Mylar Film Research Articles

Study in the Extreme UV Range of the Spectral Transmission of Nickel Plasma Created under the Effect of an X-Ray Pulse of the Z-Pinch

Spectral properties of the high-temperature plasma obtained by exposing a nickel layer to a source of high-power X-ray radiation (a power of 6–10 TW with a duration of 7–10 ns) based on a Z-pinch, formed during implosion of tungsten multi-wire arrays at the Angara-5-1 facility, are studied. In this case, the Z-pinch radiation heats the target and turns it into the hot plasma, and the same radiation probes the target plasma to determine the spectral dependence of the transmission of this plasma. An original scheme is proposed for measuring the incident, transmitted and self-emission of a target simultaneously in one experiment in the frame mode using a grazing incidence diffraction spectrograph. Using laser shadow imaging, experimental data are obtained on the velocity of the plasma expansion on the irradiated and back sides of the target, which reached 100 km/s. Targets made of thin Ni layers deposited on a mylar film are studied. An irradiationinduced multiple increase in the transmission of the target plasma in the EUV range is observed compared to the transmittance of the target in the cold state. The dependence of the absorption spectrum of the plasma and the accompanying self-radiation of the target on the power and shape of the heating pulse is studied. The measurement results are compared with numerical calculations performed using the RALEF-2D two-dimensional radiation code, which has been repeatedly used previously to simulate similar experiments. The shape of the spectral dependence of the transmission in the experiment and calculation is similar in the range of ∼30–200 Å, but the model plasma transmission (∼0.8–0.9) is higher than that obtained using a spectrograph and X-ray multi-frame photography (∼0.5–0.6).

Collimation principles of a hollow X-ray microbeam for high-contrast cytoplasm irradiation.

A Monte Carlo simulation was used to assess the performance of a collimated hollow X-ray microbeam for subcellular cytoplasm irradiation. A high-Z coaxial collimation structure with an inner core for nucleus shielding was investigated. Two key performances, the extraction efficiency (cytoplasm dose per unit incident fluence) and the dose contrast (cytoplasm-to-nucleus dose ratio), were evaluated regarding the influences of the material, geometry and physical arrangements of the collimator, target dish and incident beam source. Simulation results demonstrate that a gold coaxial structure with a practical collimation geometry of a 1-mm length, 10-μm inner diameter and 200-μm outer diameter, with the top exit closely attached (with a minimized air gap) to the bottom of a cell dish with a 3-μm thick Mylar film is recommended for cytoplasm irradiation of adherent mammalian cells. For a synchrotron source in the energy range < 10keV, a dose contrast of approximately 100 can be achieved. For a bremsstrahlung source <30-kV tube voltage, a dose contrast of approximately 50-100 can still be achieved. General principles are summarized with further explanations of the performance of the hollow X-ray microbeam.

A novel method for efficiently measuring the non-proportionality of scintillators between light output and alpha particle energies from 1.8 MeV to 5.2 MeV

It is known that scintillators exhibit non-proportional behavior between light output and the energy of gamma photons or beta particles. However, the non-proportionality between light output in scintillators and the energy of alpha particles has not been extensively measured, likely due to the challenges associated with preparing alpha particles with varying energies. To address this issue, we propose a novel method to modulate the energy of alpha particles using an americium-241 (Am-241) source covered with different numbers of Mylar films. By irradiating various scintillators, including GAGG, GGAG, YAP(Ce), and plastic scintillator, with alpha particles of different energies, we measured and evaluated the non-proportional response of these scintillators. We then compared the measured response as a function of incident energy to a simulation, which assumes a proportional response to evaluate the non-proportionality. For all the scintillators tested, non-proportionality was observed; the light output per MeV at 1.8 MeV ranged from 0.60 to 0.81 of the values observed at 5.2 MeV. The non-proportional response was largest for plastic scintillator (0.60) and smallest for GAGG (0.81). We conclude that the proposed method could be an efficient means of measuring the non-proportionality of scintillators between light output and alpha particle energies

Ion acceleration from golden mylar film irradiated by visible ns pulsed laser

AbstractA Pulsed ns laser operating at 532 nm wavelength with 150 mJ pulse energy was employed to irradiate micrometric thick mylar films, from 1 to 100 μm thick, covered by 0.05 μm Au in the back face. Protons and light ions have been accelerated by the electric field developed in the non‐equilibrium plasma by the laser pulse in a vacuum at an intensity of the order of 1010 W/cm2. Time‐of‐flight technique, obtained using a Faraday cup and a fast storage oscilloscope, is employed to measure the ion velocity, energy, and yield emitted in backward and forward directions. The yield of the emitted plasma photons is also evaluated. Two ion collectors are used in opposite directions to measure the plasma radiations emitted in backward and forward directions. Data analysis is based on the Coulomb‐Boltzmann‐shifted (CBS) distribution function. The target ablation yield is evaluated in the order of 3.5 μm per laser shot.

The development of segmented electrode thin-film parallel plate avalanche counter (PPAC)

In order to improve the counting rate and position resolution of the Parallel Plate Avalanche Counter (PPAC) within the Compact Spectrometer for Heavy Ion Experiment, a new strip film-structured PPAC has been developed. The developped PPAC detector consists of three layers of film electrodes. The upper and lower layers which serve as the anodes are comprised of self-developed strip film electrodes, oriented perpendicularly to each other. The middle layer utilizes double-sided aluminized Mylar film as the cathode. There is a 3 mm gap between each layer, and the detector has an effective area of 76 mm× 76 mm. Operating in a low-pressure environment with isobutane gas as the working medium, the performance of the PPAC has been measured using a 5.486 MeV α radiation source. The measurement results indicate that the overall position resolution of the PPAC attains approximately 380 μm, and the position resolution improves to 300 μm when using slit width correction. Finally, the Monte Carlo simulation has been performed to simulate the distribution of electrons generated by the detector's ionization under the same conditions on the anode readout strip. The simulation results closely matches the observed multiplicity of hit anode readout strips in measurement.

Ion acceleration from aluminised mylar film irradiated by visible ns-pulsed laser

A ns-pulsed laser operating at 532 nm wavelength has been employed to irradiate micrometric mylar films (1–100 μm) with an attached 0.1 μm Al film on its back face. Protons and light ions have been accelerated by the electric field developed in the non-equilibrium plasma generated by the laser pulse in a vacuum at an intensity of the order of 1010 W/cm2. The Time-of-flight (TOF) technique, using a Faraday cup (ion collector) coupled to a fast storage oscilloscope, has been employed to measure the ion velocity, energy and yield. The yield of plasma-emitted photons has been also evaluated. Two ion collectors have been used in opposite directions to measure the maximum ion acceleration by the TOF data acquired in backward and forward directions and the photon yield as a function of the target thickness. The evaluation of the ion energy distribution has been based on the Coulomb-Boltzmann-Shifted (CBS) distribution function.

Range and light output measurements of trajectory images in a GAGG plate with different alpha particle energies

An imaging method that utilizes a scintillator plate combined with a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera shows promise for obtaining high-resolution trajectory images. However, it is not yet clear whether the ranges of the trajectory images change with the energy of the alpha particles. Additionally, it remains unclear whether the intensity of the trajectory images is affected by the energy of the alpha particles. To address these questions in our trajectory imaging research, we conducted experiments to capture trajectory images of alpha particles with varying energy levels. To generate alpha particles with different energies, we modulated the energy using an americium-241 (Am-241) source covered with varying numbers of Mylar films. With this alpha source and imaging system, we successfully captured trajectory images with different alpha particle energies and were able to assess the ranges and intensities of these trajectories at various energy levels. The estimated ranges from the measured images with different alpha particle energies closely matched the results obtained through simulations. However, it's worth noting that the light output, as evaluated for the measured trajectory images, was slightly lower than the simulated results at lower energy levels probably due to the non-proportionality of the GAGG plate with respect to alpha particle energies.

Estimate of the random match frequency of acquired characteristics in footwear: Part II — Impressions in dust

This study serves as Part II of an investigation into the random match frequency of randomly acquired characteristics (RAC-RMF) in footwear evidence. In Part I, RAC-RMF was estimated in a dataset of laboratory-simulated crime scene impressions deposited in blood. For Part II, a second dataset was created composed of impressions deposited in dust on paper or tile, with the latter lifted using gelatin or Mylar film. A total of 1,513 RACs were identified from more than 160 dust impressions and compared to RACs with positional similarity in test impressions from 1,299 non-mated outsoles. RACs of any size deposited in dust exhibited a 31% decrease in shoes with non-zero RAC-RMFs as compared to their mated test impressions, while those deposited in blood exhibited a 45% increase. When only considering shoes with at least one RAC deemed forensically-reliable (length ⩾ 2.8 mm), 3.1% of shoes contributing dust impressions and 3.4% of shoes contributing blood impressions exhibited relative RAC-RMFs at a value ⩾ 0.0008. Although each dataset resulted in a comparable rate for encountering non-zero RAC-RMFs, the estimate for dust was based on twice the number of RAC comparisons (154,477) than those performed when assessing blood (77,566). While these results are considered specific to the non-mated impressions and methods of analysis described herein, and continued work is required before rates can be fully understood and reported in forensic casework, this study encountered non-zero RAC-RMFs for shoes exhibiting at least one forensically-reliable RAC at a more frequent rate than any estimates previously reported.

Gadolinium dose enhancement determination by unlaminated EBT3 films irradiated with 192Ir brachytherapy source

In this work, Gafchromic® EBT3 films were carefully delaminated and resealed with a thin mylar film of 12 μm for implementing accuracy measurements of Gd dose enhancement by a192Ir brachytherapy source. The intervened dosimeters were previously characterized in terms of their quality intervention (mechanical damage and dosimetry modification). The dose enhancement measurements were implemented in a phantom formed by a set of acrylic slabs of 30 × 30 × 0.5 cm3 machined to contain in the central axis 2 vials of 1.25 × 1.25 × 4.5 cm3 which were filled with a 20 mg/ml solution of Gd agents and with water simulating a tumoral phantom doped and undoped with Gd. In the center of the phantom, a machined acrylic slab was placed to introduce the 2.5 mm flexible guide of GammaMedplus iX equipment to position the source. Fragments of delaminated and resealed EBT3 of 0.9 × 4 cm2 were placed inside the second vial and 0.5 cm away from it, at 1.95 cm and 3.55 cm from the radioactive source respectively, to measure simultaneously the tumor dose enhancement and the radiation shielding produced at a proximal zone. CT images of the phantom were taken to prescribe 5 Gy to 1.95 cm (EBT3 film position) using a Varian BrachyVision™ planning system. Films were read out by a flatbed scanner Epson V750 PRO, 48 h after irradiation. The measurements in both tumor and healthy tissue were repeated ten times in each condition to analyze the uncertainties of the complete experimental realization. The results showed variations in the response of the intervened dosimeters, less than 1.7% for the range of interest and average fluctuations in the readout of 4.6%. The implemented dosimeter showed the feasibility of measuring dose enhancement by 192Ir source of 13 ± 7% for the concentration studied. Additionally, radiation shielding up to 6% was obtained, consistent with what has been reported in the literature.

Static structural and aerodynamics analysis of 3D printed flapping wing mechanism of butterfly inspired ornithopter

The wing flapping motion of butterfly is more straight forward, and its wing morphology is simple. The wingspan is also large enough to make it as a mid-size ornithopter. Based on these reasons, the ornithopter based upon the morphology of butterfly is studied. The objective of this three-dimensional numerical study is to investigate the butterfly ornithopter for its aerodynamic parameters for varied angle of attacks (-6° to 6°) and perform static structural analysis on the 3D printed flapping wing mechanism. The materials chosen for the wing is polypropylene fumarate, carbon fibre rods and Mylar films. The investigations are carried out using ANSYS Mechanical Workbench and ANSYS Fluent. The shear stress is evenly distributed throughout the wing structure for both the applied load conditions. Moreover, the maximum values of equivalent stress and equivalent elastic strain is observed in local concentrations at the position where the Mylar film material wing membrane is connected to the carbon fibre rod. The deformation pattern is maximum at the wingtips (0.08569 for pressure 4.8 Pa; 0.067697 for pressure 3.8 Pa) and minimal near the support sections. The maximum lift with minimum drag is observed at angle of attack + 2°.

Biocompatible Piezoelectric Polymer Poly(Lactic Acid)-Based Stethoscope for Wearable Health Monitoring Devices

With the development of wearable devices and the Internet of Things (IoT), there is a growing demand for portable and comfortable human health monitoring devices. Because of the advantages of biocompatibility, relatively large piezoelectric coefficients, and nonpyroelectricity, poly(L-lactic acid) (PLLA) polymers have been greatly utilized in the applications of tissue engineering, sensors, and energy harvesting devices. In this investigation, the PLLA film was fabricated for the first time for real-time wearable stethoscope and pulse wave sensor applications. First, the stretched PLLA film was glued onto a Mylar film as the active layer of the PLLA film-based stethoscope (PFS) and pulse sensor device. After the PFS device was measured in a semianechoic chamber, the device showed a sensitivity of –53.4 dB at 1 kHz and it also exhibited a stable frequency response in the range of 100 Hz–4 kHz. In addition, the PFS device showed an output voltage of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 90 mV when measuring the heart rate and pulse signal of an adult volunteer. Furthermore, the PFS device was integrated a portable stethoscope system, which can detect a clear pulse signal and send it to a data collection application designed in a cellphone. The biodegradability, stable frequency response, and temperature stability indicate the great potential of PFS device for wearable human health monitoring devices.

Untethered Flight of a 270 mg Microrobot Powered by Onboard Energy

It is challenging for microrobots to fly using onboard energy due to the relatively heavy power supplies and inefficient actuators that are limited to a small size (mass less than 1000 mg and wingspan less than 100 mm). Inspired by the movement of jellyfish in nature (Physophora hydrostatica), herein, a microscale aerial vehicle FlyJelly is introduced, powered by onboard energy to achieve untethered flight. FlyJelly uses a balloon filled with helium to overcome self‐gravity and an actuator powered by electrostatic power to generate thrust. The balloon, heat sealed with two gold‐covered Mylar films, weighs 95.56 mg, provides 257.9 mg of buoyancy when filled with helium, and stores 19.457 × 10−3 J of energy when powered by 2400 V of direct current. The electrostatic actuator is composed of multiflapping units arranged radially and symmetrically, consuming only 0.3370 mW of power but generating a thrust of 0.2271 mN to drive the vehicle for flight. Benefiting from a design of distributed propulsion, FlyJelly is highly reliable and continues to work well even after the actuator is damaged. The milligram‐level weight, untethered flight with onboard energy, and high reliability make the prototype suitable for development as a long‐term remote exploration and search‐and‐rescue mission.

New trapezoid-shaped Frisch-grid ionization chamber for low-energy particle measurements

A new trapezoid-shaped Frisch-grid ionization chamber (TFG-IC) has been built as a part of a varDelta {E}-E telescope system for the detection and identification of charged particles at energies down to a few MeV. To study the effect of the drift electric field uniformity, two types of sealed windows, namely a pair of SSA (split-strip aluminized mylar film) and a pair of DSA (double-sided aluminized mylar film) sealed windows have been investigated. The detector’s performances were studied using a standard ^{241}Am source at different gas pressures, and the total energy-deposit resolution achieved is about 1.1%(FWHM). The varDelta {E}-E telescope, which was composed of TFG-IC and a DSSSD (double-sided silicon strip detector), has been tested using a three-component alpha source and the ^{241}Am source under laboratory conditions. The results show that the energy resolution with the SSA sealed windows which provide uniform drift electric field has a smaller fluctuation than that with the DSA ones; the fluctuations are about 1% and 4% for the former and the latter, respectively. Simulations using the COMSOL software also confirmed the electric-field distortion at the edge of the detector with the DSA windows. A correlation curve between energy resolution and energy deposit of charged particles at various gas pressures and for two gas species is derived for TFG-IC with the SSA sealed windows using the measurement with the ^{241}Am source. Incorporating the above results, we performed Monte Carlo simulations to evaluate the particle-identification capability of the telescope. The results show that the telescope can be extended to the identification of low-energy particles.

Fixed-target serial crystallography at the Structural Biology Center.

Serial synchrotron crystallography enables the study of protein structures under physiological temperature and reduced radiation damage by collection of data from thousands of crystals. The Structural Biology Center at Sector 19 of the Advanced Photon Source has implemented a fixed-target approach with a new 3D-printed mesh-holder optimized for sample handling. The holder immobilizes a crystal suspension or droplet emulsion on a nylon mesh, trapping and sealing a near-monolayer of crystals in its mother liquor between two thin Mylar films. Data can be rapidly collected in scan mode and analyzed in near real-time using piezoelectric linear stages assembled in an XYZ arrangement, controlled with a graphical user interface and analyzed using a high-performance computing pipeline. Here, the system was applied to two β-lactamases: a class D serine β-lactamase from Chitinophaga pinensis DSM 2588 and L1 metallo-β-lactamase from Stenotrophomonas maltophilia K279a.

Visibly Transparent and Infrared Reflective Coatings for Personal Thermal Management and Thermal Camouflage

AbstractTailoring thermal radiation using low‐infrared‐emissivity materials has drawn significant attention for diverse applications, such as passive radiative heating and thermal camouflage. However, the previously reported low‐infrared‐emissivity materials have the bottleneck of lacking independent control over visible optical properties. Here, a novel visibly transparent and infrared reflective (VTIR) coating by exploiting a nano‐mesh patterning strategy with an oxide–metal–oxide tri‐layer structure is reported. The VTIR coating shows simultaneously high transmittance in the visible region (&gt;80% at 550 nm) and low emissivity in the mid‐infrared region (&lt; 20% in 7–14 µm). The VTIR coating not only achieves a radiative heating effect of 6.6 °C for indoor conditions but also enables a synergetic effect with photothermal materials to keep human body warm at freezing temperatures for outdoor conditions, which is 10–15 °C warmer than normal cotton and Mylar film. Moreover, it demonstrates an excellent thermal camouflage effect at various temperatures (34–250 °C) and good compatibility with visible camouflage on the same object, making it ideal for both daytime and nighttime cloaking. With its unique and versatile spectral features, this novel VTIR design has great potential to make a significant impact on personal heat management and counter‐surveillance applications.

Ordinary and Extraordinary Complex Refractive Indices Extraction of a Mylar Film by Transmission Spectrophotometry.

A new spectrophotometric technique for the determination of both ordinary and extraordinary complex refractive indices (CRIs) of a stretched polyethylene terephthalate (Mylar) film is proposed. The sample was placed between two identical polarizers, and the transmission spectra of two different configurations (incident polarization parallel and perpendicular to the Mylar film optical axis) were recorded. Ordinary and extraordinary complex refractive indices are then extracted by fitting the experimental spectra with a theoretical model that we had elaborated in advance. A new formula for transmittance dispersion, based on the Fresnel’s coefficients formalism and using the Cauchy model, was derived to describe n and κ wavelength dependence. The suggested theoretical model succeeded in reproducing the Mylar transmission spectra across the entire visible spectral range (400, 750 nm) for both configurations, and the retrieved dispersion curves of the refractive indices, extinction coefficients, and the birefringence are comparable to results found in the literature. The proposed method is fast, straightforward, easy to set up, and cost-effective. It proved to be an excellent alternative to more conventional methods such as spectroscopic ellipsometry.

Linear retardance and diattenuation dispersion measurements of anisotropic medium with Jones calculus based spectrometric technique

A white light spectrometric technique based on the Jones Calculus (JC) formalism using channelled transmission spectra has been developed to measure the linear retardance (LR) and diattenuation (LD) of a Mylar film, widely used for liquid crystal display devices. The sample was placed between two identical polarizers and the channelled spectra of two different configurations (parallel and crossed) were recorded. Transmitted light intensity data over a broad visible spectral range of both channelled spectra were then combined in order to derive the dispersion of retardance and diattenuation of the Mylar film with respect to the wavelength. This technique is fast, easy to setup, and straightforward; and the proposed model, based on the Jones formalism, offers an intuitive and simple calculation, particularly because, unlike other models based on the Mueller calculus, Jones matrices have simpler properties and are more easily manipulated and interpreted. Moreover, the technique provides a complete analytical formulation of transmitted light intensity taking into account the diattenuation defect in both polarizers and sample.

Development of an innovative external (in air) Particle Induced Gamma-ray Emission method for rapid non-destructive determination of isotopic composition of boron in “As received” boron based ceramic neutron absorbers

Boron is an important element in nuclear reactor technology due to its high neutron absorption cross section of 10B isotope. Isotopic composition of B (IC, 10B/11B atom ratio) determination in finished neutron absorbers is a necessity under chemical quality control (CQC). We report an innovative greener method for rapid and non-destructive approach of isotopic composition determination of B in “as received” boron based ceramic neutron absorbers including boron carbides and hexa-borides by external (in air) Particle Induced Gamma-ray Emission (PIGE) using 3.5 MeV proton beam. It involves irradiation of “as received” powder samples wrapped in a thin Mylar film and measurement of prompt gamma rays at 429, 718 and 2125 keV from 10B(p,αγ)7Be, 10B(p,p’γ)10B and 11B(p,p’γ)11B, respectively, using a HPGe detector system. The method was standardized with natural and enriched B4C powders. For validation, the results of isotopic composition obtained from “as received” samples were compared with that obtained from pellet samples using both external and vacuum chamber PIGE methods. IC values obtained for natural to 10B enriched samples (19.8–67 atom % of 10B) are very encouraging with 1–2% and 0.3–0.7% uncertainties from single and replicate sample experiments. The method is truly non-destructive as the samples can be returned back as such after the experiment as they are not radioactive. Compared to existing PIGE method for isotopic composition of B, the developed method keeps promise for wide applications as it is simple, sensitive and rapid and it does not require vacuum, pellet preparation with a binder, exact mass of the sample and beam current measurement.

Quantitative light element analysis: Complementary IBA methods for H to O detection using an external proton beam

A new setup for quantitative light element analysis of thin films using a 2.50–2.72 MeV external proton beam under atmospheric conditions is described. This setup simultaneously performs backscattering spectrometry (BS) and p-p coincidence elastic recoil detection analysis (C-ERDA) in transmission. BS utilizes a highly non-Rutherford cross-section for profiling of e.g. C, N and O whereas C-ERDA is used to measure H concentration profiles in foils of up to 12.5 μm in thickness. To validate the method, thin Ti layers are deposited on 200 nm Si3N4 membranes and loaded with H. The method shows an expected increase of H concentration in the films with longer loading times. Nuclear reaction analysis (NRA) for Li detection in LiMn2O4 samples is undertaken to test the possibility of using complementary proton scattering techniques simultaneously. A Li depth resolution of around 250 nm can be achieved. Radiation damage to Mylar and Kapton films is investigated and the radiation resistance of Kapton demonstrated.

Imaging of a High-Power Millimeter Wave Beam Using a Millimeter Wave-Induced Gas Breakdown Initiated by a Metal-Dielectric Screen

A semiquantitative technique for imaging of high-power millimeter wave (MMW) beam using visible light from the plasma of an MMW-induced gas breakdown, which was initiated by a metal-dielectric (MD) screen, is discussed. The design of the gas breakdown sensor for imaging of the wave beam is presented. A plane MD screen was placed in a shallow airtight chamber with a transparent window of a thin mylar film. The chamber was filled with gas at a near atmospheric pressure. An MMW-induced breakdown in air, nitrogen, helium, and krypton, initiated by an MD screen, has been experimentally studied. In the experiments, a high-power 250-GHz pulsed gyrotron served as the source of MMWs. In a chamber filled with noble gases, bulk plasma was formed at an MMW intensity above the gas breakdown threshold. A single-pulse wave beam was imaged using a profile of the flux density of light from the breakdown plasma in helium and krypton. It was shown that using the presented technique, one can determine the position of the intensity maxima and the beam profile of an MMW beam in the range from one to two threshold intensities of an MMW-induced gas breakdown initiated by an MD screen.