Spectroscopic Performance Research Articles

Strong and broadband 2.7 μm fluorescence of Yb3+/Er3+ co-doped ZnO modified tungsten tellurite glasses for broadband mid-infrared optical amplifiers and tunable fiber lasers

Strong and broadband 2.7 μm fluorescence with effective emission linewidth of 140.4 nm has been achieved in 1 mol% Yb2O3 and 1 mol% Er2O3 co-doped ZnO modified tungsten tellurite glass under an excitation from a 980 nm laser diode. The influences of Yb3+ concentration on 2.7 μm spectroscopic properties of Yb3+/Er3+ co-doped ZnO modified tungsten tellurite glasses were analyzed by absorption spectra, emission spectra and lifetime measurement. Long lifetime of 4I11/2 level (649.4 μs), high spontaneous radiative transition probability (65.1 s−1), large emission cross section (8.27 × 10−21 cm2) and figure of merit (5.37 × 10−24 cm2s) near 2.7 μm ensure intense 2.7 μm emission. Furthermore, the energy transfer coefficients between Yb3+ and Er3+ ions are quantitatively determined to explain the reinforcement of 2.7 μm fluorescence. Therefore, Yb3+/Er3+ co-doped ZnO modified tungsten tellurite glasses with better 2.7 μm spectroscopic performances are predominant candidates in constructing broadband mid-infrared optical amplifiers and tunable fiber lasers.

Spectroscopic Performance of Otoscopes during Otoscopic Examination by LED Headlight

Spectroscopic Performance of Otoscopes during Otoscopic Examination by LED Headlight

Co-relational study on embelin content in wild and cultivated non fruit plant parts of Embelia tsjeriam-cottam A. DC.

Embelin, one of significant bio-active benzoquinone compound, acts as active principle in fruits of Embelia species and has significant role as a potent source for several formulations. Aim of current research study was to estimate the variation in embelin content different non fruit parts of Embelia tsjeriam-cottam (leaf, stem bark and roots) from both wild and cultivated sources. This was achieved by using spectroscopic method and high performance liquid chromatography (HPLC) analysis method, after purification through column chromatography (CC) and preparative thin layer chromatography technique (PTLC). In case of spectrophotometric analysis, wild Embelia tsjeriam-cottam plants showed embelin content in between 1.14-1.96% dry wt. and the cultivated plants 0.92-1.70% dry wt. Similarly in case of HPLC analysis, wild E. tsjeriam-cottam plants possessed embelin content in a range of 0.033-0.098% dry wt. and cultivated plants yielded embelin in between 0.021-0.071% dry wt. In both cases, amongst all the selected non fruit plant parts, the chloroform extracted root samples possessed highest and the methanol extracted leaf samples yielded lowest embelin content. When comparison was done between the wild and cultivated plant parts in terms of embelin content, wild plants were ascertained to be highly potent than the cultivated plants and root samples possessed highest embelin content followed by stem bark and leaf parts.

Smart Diffraction Gratings Based on the Shape Memory Effect.

The shape memory effect is the capability of a structure or a material that can be deformed into a certain temporary shape under external stimulus, and the shape will be fixed without the stimulus. The recovery process can be triggered by the same stimulus. The intelligent tunable device based on the shape memory effect has a wide range of applications in many fields. In the optical field, smart diffraction gratings can accomplish in situ optical diffractions according to requirements, meeting the high demand in the next generation of smart optical systems. However, it is essential to construct high-precision grating structures based on shape memory materials. Here, a smart diffraction grating based on UV-curable shape memory polymers (SMPs) via two-beam interference is reported, with nano-scale precision, excellent deformability and recovery ability, and adjustable spectroscopic performance. More importantly, based on the shape memory effect, grating structures that surpass the precision of the fabrication system can be obtained. The smart grating exhibits rapid deformation and recovery upon heating and long-term storage capability, which facilitates them to be applied in optics, electronics, and integrated sensing.

Potentialities of High-Resolution 3-D CZT Drift Strip Detectors for Prompt Gamma-Ray Measurements in BNCT.

Recently, new high-resolution cadmium–zinc–telluride (CZT) drift strip detectors for room temperature gamma-ray spectroscopic imaging were developed by our group. The CZT detectors equipped with orthogonal anode/cathode collecting strips, drift strips and dedicated pulse processing allow a detection area of 6 × 20 mm2 and excellent room temperature spectroscopic performance (0.82% FWHM at 661.7 keV). In this work, we investigated the potentialities of these detectors for prompt gamma-ray spectroscopy (PGS) in boron neutron capture therapy (BNCT). The detectors, exploiting the measurement of the 478 keV prompt gamma rays emitted by 94% 7Li nuclides from the 10B(n, α)7Li reaction, are very appealing for the development of single-photon emission computed tomography (SPECT) systems and Compton cameras in BNCT. High-resolution gamma-ray spectra from 10B samples under thermal neutrons were measured at the T.R.I.G.A. Mark II research nuclear reactor of the University of Pavia (Italy).

HEXITEC 2 × 2 tiled hard X-ray spectroscopic imaging detector system

HEXITEC is a spectroscopic imaging X-ray detector technology developed at the STFC Rutherford Appleton Laboratory for X-ray and γ-ray spectroscopic imaging applications. Each module has 80 × 80 pixels on a 250 μm pixel pitch, and has been implemented successfully in a number of applications. This paper presents the HEXITEC 2 × 2 detector system, a tiled array of 4 HEXITEC modules read out simultaneously, which provides an active area of 16 cm2. Systems have been produced using 1 mm thick Cadmium Telluride (CdTe) and 2 mm thick Cadmium Zinc Telluride (CdZnTe) sensor material. In this paper the system and data processing methods are presented, and the performance of the systems are evaluated. The detectors were energy calibrated using an 241Am sealed source. Three types of charge sharing correction were applied to the data-charge sharing addition (CSA), charge sharing discrimination (CSD), and energy curve correction (ECC) which compensates for energy lost in the inter-pixel region. ECC recovers an additional 34 % of counts in the 59.5 keV peak in CdTe compared to the use of CSD; an important improvement for photon-starved applications. Due to the high frame rate of the camera system (6.3 kHz) an additional End of Frame (EOF) correction was also applied to 6.0 % of events to correct for signals that were readout whilst the signal was still forming. After correction, both detector materials were found to have excellent spectroscopic performance with a mean energy resolution (FWHM) of 1.17 keV and 1.16 keV for CdZnTe and CdTe respectively. These results successfully demonstrate the ability to construct tiled arrays of HEXITEC modules to provide larger imaging areas.

Influence of the concentration of chenodeoxycholic acid on the performance of the N719 dye

The influence of the Chenodeoxycholic acid (CDCA) at different concentrations on the spectroscopic and photovoltaic performances of the N719 dye was determined. Absorption analyses revealed the excellent capacity of the CDCA in stabilizing the N719 dye. The N719 dye exhibited hydroxyl and carboxylic functional groups that were accountable for the strong interactions and fast transport of electrons to the TiO2 surface. The photoluminescence emission spectroscopy of the CDCA-incorporated dye exhibited the feasibility of a large photocurrent generation. The interaction mechanism of CDCA within the N719 dye influenced the efficiency of the fabricated cell because the high photoconversion efficiency of 4.07% was recorded for 0 mM CDCA. This finding was because CDCA decreased the electrolyte contact with the N719 dye, resulting in charge accumulation in the electrolyte and decreased electron density in the N719 dye. Present findings are beneficial for the development of efficient dye-based DSSCs.

Towards the TRISTAN detector: Characterization of a 47-pixel monolithic SDD array

Multi-pixel Silicon Drift Detectors (SDD), widely employed in X-ray applications, can also be applied to electron spectroscopy experiments. The objective of the TRISTAN project is to equip the KATRIN beam line with a multi-pixel SDD focal plane array. This would allow to extend the physics program of KATRIN, whose main goal is the determination of the neutrino mass via a precise measurement of the tritium beta decay spectrum close to the endpoint. An extension of the measurement interval would enable a sensitive search for physics beyond the standard model, in particular keV-scale sterile neutrinos, a prime dark matter candidate. The SDD technology guarantees excellent energy resolution and high throughput capabilities. A custom 47-pixel prototype, based on a monolithic SDD tile, has been developed and tested for the TRISTAN project. The full functionality of the system has been verified for all 47 channels. Good spectroscopic performance has been observed with a 55Fe X-ray source. This is a crucial step towards the realization of the final 21-fold 166-pixel TRISTAN focal plane detector.

Characterisation of the HEXITEC[formula omitted] X-ray spectroscopic imaging detector incorporating through-silicon via (TSV) technology

In this paper a new version of the HEXITEC spectroscopic imaging technology is presented. The HEXITEC4S ASIC maintains the same pixel electronics but, unlike the previous design, contains no I/O pads on the top surface of the ASIC. The I/O pads, used for control and readout, are now produced on the bottom metal layer of the ASIC and are accessed using a deep through-silicon via process (TSV) developed by TMicro (Japan). Wire bonding then takes place on a redistribution layer produced on the rear surface of the ASIC. The use of this TSV processing means that devices are four-side-buttable and can be used to produce detectors from multiple modules with minimal dead area. TSV processing was completed on two wafers of HEXITEC4S devices and probe testing demonstrated a working ASIC yield of 75% and 43% for the two wafers. In order to test the performance of detectors, a 100 mm diameter wafer of spectroscopic grade GaAs:Cr was fabricated by Tomsk State University (Russia). The wafer consisted of HEXITEC4S and standard HEXITEC devices which allows the performance of the TSV detectors to be compared to those of the standard system using sensor material with near-identical properties. A comparison of the spectroscopic performance of these devices demonstrated a relatively minor difference between the HEXITEC4S and HEXITEC devices with FWHM@60keV measured to be 4.1 keV and 4.5 keV respectively. These results demonstrate that this deep TSV processing for the redistribution of the detector I/O can be successfully used to produce flat panels of HEXITEC detectors with minimal dead area between modules.

Ammonia-methane ratios from H-band near-infrared spectra of late-T and Y dwarfs

Aims. Our goals are to investigate the relative absorption strengths of ammonia and methane using low-resolution H-band (1.5−1.7 microns) spectra obtained in the laboratory and compared with observational spectra of late-T and Y dwarfs, and to estimate what can be expected from the wide-angle low-resolution near-infrared spectroscopic survey that will be provided by the upcoming Euclid space mission. Methods. Gas cells containing ammonia and methane at atmospheric pressure were custom-made in our chemical laboratory. Low-resolution near-infrared spectroscopy of these gas cells was collected in our optical laboratory. It is compared with simulated spectra using the high-resolution transmission molecular absorption database (HITRAN) for temperatures of 300 K and 500 K, and with near-infrared spectra of late-T dwarfs, Y dwarfs, Jupiter, and Saturn. We selected for this investigation the spectral region between 1.5 and 1.7 microns (H band) because it is covered by the Euclid red grism, it is particularly sensitive to the relative proportions of ammonia and methane opacity, and it is free from strong contributions of other abundant molecules, such as water vapor. Results. The laboratory spectra showed that the ammonia and methane features present in the simulations that used the HITRAN database are incomplete. Using our laboratory spectra, we propose a modified version of the NH3-H spectral ratio with expanded integration limits that increases the amplitude of variation in the index with respect to spectral type. Combinations of our laboratory spectra were used to find the best fits to the observed spectra with the relative absorption ratio of ammonia to methane as a free parameter. A relationship was found between the Teff and the ratio of ammonia to methane from spectral classes T5 to Y2 (1100 K–350 K), in fairly good qualitative agreement with theoretical predictions for high-gravity objects and temperatures from 1100 K to 500 K. The ammonia-to-methane ratios in late-T and Y dwarfs are similar to that of Jupiter, suggesting a similar chemical composition. Simulations of the spectroscopic performance of Euclid suggest that it will yield Teff values and ratios of ammonia to methane for over 103 late-T dwarfs in the entire wide survey.

Bias polarization characterization of Al/CdTe/Pt Schottky X-ray detector for industrial applications

Al/CdTe/Pt Schottky diodes are commonly used as X-ray and γ-ray detectors thanks to their high absorption coefficients and room temperature working conditions. One known drawback is the bias induced polarization, which downgrades the spectroscopic performances by progressively decreasing the charge collection efficiency. In the frame of charge accumulation model (CAM), the bias induced polarization is explained with Cd vacancies that create a deep acceptor level inside the gap: when a reverse voltage is applied, this level is thermally populated deforming the electric field inside the detector. We measured the reverse current transient at different temperatures and interpreted the experimental results with the CAM. In particular, we investigated the Schottky barrier height, its relation to the electric field at the anode, the ratio between deep trap concentration and de-trapping time and the energy of the deep acceptor level. We estimate an energy of 0.59eV above the valence band edge for the acceptor level. We propose a variation to the CAM that takes into account two deep acceptor levels, instead of only one, this allows to improve the fittings of the time dependence of the electric field at the anode.

Development of a gamma-ray imaging detector based on ceramic scintillators with SiPM readout

Depth of interaction (DOI) measurements can provide additional position information when long scintillator bars or scintillator pixels with relatively large thickness are employed in gamma-ray imaging detectors. In this study, commercially available GGAG ceramic scintillators were used to fabricate a gamma-ray imaging detector. The light attenuation, DOI resolution, and spectroscopic performance of 3.0× 3.0× 48.0 mm3 ceramic bars were evaluated using double-side SiPM readout. The measured full width at half maximum (FWHM) energy resolution values ranged between 7.6% and 8.7% at 511 keV. The DOI resolution was approximately 4 mm (FWHM). A prototype two-layer Compton imaging detector was fabricated based on 32 ceramic bars and the signals were readout using four 16-ch application-specific integrated circuits. The lutetium background was evaluated and a 22Na point source (0.19 μSv/h 511 keV gamma-ray dose rate at 50 cm) was used to verify the feasibility of using the commercial GGAG ceramic material in nuclear security applications. The source can be located within 120 s using a simple back projection method. The angular resolution measure was estimated as 15∘ (FWHM). A filtered back projection based algorithm improved the angular resolution (FWHM) to 9.2∘.

GAMMA: A 16-Channel Spectroscopic ASIC for SiPMs Readout With 84-dB Dynamic Range

Gain amplitude modulation multichannel ASIC (GAMMA) is a 16-channel application specified integrated circuit (ASIC), designed in 0.35- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> technology to read the charge provided by silicon photomultipliers (SiPMs) on a wide amplitude range. This chip was designed to satisfy the demanding requirements of the INFN the GAMMA project, where a 3” <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times3$ </tex-math></inline-formula> ” large lanthanum bromide crystal is to be read by SiPMs, aiming at state-of-the-art energy resolution. Because the energy range of the application is 100 keV–20 MeV, signals in a wide dynamic range (DR) have to be processed by the ASIC. This wide DR requirement raised the necessity of an adaptive gain change solution in order to guarantee a high signal-to-noise ratio together with a large full-scale range. While the ASIC input stage features a programmable static gain, the analog filtering channel exploits a self-triggered gated integrator stage with an automatically adjusted gain for each detected input current pulse; one of the following values is selected: 10, 2, or 0.83 [mV/pC]. The gated integrator gain is predictively adjusted before the circuit reaches saturation due to a time-gated threshold mechanism and provides negligible charge loss when the gain is switched (< 20 fC). A preintegration feature is also implemented in order to get rid of nonlinearity due to delays in the integration phase that could take place in a multi-ASIC system. The ASIC uses 5- and 3.3-V bias voltages, the overall power consumption being 280 mW. The ASIC was tested with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$12\times12$ </tex-math></inline-formula> SiPMs matrix coupled with a 3 inch LaBr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , providing good spectroscopic performances (2.6% at the <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs photopeak emission energy of 662 keV), and was also tested irradiating the SiPMs with fast, bright NUV light pulses, in order to explore the ASIC wide range coverage while simulating the scintillation light emission of a lanthanum bromide crystal.

Degradation Mechanisms of the Detector Properties of CdTe and CdZnTe Under the Influence of Gamma Irradiation

This work is devoted to the study of the mechanisms of the influence of radiation defects, arising under the influence of gamma irradiation, on the change in resistivity ρ, lifetime of nonequilibrium electrons τn and holes τp, in CdTe:Cl and Cd0.9Zn0.1Te as well as the collection efficiency η of uncooled radiation detectors based on these materials, by computer simulation method. Radiation defects, that are corresponded by deep energy levels in the band gap, act as trapping centers of nonequilibrium charge carriers, noticeably affect the degree of compensation by changing ρ of the detector material, the recombination processes by decreasing τn and τp, what ultimately can cause degradation of the charges collection efficiency η. The specific reasons for the deterioration of the detector properties of CdTe:Cl and Cd0.9Zn0.1Te under the influence of gamma irradiation were identified, and the main factors leading to complete degradation of the recording ability of detectors based on these semiconductors during their bombardment by 60Co gamma quanta were determined. The gradual degradation of the spectroscopic performance of CdTe:Cl-based detectors during gamma irradiation occurs due to the continuous formation of cadmium vacancies VCd and acceptor complexes VCd – Cl, which continuously shift Fermi level towards valence band and decrease ρ. The complete performance degradation of CdTe detectors takes place mainly due to the capture of nonequilibrium electrons at energy level of interstitial tellurium Te(I). The invariable spectroscopic properties of CdZnTe-based sensors under gamma irradiation up to 25 kGy occur due to the mechanism of radiative self-compensation by formation of substitutional defect TeZn. At the final stage of irradiation, a sharp deterioration in the detector properties of CdZnTe occurs, mainly due to the capture and recombination of nonequilibrium charge carriers at the level of the Te(I) defect. The different radiation resistances of CdZnTe and CdTe:Cl can be explained by different behavior of Fermi level EF in these semiconductors under gamma irradiation. EF in CdZnTe under radiation exposure remains near the middle of band gap, and in CdTe it drifts to the valence band. The rate of capture and recombination through Te(I) donor level in CdTe:Cl is lower than in CdZnTe due to the larger difference between the Fermi level and the radiation defect Te(I) level in cadmium telluride. Thereby, the complete degradation of the CdTe:Cl detector occurs at a higher concentration of radiation defect Te(I), and hence after a higher irradiation dose of 50 kGy compared with a dose of 30 kGy required for degradation of CdZnTe detector properties.

Insight into the impact of the substituent modification on the photovoltaic performance of ferrocenyl chalcones based DSSCs

The design, synthesis, spectroscopic, computational and solar cell performance studies of two new ferrocenyl chalcones (Fc-O1 and Fc-S2) were synthesized by the Claisen-Schmidt condensation reaction. In the synthesized molecules, the enone moiety acts as an efficient π-bridge that links the donor ferrocene derivative with methyl-furan (Fc-O1) and bithiophene (Fc-S2) substituents which permits good viability in fine-tuning the intramolecular charge transfer (ICT) and optical absorption spectrum. The chemical structure of the compounds have been elucidated by proton and carbon NMR as well as FTIR spectroscopies. The comparison study between the structures of these ferrocenyl chalcones were done by XRD and computational investigations. The substitution of bithiophene derivative on the Fc-S2 revealed the improvement of the structure planarity as compared to slightly twisted structure of Fc-O1. Fc-O1 and Fc-S2 exhibited large maximum absorption wavelength within the UV–Vis region (~485 ​nm), suggesting their potential as dye sensitizer in DSSC application. The compounds also possessed suitable energy levels of HOMO and LUMO for utilization as sensitizer in DSSC to ensure the process of electron injection and dye regeneration. A good ICT due to its planarity, large absorption maximum in visible range and low-lying HOMO energy level of Fc-S2 give rise to the higher conversion efficiency in DSSC study as in comparison to Fc-O1.

Employing infrared microscopy (IRM) in combination with a pre-trained neural network to visualise and analyse the defect distribution in Cadmium Telluride crystals

While Cadmium Telluride (CdTe) excels in terms of photon radiation absorption properties and outperforms silicon (Si) in this respect, the crystal growth, characterization and processing into a radiation detector is much more complicated. Additionally, large concentrations of extended crystallographic defects, such as grain boundaries, twins, and tellurium (Te) inclusions, vary from crystal to crystal and can reduce the spectroscopic performance of the processed detector.A quality assessment of the material prior to the complex fabrication process is therefore crucial. To locate the Te-defects, we scan the crystals with infrared microscopy (IRM) in different layers, obtaining a 3D view of the defect distribution. This provides us with important information on the defect density and locations of Te inclusions, and thus a handle to assess the quality of the material. For the classification of defects in the large amount of IRM image data, a convolutional neural network is employed. From the post-processed and analysed IRM data, 3D defect maps of the CdTe crystals are created, which make different patterns of defect agglomerations inside the crystals visible. In total, more than 100 crystals were scanned with the current IRM setup. In this paper, we compare two crystal batches, each consisting of 12 samples. We find significant differences in the defect distributions of the crystals.

CdTe sensor configurations for robot assisted photon counting gamma camera

In this work, different Cadmium Telluride (CdTe) sensor configurations are assessed for the usage in a robot assisted portable gamma camera. In the first part, four CdTe sensors, with thickness of 0.45 mm, 1 mm, 2 mm and 3 mm and pixel sizes of 55 μm and 110 μm, are investigated regarding their spectroscopic performance. The photon counting detector Timepix1 is hereby used. The 3 mm CdTe sensor shows increase in count rate up to a factor of 1.25 compared to a 2 mm CdTe sensor, 1.84 compared to a 1 mm CdTe sensor and up to 2.71 compared to a 0.45 mm CdTe sensor in the case of 137Cs. In the second part, the 3 mm CdTe sensor was implemented in a commercially available gamma camera, the iPIX. The system was integrated in the bomb disposal robot and tested in different scenarios. The integrated 3 mm CdTe detector measured 21.5 counts per second emitting from a 60Co source with an activity of 2.8 ± 0.07 Gbq in 20 meters distance in an open environment. The acquisition time was 116 seconds. The angular resolution was sufficient for the user to localize the radioactive isotope inside the test structure.

Comparative spectroscopic analysis, performance and emissions evaluation of Madhuca longifolia and Jatropha curcas produced biodiesel.

In order to fulfil the growing need to replace fossil fuels, investigations exploring the production of biodiesel from agricultural biomass have gained attention. In this study, biodiesels were produced from Madhuca longifolia and Jatropha curcas by means of pre-treatment followed by a two-step acid-base homogeneous catalyst method. These biodiesels were blended with diesel at different percentages. The efficacy of the process was examined using various characterization methods while the efficiency of the produced biodiesels was examined by their engine performance and emission tests. Both Madhuca and Jatropha-based biodiesels exhibited physiochemical properties like that of diesel. Biodiesels were produced by pre-treating with orthophosphoric acid and toluene. The second step involves acid esterification, followed by base transesterification. Raman spectra exhibited C=O stretching at 1725 cm-1 indicating conversion of Madhuca and Jatropha oil into biodiesel. Fourier transform infrared spectroscopy showed a strong presence of fatty acid profile and triglyceride ester linkage at 1744 cm-1. Ultraviolet-visible (UV) spectra confirmed the presence of conjugated dienes in the extracted biodiesels. UV absorbance at 320 nm decreased linearly with blend percentage. 1H and 13C nuclear magnetic resonance (NMR) confirmed the presence of methyl ester moiety at 3.6 δ (ppm) and methoxy carbon at 51.2 δ in biodiesel, distinguishing it from diesel. In the engine performance tests, the variations of brake specific fuel consumption, exhaust gas temperature and brake thermal efficiency versus brake power were studied. The emission tests of different blends were done in terms of carbon monoxide, nitrous oxide and unburnt hydrocarbon. The Jatropha biodiesel exhibited lower mean brake specific fuel consumption, exhaust gas temperature, emitted less carbon monoxide and unburnt hydrocarbon than Madhuca biodiesel. The average decrease in brake thermal efficiency was more in Jatropha biodiesel than Madhuca biodiesel. The present work uses for the first time treatment of ortho phosphoric acid and toluene to produce biodiesel followed by a two-step homogeneous acid-base catalyst method, drastically reducing free fatty acid value.

Repurposing a low-cost commercial Si photodiode as a detector for X-ray and [formula omitted]-ray spectroscopy at temperatures up to 80 °C

A commercial-off-the-shelf (COTS) Si p+-i-n+ photodiode (Hamamatsu S5973), designed for visible and infrared detection, was repurposed for use as a low-cost and readily available detector for photon counting X-ray and γ-ray spectroscopy. The detector was investigated for its spectroscopic performance, while being coupled to a custom-made charge sensitive preamplifier, under the illumination of photons with energies up to 59.54 keV. The detector-preamplifier system was subjected to temperatures from 80 °C to 20 °C. Energy resolutions (Full Width at Half Maximum, FWHM) of 0.66 keV ± 0.05 keV at 5.9 keV, 0.70 keV ± 0.04 keV at 22.16 keV, and 0.74 keV ± 0.06 keV at 59.54 keV, were achieved at 20 °C. The energy resolution deteriorated at 80 °C, reaching a value of 1.8 keV ± 0.1 keV FWHM at 59.54 keV. The results suggested that the performance, in terms of energy resolution, of the currently reported COTS Si detector was better than that achieved with certain purpose-grown wide bandgap detectors at 20 °C and 40 °C and better than that achieved with other repurposed Si detectors at 20 °C, opening new possibilities for applications for the Hamamatsu S5973 detectors and increasing the availability of low cost X-ray and γ-ray spectroscopy instrumentation.

Comparative Spectroscopic Studies on Luminescence Performance of Er&lt;sup&gt;3+&lt;/sup&gt; Doped Tellurite Glass Embedded with Different Nanoparticles (Ag Co and Fe) at 0.55 μm Emission

The spectroscopic performance of Er3+ doped glass at 0.55 mm emission contain different nanoparticles NPs have been comparatively evaluated. Glass containing 1.0 mol % of Er3+ doped with different NPs (Ag, Co and Fe ) have been prepared using melt quenching technique. X-ray diffraction analysis reveals the all the prepared samples are amorphous. The UV-Vis absorption spectra of all glasses show several prominent peaks at 525 nm, 660 nm, 801nm, 982 nm and 959 nm due to transition from ground state 4I15/2 to different excited of 2H11/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2. The emission of Er3+ at 0.55 mm for glass contain Ag NP shows significant enhancement about 3 folds up to 0.6 mol%. On the other hand, the emission of Er3+ at 0.55 mm for glass containing Fe NPs and Co NPs intensely quench probably due to the energy-transfer from Er3+ ion to NPs and magnetic contributions.