate leaf extract of K africana to the experimentally diabetic mice. The treatment effects were compared with the normal control, diabetic control, and diabetic control rats treated with a standard antidiabetic drugs (insulin administered intraperitoneally at 1 IU/kg body weight in 0.1 mL physiological saline or glibenclamide administered orally at 3 mg/kg body weight in 0.1 mL physiological saline). Phytochemical composition of the leaf extract was assessed using standard procedures and mineral elements assessed using atomic absorption spectrophotometry and total reflection X-ray fluorescence system. Oral and intraperitoneal administration of the aqueous and ethyl acetate leaf extract caused a statistically significant dose-independent reduction in plasma glucose level in alloxan-induced diabetic mice. The observed hypoglycemic activity of this plant extract could be attributed to the observed phytochemicals and trace elements, which have been associated with exhibiting antidiabetic properties. Therefore, the data appear to support the hypoglycemic effects of K africana validating its folkloric usage.

In Vivo Antianaemic Effect and Safety of Aqueous Extracts of Erythrina abyssinica and Zanthoxylum usambarensis in Mice Models

This study was carried out to determine the hematinic effects and long term safety of Zanthoxylum usambarensis and Erythrina abyssinica in mice. Aqueous stem extracts of Z. usambarensis and E. abyssinica were screened for their haematinic activity in Phenylhydrazine induced anemic mice using the oral route. Hematological parameters were analysed as indices of anemia. The safety of these plant extracts was studied by orally administering 1 g/kg body weight of aqueous extracts daily in mice for thirty days and determining changes in body and organ weight, hematological and biochemical parameters. The mineral content of the extracts was estimated using Total Reflection X-Ray Fluorescence system (TRXF) while phytochemicals were assessed using standard procedures. Phenylhydrazine (PHZ) treatment induced macrocytic anemia. Administration of Z. usambarensis and E. abyssinica extracts at 100 mg/kg body weight daily for three weeks increased the red blood cell count, hemoglobin, and packed cell volume and decreased the mean cell volume and mean cell hemoglobin though E. abyssinica returned these parameters to normal. Administration of Z. usambarensis and E. abyssinica extracts at 1 g/kg body weight daily for four weeks significantly increased the activities of alkaline phosphatase, gamma glutamyltransferase, lactate dehydrogenase and amylase and the levels of urea and creatine in the treated mice. Extracts from both plants had alkaloids and flavonoids and minerals potassium, calcium, chromium, iron, copper, zinc, manganese, nickel, arsenic, and lead. This study has confirmed in vivo haematinic activity and safety of aqueous stem bark extracts of Z. usambarensis and E. abyssinica. The observed haematinic activity could be attributed to the phytonutrients present in these plants. The study recommends continued use of Z. usambarensis and E. abyssinica in the management of anaemia at the right doses as high doses are toxicity.

Blood Glucose Lowering Effect and Safety of the Aqueous Leaf Extracts of Zanha africana

Zanha africana has been used traditionally to manage many diseases including diabetes, however, its antidiabetic activity and safety is not well evaluated. The aim of this study was to determine in vivo hypoglycemic activity and safety of the aqueous leaf extracts of this plant in male Swiss white albino mice. The antidiabetic activity was screened in alloxan induced diabetic mice using oral and intraperitoneal routes. The safety of the extract was studied in mice that were orally and intraperitoneally administered with 1 g/kg body weight daily for 28 days by recording changes in body and organ weights, hematological and biochemical parameters. Mineral composition was estimated using total reflection X-ray fluorescence system and atomic absorption spectrometry. Phytochemical composition was assessed using standard procedures. The extract showed hypoglycemic activity at dose levels of 50, 100, 200, 300 mg/kg body weight. Administration of 1 g/kg body weight of the extract decreased the body weight gain using both routes. Intraperitoneal administration of the same dose increased the organ to body weight percentages of liver, brain and kidney, and elevated white blood cell count, lymphocyte count, and levels of γ-glutamyl transpeptidase, total bilirubin and direct bilirubin and deceased levels of aspartate aminotransferase and creatinine. Increase in levels of mean corpuscular hemoglobin, γ-glutamyl transpeptidase, lactate dehydrogenase and creatine kinase, and decrease in levels of platelets, alanine transaminase, aspartate aminotransferase, urea, creatinine, total bilirubin and direct bilirubin was recorded in mice orally administered with 1 g/kg body weight of the extract. The extract contained tannins, phenols, flavonoids, saponins, and alkaloids. Sodium, Chlorine, Potassium, Calcium, Titanium, Vanadium, Chromium, Manganese, Iron, Copper, Zinc, Arsenic, Cadmium, Magnesium, Nickel and Lead were present in the extracts at levels below the recommended daily allowance. The observed hypoglycemic activity and slight toxicity could be associated with the phytochemicals and mineral/ trace elements present in this extract.

In Vivo Antidiabetic Activity and Safety In Rats of Cissampelos pareira Traditionally Used In The Management of Diabetes Mellitus In Embu County, Kenya

Cissampelos pareira Linn has been used traditionally in the management of several diseases including diabetes mellitus but its efficacy and safety after long term use is not scientifically evaluated. The aim of this study was to determine in vivo hypoglycemic activity and safety of aqueous leaf extracts of C. pareira in white male albino rats. The extracts were screened for their hypoglycemic activity in alloxan induced diabetic rats using the oral and intraperitoneal routes. The safety of these extracts was studied in rats orally or intraperitoneally administered with 1 g/kg body weight daily for 28 days by recording the changes in body and organ weight, hematological and biochemical parameters and histology. Mineral composition of the extracts were estimated using total reflection X-ray fluorescence system (TRXF) while the types and quantities of phytochemicals present were assessed using standard procedures. Aqueous extracts orally and intraperitoneally administered at 50 mg/kg, 100 mg/kg and 150 mg/kg body weight demonstrated hypoglycemic activity with the intraperitoneal route being more effective than the oral route. Oral and intraperitoneal dose of 1 g/kg body weight of the leaf extracts significantly reduced the body weight gain. The same intraperitoneal dose increased the liver and spleen, and decreased the testis weight; and reduced the hemoglobin levels, packed cell volume and increased the platelet count; increased the activity of aspartate aminotransferase, and lactate dehydrogenase, and decreased the activity of alkaline phosphatase, γ-glutamyltransferase, and creatine kinase and histologically slightly injured the liver and spleen and orally increased the activity of alanine aminotransferase, lactate dehydrogenase, and creatine kinase, and decreased the activity of aspartate aminotransferase and γ-glutamyltransferase. The extracts contained phenols, tannins, flavonoids, alkaloids, terpenoids, sterols, and reducing sugars. Potassium, calcium, and iron levels in the extracts were below the recommended daily allowance. In conclusion, the observed hypoglycemic activity and slight toxicity could be associated with the phytonutrients present in this plant extract. This study recommends continued use of this plant as an herbal medicine.

In-Vivo Antidiabetic Activity and Safety of The Aqueous Stem Bark Extract of Kleinia squarrosa

Kleinia squarrosa has been used traditionally to manage several diseases including diabetes, however, its efficacy and safety is not well evaluated. The aim of this study was to determine in-vivo hypoglycemic activity and safety of the aqueous stem bark extracts of this plant in male swiss white albino mice. The antidiabetic activity was screened in alloxan induced diabetic mice using oral and intraperitoneal routes. The safety of the extract was studied in mice that were orally and intraperitoneally administered with 1 g/kg body weight daily for 28 days by recording changes in body and organ weights, hematological and biochemical parameters and histology. Mineral composition was estimated using total reflection X-ray fluorescence system (TRXF) and atomic absorption spectrometry (AAS). Phytochemical composition was assessed using standard procedures. The extract showed hypoglycemic activity at dose levels of 50, 100, 200, 300 mg/kg body weight. Administration of 1 g/kg body weight of the extract decreased the body weight gain using both routes, and altered the organ to body weight percentage of the liver and lungs for intraperitoneal route while oral route only altered the liver. Oral administration of the same dose caused a change in levels of RBC, ALP, AST, LDH CK and Creatinine while the same intraperitoneal dose caused a change in RBC, WBC, Hb, PCV, PLT, MCH, MCHC, neutrophils, lymphocytes, eosinophils, monocytes and biochemical parameters: AST, ALT, GGT, LDH, T-BIL, D-BIL, Urea and Creatinine. Moreover, intraperitoneal administration caused significant histological lesions to the kidney, liver and spleen. The extracts contained tannins, phenols, flavonoids, saponins, and alkaloids. Sodium, Chlorine, Potassium, Calcium, Titanium, Vanadium, Chromium, Manganese, Iron, Copper, Zinc, Arsenic, Cadmium, Magnesium, Nickel and Lead were present in the extracts at levels below the recommended daily allowance. The observed hypoglycemic activity and slight toxicity could be associated with the phytochemicals present in this plant extract.

In-Vivo Anti-hyperglycemic Activity and Safety of The Aqueous Stem Bark Extracts of Aloe secundiflora

Aloe secundiflora has been used traditionally to manage many diseases including diabetes, however, its antidiabetic activity and safety is not well evaluated. The aim of this study was to determine in vivo hypoglycemic activity and safety of the aqueous stem bark extracts of this plant in male swiss white albino mice. The antidiabetic activity was screened in alloxan induced diabetic mice using oral and intraperitoneal routes. The safety of the extract was studied in mice that were orally and intraperitoneally administered with 1 g/kg body weight of the extract daily for 28 days by recording changes in body and organ weights, hematological and biochemical parameters. Mineral composition was estimated using total reflection X-ray fluorescence system and atomic absorption spectrometry. Phytochemical composition was assessed using standard procedures. The extract showed significant and consistent hypoglycemic activity at dose levels of 50 mg/kg body weight through oral route and 300 mg/kg body weight through intraperitoneal route. Oral administration of 1 g/kg body weight of the extract decreased levels of platelets, alanine transaminase, aspartate aminotransferase, alkaline phosphatase, creatinine and direct bilirubin while elevated the level of creatine kinase. Reduction in the growth rate and increase in percent of organ to body weight of brain together with elevated levels of mean corpuscular hemoglobin concentration, γ-glutamyl transpeptidase, α-amylase, alkaline phosphatase, total bilirubin and direct bilirubin were recorded in mice intraperitoneally administered with 1 g/kg body weight of the extract. The extracts contained tannins, phenols, flavonoids, saponins, and alkaloids. Sodium, Chlorine, Potassium, Calcium, Titanium, Vanadium, Chromium, Manganese, Iron, Copper, Zinc, Arsenic, Cadmium, and Magnesium were present in the extracts at levels below the recommended daily allowance. The observed hypoglycemic activity and slight toxicity could be associated with the phytochemicals and mineral/trace elements present in this extract.

The Hypoglycemic Activity and Safety of Aqueous Stem Bark Extracts of Acacia nilotica

Acacia nilotica is used traditionally to manage several diseases including Diabetes mellitus, however, its efficacy and safety is not well evaluated. The aim of this study was to determine in vivo the hypoglycemic activity and safety of the aqueous stem bark extracts of this plant in male swiss white albino mice. The anti-diabetic activity was screened in alloxan induced diabetic mice using oral and intra-peritoneal routes. The safety of this plant extract was studied in mice that were orally and intraperitoneally administered with 1 g/kg body weight daily for 28 days by recording changes in body and organ weight, hematological and biochemical parameters and histology. Mineral composition was estimated using total reflection X-ray fluorescence system and atomic absorption spectrometry. Phytochemical composition was assessed using standard procedures. The extract administered at 50, 100, 200, 300 mg/kg body weight showed hypoglycemic activity. The Intraperitoneal route was more effective compared to the oral route. Intraperitoneal administration of the extract at 1 g/kg body weight significantly reduced body weight gain, percent organ to body weight of testes, while oral administration at the same dose decreased levels of platelets. Oral administration of the aqueous stem bark extracts of A. nilotica at 1 g/kg body weight caused increase in levels of γ-glutamyl transpeptidase, Creatine kinase, and Total bilirubin while decreasing levels of alanine transaminase, aspartate aminotransferase, α-Amylase, and Alkaline phosphatase. Intraperitoneal administration of the same dose decreased levels of aspartate aminotransferase. The aqueous stem bark extract of A. nilotica contained tannins, total phenols, flavonoids, saponins, and alkaloids. Sodium, chloride, potassium, calcium, titanium, vanadium, chromium, manganese, iron, copper, zinc, arsenic, nickel, lead, and cadmium were present in the aqueous stem bark extracts of A. nilotica at levels below the recommended daily allowance. In conclusion, the observed hypoglycemic activity and slight toxicity could be associated with the phytochemicals present in this plant extract.

Development and characterization of a portable total reflection X-ray fluorescence system using a waveguide for trace elements analysis.

This paper presents a portable total reflection X-ray fluorescence system composed of a 15 W X-ray tube, with a gold anode, a waveguide constituted by two Perspex(®) parallel plates, a Si PIN detector and a quartz optical flat. The critical angle of the total reflection system was experimentally determined by measuring a zinc solution (100 mg/L). The accuracy of the system was checked using SRM 1577b Bovine Liver by NIST as standard reference material. We obtained the absolute detection limits of the following elements: P (450 ± 40 ng), S (200 ± 31 ng), K (30 ± 2.5 ng), Ca (19 ± 3.5 ng), Mn (4.1 ± 0.5 ng), Fe (3.6 ± 0.9 ng), Cu (3.3 ± 0.4 ng) and Zn (3.5 ± 0.3 ng). This paper shows that it is possible to produce total reflection X-ray fluorescence with very compact, efficient, low-cost and easy-to-handle instrumentation using a low-power X-ray tube and a Si PIN compact detector.

Antidiabetic and Safety of Lantana rhodesiensis in Alloxan Induced Diabetic Rats

Lantana rhodesiensis Linn is used traditionally in the management of several diseases including diabetes mellitus; however, its efficacy and safety is not scientifically evaluated. The aim of this study was to determine in vivo hypoglycemic activity and safety of aqueous extracts of L. rhodesiensis in white male albino rats. Aqueous extracts were screened for their hypoglycemic activity in alloxan induced diabetic rats using the oral and intraperitoneal routes. The safety of these extracts was studied in rats orally or intraperitoneally administered with 1 g/kg body weight daily for 28 days by recording the changes in body and organ weight, hematological and biochemical parameters and histology. Mineral compositions of the extracts were estimated using total reflection X-Ray Fluorescence System (TRXF) while the types of phytochemicals present were assessed using standard procedures. Aqueous extracts orally and intraperitoneally administered at 50, 100 and 150 mg/kg body weight demonstrated hypoglycemic activity with the intraperitoneal route being more effective than the oral route. Oral and intraperitoneal dose of 1 g/kg body weight of the extracts significantly reduced the body weight gain, increased the testis and spleen, and decreased the lung weight; reduced the hemoglobin levels, red blood cell count, packed cell volume and increased the neutrophil count; decreased the activity of γ-glutamyltransferase and histologically mildly reduced lymphoid follicles. Orally, the same dose decreased the red blood cell count, packed cell volume, mean cell volume, monocyte and platelet count; increased the activity of lactate dehydrogenase, and creatine kinase. The extract contained phenols, tannins, flavonoids, alkaloids, sterols, terpenoids, cardiac glycosides, phylobatannins, resins, and bound anthrax quinones. Potassium, calcium, manganese, iron, lead and zinc levels in the extracts were below the recommended daily allowance. In conclusion, the observed hypoglycemic activity and slight toxicity could be associated with the phytonutrients present in this plant. This study recommends use of this plant as herbal medicine.

Nitrogen purged TXRF for the quantification of silver and palladium

Total reflection X-ray fluorescence (TXRF) analysis is a powerful technique for simultaneous multi-element analysis. Benefits include limits of detection in the microgram per litre range, limited sample preparation for liquid samples and low operating costs. However, the determination of elements such as silver and palladium suffers from interferences, e.g. if an X-ray tube with a molybdenum anode is used, which normally offers the lowest detection limits for most of the elements of the periodic table. Argon emits its X-ray fluorescence radiation in the same energy range as these metals and therefore hinders their detection and subsequent quantification. Since argon is abundant in the atmosphere with approx. 0.93% and is easily activated by X-rays in a TXRF instrument, this interference is always present under routine measurement conditions. We have developed a new method for the analysis of silver and palladium by TXRF. A commercially available TXRF system was modified for being operated under a nitrogen purged atmosphere by surrounding it with an airtight and water-cooled box, which still allows accessing the main hardware components, changing the sample discs or performing long term measurements without temperature drift effects. An easy removal of the box is possible for a rapid change between the nitrogen purged and the common mode under ambient atmosphere. After flushing the system with nitrogen, the signal of argon decreased significantly, allowing the determination of silver and palladium with limits of detection for silver and palladium of 6.6 μg L−1 and 16.6 μg L−1 respectively.

Modelling of a total reflection X-ray fluorescence (TXRF) system

A robust computer program to simulate X-ray fluorescence (XRF) system and particularly applied to the total reflection mode is presented in this paper. The simulation of the different stages involved in x-ray fluorescence emissions was carried out by writing a suite of computer programs using FORTRAN programming language. These computer simulated XRF stages were then integrated together to generate a general robust model which was run with the digital visual Fortran 6.0 compiler set-up. The model was validated by comparison with experimental spectrum from the TXRF system in the Physics Department of the Obafemi Awolowo University, Ile-Ife. Trail experiments were carried out with this model to determine optimum conditions for detecting certain elements of interest under various analytical conditions in given samples. Results of these trail experiments show that the detectability of elements improved with increasing applied voltages and atomic number of elements. Variation of geometry such as the glancing incidence angle of the excitation and the nature of the support itself were also observed to effect the detect ability of the elements. Nigerian Journal of Physics Vol. 16(2) 2004: 97-104

Adaptation of a commercial total reflection X-ray fluorescence system for wafer surface analysis equipped with a new generation of silicon drift detector

Within the framework of a collaborative project, it is shown that commercial total reflection X-ray fluorescence (TXRF) systems used in laboratories can easily be upgraded with a silicon drift detector (SDD). SDDs have advantages when used with fully automatized wafer analyzers working under cleanroom conditions, because no liquid nitrogen is required as they are electrically cooled. The goal of this work was the integration of a KETEK 10 mm 2 SDD in an ATOMIKA 8030W wafer analyzer with special attention to maintain the high degree of automation of the system. An electronic device was designed to establish communication between the SDD and the TXRF electronic control system. The adapted system was tested and compared with the original setup using an 80 mm 2 Si(Li) detector. Multielement droplet samples on silicon wafers were analyzed and the results showed two times better detection limits for the Si(Li) detector for 1000 pg Ni in comparison to the SDD. Additionally, a RADIANT 50 mm 2 SDD (VORTEX) was tested which showed identical detection limits compared to the 80 mm 2 Si(Li) detector.

Focused beam total reflection X-ray fluorescence with low power sources coupled to doubly curved crystal optics

A focused beam total X-ray fluorescence technique was developed based on doubly curved crystal optics. This technique provides good detection sensitivity and spatial resolution for localized detection of surface deposits. Compact low power X-ray sources were used to demonstrate the benefit of the X-ray optics for focusing Cr Kα, Cu Kα and Mo Kα radiation. The detection capability of the focused beam Total reflection X-ray fluorescence system was investigated with dried droplets of calibrated low concentration solutions. Detection limits at the femtogram level were demonstrated.

Development of a total reflection X-ray fluorescence spectrometer for ultra-trace element analysis

A simple and fairly inexpensive total reflection X-ray fluorescence (TXRF) spectrometer has been designed, constructed and realized. The spectrometer is capable of ultra-trace multielement analysis as well as performs surface characterization of thin films. The TXRF setup comprises of an X-ray generator, a slit-collimator arrangement, a monochromator/cutoff-stage, a sample reflector stage and an X-ray detection system. The glancing angle of incidence on the two reflectors is implemented using a sine-bar mechanism that enables precise angle adjustments. An energy dispersive detector and a GM counter are employed for measuring respectively the fluorescence intensities and the direct X-ray beam intensity. A Cu-target X-ray generator with its line focus window is used as an excitation source. The spectrometer is quite portable with its compact design and use of a peltier cooled solid state detector for energy dispersive detection. Alignment and characterization of the TXRF system has been performed and the minimum detection limits for various elements have been determined to be in the range of 100 pg to 5 ng even at low X-ray generator powers of 30 kV, 5 mA. The capability of the TXRF system developed for thin film characterization is also demonstrated.

Trace analysis for 300 mm wafers and processes with total reflection X-ray fluorescence

Total reflection X-ray fluorescence (TXRF) is essential for 300-mm silicon wafer production and fabrication of semiconductor devices. The 300-mm TXRF enables non-destructive contamination analysis on wafers for process development and process control. The TXRF system shows a very stable continuous operation, which allows accurate trace and ultra trace analysis on the silicon surface. It is equipped with two excitation sources covering the requirements of very sensitive measurement and wide element range. The TXRF is a key technology for contamination control during wafer reclaim. For this purpose we show that the system is able to examine the wafers during different processing states of reclaim. The system sensitivity is influenced by the surface of the wafer. For important processing steps, e.g. double side polishing, the sensitivity is as good as for measurements on hazefree polished wafers. We show with TXRF that cross-contamination with copper during double side polishing is suppressed.

Limits of detection of a total reflection X-ray fluorescence system with double reflection module.

An X-ray tube with a Mo target and Zr filter, operated at 45 kV/20 mA, was used to excite samples (5 microL deposited on a quartz support) and the total reflection angle condition was obtained with a double reflector module built with two 10-cm-long 7-mm-thick quartz crystals placed 50 microns apart. A high-resolution spectrometer based on a Si(Li) detector coupled to a multichannel analyzer was used for X-ray detection and the spectra were interpreted with the AXIL software. The system was calibrated with standard chemical solutions containing Cr, Fe, Cu, Zn, and Pb, and Y was used as an internal standard to correct eventual geometric errors and high-voltage instabilities of the X-ray generator. The limits of detection were 19, 9, 5, and 4 ng/mL for Cr, Fe, Cu, and Zn, respectively, analyzed through characteristic K alpha X-rays, and 7 ng/mL for Pb, through L alpha X-rays, considering 50 microL samples deposited and dried on a quartz support, to be excited/detected for 1000 s.

Precision measurements with the total reflection x-ray fluorescence system in Dar es Salaam

Precision measurements with the total reflection x-ray fluorescence system in Dar es Salaam