Irradiated Foils Research Articles

Comparison of irradiated foil measurements with activation calculations and HPGe simulations

Theoretical activation calculations for Fe, Ni, and stainless steel foils were compared against irradiated foil measurements from a critical assembly. Calculated/experiment values spanning 0.62–1.31 showed that the restricted approach used here is insufficient for experiment planning, with the collapsed cross-section being the primary source of error. The effect of decay time on gamma-ray spectroscopy measurement reliability was investigated using a Monte Carlo HPGe detector model. Simulations showed no correlation with decay time, absent interferences. Specific interferences for Fe-59 (Ni) and Co-60 (stainless steel) activation product ratios suggested optimal measurement windows having respective decay times of 9–11 days and 4–7 days.

Ion track etching revisited: I. Correlations between track parameters in aged polymers

Abstract Some yet poorly understood problems of etching of pristine and swift heavy ion track-irradiated aged polymers were treated, by applying conductometry across the irradiated foils during etching. The onset times of etchant penetration across pristine foils, and the onset times of the different etched track regimes in irradiated foils were determined for polymers of various proveniences, fluences and ages, as well as their corresponding etching speeds. From the results, correlations of the parameters with each other were deduced. The normalization of these parameters enables one to compare irradiated polymer foils of different origin and treatment with one another. In a number of cases, also polymeric gel formation and swelling occur which influence the track etching behaviour. The polymer degradation during aging influences the track etching parameters, which differ from each other on both sides of the foils. With increasing sample age, these differences increase.

Laser effects on graphene oxide irradiated in high vacuum

ABSTRACTGraphene oxide (GO) foils were irradiated by using different fluences of an infrared nanosecond pulsed laser and characterized before and after the laser irradiation. The produced laser ablation was investigated as well as the generated plasma. Optical and AFM microscopies, mass quadrupole spectrometry, Rutherford backscattering analysis and X-ray photoelectron spectroscopy were used to analyze the irradiated GO foils. Results demonstrated that the GO loses oxygen with the laser irradiation becoming richer in sp2-hybridized carbon content.

Study of activation cross sections of deuteron induced reactions on erbium in the 32–50 MeV energy range

Activation cross sections of the natEr(d,x)163,165,166,167,168,170Tm and natEr(d,x)171,161Er nuclear reactions have been measured in the 32–50MeV energy range, above 40MeV for the first time. The activation method with stacked foil irradiation technique and gamma-ray spectroscopy were used. The experimental cross sections were compared with the theoretical predictions in the TENDL-2015 library.

Physical investigations on the radiation damage of graphene oxide by IR pulsed laser

Graphene oxide foils were irradiated by Nd:YAG laser at the moderated intensities of the order of 108 W/cm2 in vacuum. Measurements of atomic emission during the laser irradiation were performed with ion collectors and mass spectrometry, demonstrating a strong emission of carbon, oxygen and hydrogen atoms. Further investigations of the irradiated graphene oxide foils were carried out on pristine and laser irradiated samples by using Rutherford backscattering spectrometry and X-ray photoelectron spectroscopy. Results indicate that graphene oxide losses oxygen and hydrogen during the irradiation, changing its carbon content and its chemical and physical properties.

Investigation of Ionic Transport Through Track-Etched Conical Nanopores of PET Membrane

The control of ionic transportation inside the multi asymmetric conical nanopores in polyethylene terephthalate (PET) membrane was investigated. The conical nanopores were prepared by chemical etching in irradiated PET foil using etchant (9 M NaOH) and stopping solution (1 M NaCl [Formula: see text] 1 M HCOOH). The behavior of ionic current was recorded under stepping voltage [Formula: see text]2[Formula: see text]V to [Formula: see text]2[Formula: see text]V at different molar concentrations of potassium halides (KCl, KBr and KI) under symmetric bathing condition in electrochemical cell. It is found that the presence of multiple ionic species and the occurrence of counterion condensation of charge regulated polyelectrolyte play an effective role in ionic current rectification (ICR). The electrical conductance of conical nanopores may be estimated by measuring the ionic current rectification properties of track-etched nanopores. The charge transport properties vary with molar concentration and pH of electrolyte. Moreover, ICR may be used as a voltage gating phenomena with wide technological applications.

Laser modification of graphene oxide layers

The effect of linearly polarized laser irradiation with various energy densities was successfully used for reduction of graphene oxide (GO). The ion beam analytical methods (RBS, ERDA) were used to follow the elemental composition which is expected as the consequence of GO reduction. The chemical composition analysis was accompanied by structural study showing changed functionalities in the irradiated GO foils using spectroscopy techniques including XPS, FTIR and Raman spectroscopy. The AFM was employed to identify the surface morphology and electric properties evolution were subsequently studied using standard two point method measurement. The used analytical methods report on reduction of irradiated graphene oxide on the surface and the decrease of surface resistivity as a growing function of the laser beam energy density.

Study of activation cross sections of deuteron induced reactions on barium. Production of 131Cs, 133Ba

Abstract In the frame of a systematic study of deuteron induced activation processes on middle mass elements, excitation functions of the nat Ba(d,x) 135,133,132 La, 135m,133m,133mg,131mg Ba, 136mg,134mg,132,129 Cs reactions were measured up to 50 MeV for the first time. Cross sections were measured with the activation method using a stacked foil irradiation technique followed by HPGe γ -ray spectrometry. A comparison with the results of the nuclear model TALYS code (reported in the TENDL-2015 library) was done. The potential use of the deuteron induced reactions on Ba for applications ( 131 Cs and 131 Ba production) is discussed.

Immuno-PET in Pontine Glioma: More Than Meets the Eye?

610 Objectives: The success of PET imaging with 68Ga-labeled somatostatin and PSMA ligands has created a markedly increased demand for 68Ga that is challenging to meet with existing 68Ge/68Ga generators. In addition, preparation of patient doses is relatively expensive, because only small batches of the ligands can be prepared that each need to undergo QC procedures. The objective of this study was therefore to investigate the cyclotron production of 68Ga from a solid 68Zn target and the feasibility of using cyclotron produced 68Ga for preparing 68Ga-PSMA-11. We also evaluated how a decrease of specific activity - as would occur during the shipment of larger batches of 68Ga-PSMA-11 - affects tumor and normal organ uptake of [asterisk]Ga-PSMA-11 in mouse models of prostate cancer. Methods: Enriched 68Zn foils were irradiated were irradiated with 11.5 MeV protons for 1-3 h at a beam current of 30-75 µA in a GET PETTRACE cyclotron. The irradiated foils were dissolved in 10 N HCl and the solution passed through a cation exchanging resin to trap 68Ga and 68Zn. 68Zn was then eluted from the column using HBr in 80% acetone. Finally, 68Ga was eluted with 3 N HCl and used to label 68Ga-PSMA-11. In order to study the impact of injected mass on tumor and normal organ of [asterisk]Ga-PSMA-11 we injected mice bearing PSMA expressing PC3-PIP or LNCaP tumors with 3.3 - 10000 pmol of total ligand (67Ga-PSMA-11 and PSMA-11) labeled with 100-200 µCi of (67Ga) and performed a biodistribution study 1 h post injection. We also injected tumor bearing with cyclotron produced and generator produced 68Ga-PSMA-11 and performed PET imaging studies 1h post injection. Results: Up to 4.2 Ci of 68Ga were produced from the 68Zn foil before purification and, 1.8 Ci after purification. The 67Ga content was less than 0.1%. Specific activity of the produced 68Ga-PSMA-11 was 2.2-7.0 mCi/µg and radiochemical purity > 99%. The 68Ga-PSMA-11 met all the usual criteria for PET radiopharmaceuticals (bubble, LAL, and sterility test). There was no significant change in tumor uptake of 67Ga-PSMA-11 up to an injected mass of 1000 pmol for PC3-PIP and LNCaP tumors (333-fold range). PET images of tumor bearing mice injected with 800 pmol of 68Ga-PSMA11 demonstrated identical biodistribution in normal organs and tumors. Conclusions: 68Ga can be produced in Ci amounts using a medical cyclotron. The cyclotron produced 68Ga product appears suitable for labeling PSMA11 for future clinical trials.The injected mass of PSMA-11 (on a per weight basis) had no significant impact on tumor uptake in mice up to a more than 300-fold higher mass than used for human PET/CT studies with 68Ga-PSMA11. This suggests that batches of cyclotron produced 68Ga-PSMA11 may be shipped for several hours after production.

Validation of a Monte Carlo HPGe detector model against irradiated foil gamma-ray spectroscopy measurements

A high-purity germanium detector Monte Carlo model was evaluated for its ability to predict activation product ratios in Fe, Cr, Ni, and stainless-steel foils. To evaluate the model, activation product ratios calculated from simulated gamma-ray spectra were compared against those from experiment measurements. Analysis shows that the detector model accurately predicts activation product ratios within 10% when free of interferences. Presence of a shield chamber greatly increases computation time, but does not provide any quantitative advantages. Overall, the model is useful for predicting activation product ratios and experiment planning.

Separation of lead and bismuth from proton irradiated lead–bismuth eutectic (LBE) target by differential precipitation

A thin foil of lead–bismuth eutectic (LBE) has been bombarded with 18 MeV proton beam. Production of 203,204,205,206Bi along with 203Pb was observed. This paper reports the separation of bulk Pb and Bi from LBE target based on their differential precipitation properties. The irradiated foil in HNO3 medium was evaporated to dryness and after addition of deionised water, Bi precipitated out while Pb remained in supernatant with 86,000.

Distribution of deuterium and hydrogen in Zr and Ti foil assemblies under the action of a pulsed deuterium high-temperature plasma

Deuteron and proton elastic recoil detection analysis is used to study the accumulation and redistribution of deuterium and hydrogen in assemblies of two high-pure zirconium or titanium foils upon pulsed action of high-temperature deuterium plasma (PHTDP) in a plasma-focus installation PF-4. It is noted that, under the action of PHTDP, an implanted deuterium and hydrogen gas impurity are redistributed in the irradiated foils in large depths, which are significantly larger than the deuterium ion free paths (at their maximum velocity to ~108 cm/s). The observed phenomenon is attributed to the carrying out of implanted deuterium and hydrogen under the action of powerful shock waves formed in the metallic foils under the action of PHTDP and/or the acceleration of diffusion of deuterium and hydrogen atoms under the action of a compression–rarefaction shock wave at the shock wave front with the redistribution of deuterium and hydrogen to large depths.

Measurement of activation cross-section of long-lived products in deuteron induced nuclear reactions on palladium in the 30–50 MeV energy range

Excitation functions were measured in the 31–49.2MeV energy range for the natPd(d,xn)111,110m,106m,105,104g,103Ag, natPd(d,x) 111m,109,101,100Pd, natPd(d,x), 105,102m,102g,101m,101g,100,99m,99gRh and natPd(d,x)103,97Ru nuclear reactions by using the stacked foil irradiation technique. The experimental results are compared with our previous results and with the theoretical predictions calculated with the ALICE-D, EMPIRE-D and TALYS (TENDL libraries) codes.

Optical imaging of irradiated cyclotron target window foils using Cerenkov and radioluminescence imaging

Radioisotopes production for PET radiopharmaceuticals is performed using cyclotrons resulting in radio activation of different cyclotron components. It is thus necessary to measure the level of radiation exposure and, if possible, to image the areas where most of the radiations are emitted in particular during maintenance or decommissioning procedures. In this work we present a novel optical imaging approach using Cerenkov luminescence imaging (CLI) and radioluminescence imaging (RLI). CLI was performed by placing a glass Cerenkov radiator on a target window (Havar foils) and RLI data were obtained by covering the Havar foils with an intensifying screen. CLI or RLI were acquired using a small animal optical imaging system used in bioluminescence mode without the use of any optical filters. The analysis of the normalized radiance line profiles of both CLI and RLI images showed a similar pattern, however the absolute radiance of the RLI signal is several order of magnitude higher with respect to CLI. We conclude that optical imaging with CLI and RLI can be considered a novel method to detect and image activation areas in irradiated samples from a medical cyclotron.

Study of deuterium and hydrogen distributions in Ta|CD2|Ta, Ta|Ta|CD2|Ta|Ta, and Nb|CD2|Nb assemblies after exposure to high-temperature argon plasma

Assemblies made of Ta|CD2|Ta, Ta|Ta|CD2|Ta|Ta and Nb|CD2|Nb foils are irradiated with pulses of high-temperature argon plasma created by means of a “Plasma Focus” setup. The irradiated foil samples are investigated by recording the recoil nuclei of hydrogen and deuterium. It is found that hydrogen and deuterium are redistributed in foil stacks. The ultradeep penetration of light gas impurities (hydrogen and deuterium) can be explained by the influence of shock waves on the foils and accelerated diffusion under an external force.

Extension of activation cross section data of long lived products in deuteron induced nuclear reactions on platinum up to 50 MeV

In the frame of a systematical study of light ion induced nuclear reactions on platinum, activation cross sections for deuteron induced reactions were investigated. Excitation functions were measured in the 20.8–49.2MeV energy range for the natPt(d,xn)191,192,193,194,195,196m2,196g,198g,199Au, natPt(d,x)188,189,191,195m,197m,197gPt and natPt(d,x)189,190,192,194m2Ir reactions by using the stacked foil irradiation technique. The experimental results are compared with previous results from the literature and with the theoretical predictions in the TENDL-2014 and TENDL-2015 libraries. The applicability of the produced radio-tracers for wear measurements has been presented.

Activation cross section data of proton induced nuclear reactions on lanthanum in the 34–65 MeV energy range and application for production of medical radionuclides

Activation cross sections of the natLa(p,x)139,137m,137g,135,134,133mCe, natLa(p,x)135,134,133La and 133m,133g,131Ba nuclear reactions have been measured experimentally, for the first time (except 139Ce). Cross-sections in the 34-64 MeV energy range were obtained through an activation method combining the stacked foil irradiation technique and gamma-ray spectrometry. The experimental cross sections were compared with the theoretical prediction in the TENDL-2014 and TENDL-2015, TALYS based libraries. Applications in the field of medical radionuclides production is discussed.

Study of the expansion dynamics of the plasma of a thin aluminum foil under the action of soft X-ray emission

Results are presented from experiments on the irradiation of thin aluminum foils by an intense soft X-ray (SXR) source on the basis of the Z-pinch formed during the implosion of a tungsten wire array at the Angara-5-1 facility. The state of the foil target is examined by taking two-dimensional X-ray frames. The expansion velocity of the plasma formed under the action of pulsed SXR emission on the front (irradiated) and back sides of the foil and the glow intensity of aluminum plasma on the back side are found from the spatial distribution of the radiation intensity of the plasma of the irradiated foil. The time at which the foil plasma becomes transparent to Z-pinch radiation is determined from the increase in the intensity of transmitted SXR emission.

Production of platinum radioisotopes at Brookhaven Linac Isotope Producer (BLIP)

The accelerator production of platinum isotopes was investigated at the Brookhaven Linac Isotope Producer (BLIP). In this study high purity natural platinum foils were irradiated at 53.2, 65.7, 105.2, 151.9, 162.9 and 173.3.MeV. The irradiated foils were digested in aqua regia and then converted to their hydrochloride salt with concentrated hydrochloric acid before analyzing by gamma spectrometry periodically for at least 10 days post end of bombardment. A wide range of platinum (Pt), gold (Au) and iridium (Ir) isotopes were identified. Effective cross sections at BLIP for Pt-188, Pt-189, Pt-191 and Pt-195m were compared to literature and theoretical cross sections determined using Empire-3.2. The majority of the effective cross sections (<70 MeV) confirm those reported in the literature. While the absolute values of the theoretical cross sections were up to a factor of 3 lower, Empire 3.2 modeled thresholds and maxima correlated well with experimental values. Preliminary evaluation into a rapid separation of Pt isotopes from high levels of Ir and Au isotopes proved to be a promising approach for large scale production. In conclusion, this study demonstrated that with the use of isotopically enriched target material accelerator production of selected platinum isotopes is feasible over a wide proton energy range.

Measurement of isomeric yield ratios for the 110Pd(γ,n)109m,gPd reaction

We measured the isomeric yield ratios for the 110Pd(γ,n)109m,gPd reaction by the activation method with the bremsstrahlung endpoint energies of 50-, 55-, 60-, 65-, and 70-MeV generated from an electron linear accelerator of Pohang accelerator laboratory. The induced γ-activities of the irradiated palladium foils were measured by a coaxial high purity germanium detector coupled to a PC-based multi-channel analyzer. The necessary corrections were made to improve the accuracy of the γ-activity measurements. The present experimental results measured with bremsstrahlung endpoint energies of 50-, 55-, 60-, 65-, and 70-MeV are 0.108 ± 0.007; 0.118 ± 0.008; 0.118 ± 0.007; 0.120 ± 0.008; 0.119 ± 0.008, respectively. The obtained results are compared with those existing in literature.