Makrofol Polycarbonate Research Articles

Nonlinear Calibration and Temperature Sensitivity of Makrofol Solid-State Nuclear Track Detectors for Radon Measurement

A key characteristic of a solid-state nuclear track detector (SSNTD) is that as more alpha tracks accumulate on the detector, the likelihood of track overlap will increase, making it difficult to distinguish individual events. This article presents the calibration of an in-house SSNTD using a Makrofol polycarbonate detector and electrochemical etching. The calibration employs a nonlinear log-logistic quantile function, which is nearly linear at low exposures but accounts for the reduced efficiency at high exposures due to overlapping alpha tracks. The function can be fitted to calibration measurements very accurately, eliminating systematic errors previously associated with the method at certain radon exposures. This article explores the uncertainties and detection limits associated with the calibration and outlines methods for their evaluation. Additionally, it includes a preliminary discussion on the method’s sensitivity to temperature.

Optical properties of Makrofol under various alpha fluences

The optical properties of Makrofol samples are investigated under various fluences of alpha exposure (2 MeV at 5×102, 103, 5×103, 104 , 5×104, 105, 5×105 and 106 alphas.cm2 alongside the unirradiated ones (pristine). Several analyses, including UV–visible, diffused reflectance spectroscopy (DRS), photoluminescence (PL), Fourier transform infrared/attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and sessile drop technique, are carried out to reveal the subsequent variations in the optical features of the irradiated polymer foils. The optical transmittance of the irradiated samples notably increases against the pristine ones, while it undergoes a+ plateau over various fluences. Additionally, the scattering events are more prominent in pristine samples over UV (240–400 nm) and IR (900–1040 nm) compared to the irradiated ones. While there are negligible physical alterations on the polymer surface, the photoluminescence emission gradually decreases with increasing alpha fluences in the irradiated samples mainly due to the reduction in the population of the aromatic rings. The latter is also verified by means of the surface chemical analyses such as XPS, FTIR-ATR and sessile drop/contact angle measurements. XPS reveals that the alpha particles give rise to the successive scissions of C–C and CO bonds and the consequent recombination events in the form of C–O bonds, evidenced by the changes in their abundance percentages. Concurrently, the surface hydrophilicity initially elevates up to a certain fluence and then reduces at higher fluences, indicating a couple of competitive mechanisms are involved in the context of the interactions of the alpha particles with the Makrofol polycarbonate (PC).

Radiation Induced Changes in Makrofol PCVM Polycarbonate

Makrofol PCVM is a sort of Makrofol polycarbonate solid state nuclear track detector. It is worth mentioning that this paper is almost the first one that deals with the modification of the optical properties of this type of Makrofol under the effect of laser radiation. Samples from Makrofol PCVM were exposed to infrared pulsed laser with different fluences ranging from 15 to 125 J/cm2 . UV spectroscopic technique was used to obtain knowledge about the optical parameters that describe the samples under study. The changes of Urbach energy (Eu ), optical band gap (Eg ) and refractive index (n) with the laser fluence were investigated. Both Eu and n increased with increasing the fluence up to 125 J/cm2 , associated with a decrease of Eg values. These trends were assigned to the predominance of chain crosslinking that damaged the crystalline portion in the Makrofol polymer. Additionally, we used the CIE technique to calculate the color differences between the noncoloured pristine and the irradiated samples. The crosslinking created color centers that produced color difference between the exposed films and the uncolored pristine Makrofol film. The color difference was significant as the values of ΔE were greater than 5. This optimized the Makrofol polymer to be used in dosimetric applications.

Tailoring the structural and optical properties of Makrofol/CdS nanocomposite by gamma radiation

We synthesized nanocomposite (NCP) from Makrofol polycarbonate (PC) and Cadmium Sulfide (CdS) nanoparticles (NPs) by means of ex-situ casting procedure. We used thermalizes procedure to prepare the NPs in the presence of nitrogen gas stream. Rietveld refinement of x-rays records illustrated that the CdS has cubic and hexagonal constitutions. Samples from the PC-CdS NCP were exposed to γ dosages ranging from 20 to 250 kGy. The changes in structure and optical properties of the NCP films were investigated based on the γ dosage. The optical bandgap, refractive index, Urbach energy, optical dielectric parameters, chromaticity coordinates, tristimulus values, color intensity and color intercepts have been calculated and interpreted based on γ dosages. The bandgap decreased from 4.20 to 4.11 eV with increasing the γ dosage due to the domination of crosslinking, which damage the crystalline phase as indicated from X-ray diffraction (XRD). Further, the non irradiated PC-CdS NCP film displayed significant color difference by γ irradiation.

A comparative study of the structural, optical and morphological properties of different types of Makrofol polycarbonate

A comparative study of the structural, optical and morphological properties of different types of Makrofol polycarbonate

Gamma induced changes in Makrofol/CdSe nanocomposite films

We applied an ex-situ casting procedure to prepare a nanocomposite (NCP) from Makrofol polycarbonate (PC) and CdSe nanoparticles. The CdSe nanoparticles were prepared by a thermolysis procedure in the presence of N2 gas flow. Rietveld refinement of x-ray data illustrated that the CdSe adopts a cubic zinc blend structure of 6.057 Å lattice parameter and 2 nm typical grain size. Samples from the prepared NCP were exposed to γ dosages (20 kGy–250 kGy). The modifications induced in the NCP films owing to γ dosages have been studied. The γ irradiation (50 kGy–250 kGy) causes crosslinks that reduce the optical bandgap from 4.15 eV to 3.81 eV, associated with an increase in dielectric parameters and refractive index. This is attributed to an increase in the mass fraction of the disordered regions as specified by x-ray diffraction. The PC–CdSe NCP was found to have a reaction to color modification which makes it suitable for saleable reproduction on a printing press.

Gamma-induced changes in the optical and structural properties of palladium/polycarbonate nanocomposite membrane

Makrofol Polycarbonate (PC) is a polymeric solid-state nuclear track detector (SSNTD) by which various applications can be used in several dosimetric and industrial fields. In this work, nano-sized palladium Pd was prepared and mixed with PC (5 wt.%) to produce nanocomposite films. Samples from the Pd/PC nanocomposite films have been irradiated with gamma doses 20–300 kGy. The modification induced in the optical properties and structure of the Pd/PC nanocomposite samples due to gamma irradiation has been investigated. The increase of Urbach energy, accompanied by a decrease in energy band gap, with the gamma dose indicated that the gamma irradiation up to 300 Gy increases the intermolecular interaction of PC chains and Pd leading to an increase in the disorder in the naocomposite samples. It is well known that the nano-palladium is effective in stabilizing the PC, resulting in the enhancement in both refractive index and intrinsic viscosity with the gamma dose. This leads to a more compact structure of PC due to crosslinking. Additionally, the color sensitivity for the non-irradiated Pd/PC nanocomposite sample showed a significant behavior toward gamma radiation. The color intensity ΔE is the difference in the color between non-irradiated samples and the samples irradiated with various gamma doses. ΔE is increased by increasing the dose till 300 kGy, accompanied by an increase in the yellow color component. Finally, FTIR spectroscopy was performed on the non-irradiated and irradiated samples to correlate the induced changes in Pd/PC nanocomposite with the changes in the function groups.

Gamma-induced changes in some of the structural and optical properties of Makrofol polycarbonate/silver nanocomposites films

ABSTRACTNano-sized silver (Ag) was prepared and mixed with Makrofol polycarbonate (PC) (5 wt%) to produce nanocomposites films. Samples from the PC/Ag nanocomposite films have been exposed to gamma radiation in the dose range of 20–300 kGy. The consequential effect of gamma radiation has been studied using X-ray diffraction, fourier transform infrared spectroscopy and UV spectroscopies and color difference measurements. The results indicate that the gamma irradiation up to ∼150 kGy increases the intermolecular interaction of PC chains and Ag that could be attributed to crosslinking that destroys the ordering structure, giving the polymer more resilience. This was accompanied with a reduction of the optical energy gap and an increase in refractive index. In addition, the color intensity, which is the color difference between the irradiated samples and the non-irradiated one, increases with increasing the gamma dose at the range of 20–150 kGy, accompanied with an increase in the blue and green color components.

A Comparative Study of the Effects of Oxygen Ions Upon the Free Volume and Physico‐Chemical Properties of Makrofol (KG & N) Polycarbonate

SummaryMakrofol (KG & N) polymers are the important class of polycarbonates which are used as solid state nuclear track detectors. The effect of 100 MeV oxygen ions (O7+) on the free volume and physico‐chemical properties of Makrofol (KG & N) polymers were studied. The pristine and irradiated samples were characterized by positron annihilation lifetime spectroscopy, X‐ray diffraction, UV‐visible and FTIR. A comparative study of free volume was carried out from the obtained values of the pristine and irradiated samples of both the polymers. The absorption edges of UV‐visible were found to be shifted towards longer wavelength region. The intensities of the various absorption bands of the infrared spectra were found to be modified; which indicated the changes in the chemical properties of the exposed samples.

Irradiation influence on Mylar and Makrofol induced by argon ions in a plasma immersion ion implantation system

Mylar and Makrofol polycarbonate polymers were irradiated by Ar ions in a plasma immersion ion implantation (PIII) system. The surface wettability of both polymers was investigated by employing the contact angle method. The measured contact angles were found to depend on the surface layer properties. Good wetting surfaces were found to depend not only on surface roughness but also on its chemistry that analyzed by Fourier transform infrared (FTIR) spectroscopy. Surfaces topography and roughness was investigated and correlated to their surface energy which studied with the aid of acid-base model for evaluating the improvement of surface wettability after irradiation. PIII improves polymers surface properties efficiently in a controllable way.

Gamma Radiation Induced Modifications on Physicochemical Properties of Makrofol (KG and N) Polycarbonate

ABSTRACTMakrofol (KG and N) polycarbonates (PCs) are the most versatile solid‐state nuclear track detectors. These polymers were exposed to gamma radiation of doses ranging from 250 to 1000 kGy. The pristine and exposed samples were characterized by X‐ray diffraction (XRD), UV–vis spectrophotometry, and Fourier transform infrared spectrophotometry for the structural, optical, and chemical studies, respectively. The XRD studies showed that crystallite size for exposed samples of makrofol‐KG PC decreased from 64.7 to 57.9 Å and for makrofol‐N PC it increased from 19.1 to 21.1 Å. The band gap energy decreased from 4.40 to 4.07 eV for makrofol‐KG and from 4.26 to 3.83 eV for makrofol‐N after the gamma exposure. The number of carbon atoms per conjugation length as obtained from UV–vis studies was increased in both cases. The activation energy showed fluctuations for exposed samples of both polymers. The intensity of various absorption bands of the infrared spectra decreased at some doses for both the PCs, indicating the change in the chemical properties of the exposed samples.

Structural Changes of Makrofol Polymer due to Argon Ion Beam Irradiation

Structural Changes of Makrofol Polymer due to Argon Ion Beam Irradiation Argon ion beam extracted from cold conical cathode ion source has been used to induce changes in the structural properties of makrofol polycarbonate specimens. The feasibility of enhancing the physical properties of Makrofol polycarbonate detector using argon ion beam irradiation has been investigated, along with, the effects of irradiation on the structural properties. Samples from Makrofol Polycarbonate sheet of 300 μm thickness were exposed to an argon ions beam in the fluence range 0.5×1017 – 0.5×1019 ions/cm2. Fourier Transform Infrared (FTIR) Spectroscopy was used to study the modifications in the chemical and physical structure of Makrofol polycarbonate specimens. It has been found that the intensities of the characteristic absorption bands were affected predominantly with the increasing ion dose and indicating degradation followed by cross linking of this polymer by argon ions.

On the determination of the time-scale of three-fragment emission in the 12.7 GeV 4He+238U reaction using the polycarbonate track detector Makrofol

The timescale for emission of three fragments (Z⩾8) in the 12.7 GeV 4He+238U reaction has been studied using a sandwich configuration of the Makrofol polycarbonate track detector. In events with varying multiplicity of heavy fragments (Z>20), the differences of the correlation functions for relative angle and relative velocity between pairs of fragments have been studied in order to determine the fragment emission timescale. A sequential decay mechanism for the excited residual nuclei was found to be consistent with experimental data. It was determined that the fragment emission time decreased with decreasing multiplicity of heavy fragments from 1200±80 fm c−1 for events with two heavy fragments to 400±50 fm c−1 for events with one heavy fragment.

Time-scale analysis of three-fragment emission in the 12.7 GeV 4He + 197Au reaction

The time-scale for emission of three fragments ( Z ≥ 8) in the 12.7 GeV 4He + 197Au reaction has been studied using a sandwich configuration of the Makrofol polycarbonate track detector. In events with different multiplicity of heavy fragments ( Z > 20), the differences of the correlation functions for relative angle and relative velocity between pairs of fragments have been studied in order to determine the fragment emission-time scale. A sequential decay mechanism for the excited residual nuclei was found to be consistent with experimental data. It was determined that the fragment emission-time decreased with decreasing multiplicity of heavy fragments: from 1000 fm/c for events with two heavy fragments, through 300 fm/c for events with one heavy fragment, to 40 fm/c for events with no emission of heavy fragments.

Effect of neutron dose on the structural properties of Makrofol polycarbonate

The effect of neutron dose on the structural properties of a Makrofol polycarbonate detector has been studied. Samples of Makrofol were classified into three main groups. The first, second and third groups were irradiated with neutrons in the dose ranges of 0.01–0.08, 0.1–0.8 and 1.0–8.0 Sv, respectively. The structural modifications in the neutron irradiated samples were studied using X-ray diffraction and Fourier-transform infrared spectroscopy. In addition, the effect of neutron dose on the intrinsic viscosity of the liquid samples, as a measure of the mean molecular mass of the Makrofol polymer, was studied. An increase in the –OH groups was observed at dose ranges of 0.01–0.04 and 3.21–8.0 Sv due to the degradation of carbonate group and the –H abstraction from the polymer backbone to form hydroxyl groups. This indicates that the degradation is dominant at these dose ranges that enhance the degree of ordering in the irradiated samples. On the other hand, irradiation in the dose range 0.04–3.21 Sv was characterized by a dominant crosslinking mechanism that led to an increase of the amorphous phase and average molecular mass.

Modification induced by alpha particle irradiationin Makrofol polycarbonate

AbstractMakrofol DE 1‐1 CC polycarbonate samples were exposed to alpha particles of initial energies at levels between 5.1 and 34 MeV. The modifications induced in polycarbonate samples due to the alpha particle irradiation have been studied through different characterization techniques such as X‐ray diffraction (XRD), infrared spectroscopy, intrinsic viscosity, and color difference studies. The infrared spectroscopy indicated that the intensities of the characteristic absorption bands decrease with increasing the deposited alpha energy in the range 5.1–8.4 MeV, indicating that the degradation is the dominant mechanism at this range. At the same time, an increase in the OH groups was observed at the same energy range 5.1–8.4 MeV due to the degradation of carbonate group and the H abstraction from the polymer backbone to form hydroxyl groups. The degradation reported by IR spectroscopy enhanced the degree of ordering in the degraded samples as revealed by XRD technique. Additionally, this degradation decreases the intrinsic viscosity from 0.56 to 0.43 at 35°C, indicating a decrease in the average molecular mass. The non irradiated Polycarbonate polymer is nearly colorless. It showed significant darkness sensitivity towards alpha particle irradiation, indicated by an increase in the color intercept L* from 33.6 to 36.7. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Production of ternary events in [formula omitted], Bi and Au reactions at 8.8 GeV

Events with three fragments with Z ⩾ 8 in the interactions of 8.8 GeV 4He with U, Bi and Au nuclei are examined using the Makrofol polycarbonate track detector. The sandwich technique is used to enable a direct observation of the multiply charged fragment emission by a single nucleus. Fragments produced in these events are identified and an event-by-event model-free analysis is performed in order to separate different production mechanisms. A classification scheme based on the multiplicity of intermediate-mass fragments 8 ⩽ Z ⩽ 20 is used in order to identify events belonging to the different reaction channels. In the interactions of 4He with U, about 70% of ternary events are registered with the multiplicity of intermediate-mass fragments M IMF obs = 0 , 1 , while in the interactions of 4He with Au, about 60% of ternary events are registered with M IMF obs = 2 , 3 . The analysis shows that these two groups of ternary events are produced by different reaction mechanisms. The cross-sections and experimental features are determined for the various reaction mechanisms, and their variation with the target mass has been investigated.

Effect of gamma and laser radiations on the thermal properties of Makrofol nuclear track detector

A study of the modification possibility of the thermal properties of Makrofol polycarbonate solid-state nuclear track detector using gamma and laser radiations has been carried out. Samples from 300 μm thickness Makrofol sheets were classified into two main groups. The first group was irradiated with gamma doses at levels between 50 and 400 kGy, whereas the second group was exposed to infrared laser radiation with energy fluences at levels between 0.5 and 15 J/cm2. Non-isothermal studies were carried out using thermo-gravimetric analysis (TGA) to obtain the thermal activation energy of decomposition for the Makrofol detector. The results of TGA indicate that the Makrofol samples decompose in one main weight loss stage. Also, the irradiation of Makrofol polymer with gamma doses in the range 135–300 kGy or the exposure to laser energy fluences at levels between 8.3 and 15 J/cm2 leads to further enhancement of the thermal stability of the polymer samples due to the cross-linking phenomenon. This suggests that gamma radiation could be a suitable technique for producing a plastic material with enhanced properties that can be a useful candidate for high-temperature applications. In addition, the variation of transition temperatures with the gamma or laser doses has been determined using differential thermal analysis DTA. The results indicate that the irradiation with gamma in the dose range 50–135 kGy or the exposure to laser energy fluences at levels between 8.3 and 15 J/cm2 decreases the melting temperature of the Makrofol samples, and this is most suitable for applications requiring the molding of this polymer at lower temperatures.

Production of heavy fragments in the fission mass region in 12C+U, Bi, Au and Ag reactions at 26.5 GeV

Formation of heavy fragments in the fission mass region in the interaction of 26.5 GeV C 12 with U, Bi, Au and Ag is studied using a sandwich configuration of the Makrofol polycarbonate track detector. Events in which at least one heavy fragment in the fission mass region is detected are analyzed. Fragments produced in these events are identified and an event-by-event model-free analysis is performed in order to separate different production mechanisms. We have identified the events produced in fission, deep spallation and fragmentation processes. The cross sections and experimental features are determined for these reaction mechanisms, and their variations as a function of the target mass have been investigated. The results show that in the interactions of C 12 with U the dominant process is fission, while in the interactions of C 12 with lighter target nuclei the dominant processes are deep spallation and fragmentation.

Radiation-induced changes in some SSNTDs

A comparative study of the effect of fast neutrons and alpha particles on the color changes of some solid state nuclear track detectors was performed. Samples from CR-39 diglycol carbonate and Makrofol polycarbonate were classified into two main groups. The first group was exposed to neutrons of energies in the range between 4.4 and 19.2 MeV, while the second group was irradiated with alpha particles of initial energies in the range between 5.1 and 34 MeV. The transmission of these samples in the wavelength range 200–2000 nm, as well as any color changes, was studied. A characteristic transmission band with different intensities in the wavelength range 200–2000 nm was observed when the samples were exposed to alpha particles, while the interaction of fast neutrons on these detectors, CR-39, may lead to the appearance of new transmission bands at some particular wavelengths. Using the transmission data, both the tristimulus and chromaticity coordinate values were calculated. In addition, the color differences between the non-irradiated sample and those irradiated with different neutron or alpha doses were calculated. The results indicate that both CR-39 and Makrofol detectors acquire color changes under fast neutrons or alpha particles irradiation, but the Makrofol detector has more response to color change than CR-39.