Ray Beam Research Articles

THREE-COMPONENT LENS ZOOM-AFOCAL SYSTEMS FOR TRANSFOCATORS

Background. Parametric synthesis of zoom-afocal optical systems for zoom lenses. Development of an algorithm for dimensional calculation of three-component zoom-afocal systems when accounting overall limitations, providing the desired range of changes in the angular magnification and field of view of the zoom lens, the allowable vignetting of the extreme beams of light when the field of view changes over the entire specified range. Synthesis of an afocal system for a stationary lens, the entrance pupil of which is located behind the afocal system.Objective. The purpose of the paper is to create a universal analytical and suitable for computer automation algorithm for calculation of the optical and overall parameters of the components of zoom-local three-component zoom systems.Methods. The zoom-afocal system is represented by subtle components. A system of equations is compiled in which the distances between the components are unknown. From the equations, the values of these distances are recovered, which provide the necessary values of the angular magnification and zero optical power of the afocal system. In this case, the magnitudes of the optical powers of the components and their ratios should ensure positive values of the distances between them. Using the formulae of the angles and heights of the zero rays on the components of the system, taking into account the permissible vignetting of the beam of rays from the edge of the field of view, the required light diameters of the components are determined.Results. The obtained analytical dependences allow us to determine the focal distances of the afocal system components and their mutual location over the entire required range of changes in the angular magnification using the original data on the allowable longitudinal and transverse dimensions of the afocal system. It is shown that afocal systems have a maximum axial length with the angular increase of one. The largest light diameter has the first component. The diameter of this component reaches its greatest value as the value of the angular increase is close to one.Conclusions. The obtained results allow analytically performing parametric synthesis of three-component zoom-afocal systems, taking into account the requirements for their dimensions, the range of changes in the angular magnification and permissible vignetting of beams of rays from the edge of the visual field.

Investigation of polymer-based BaO and rGO nanocomposites for application in low energy X ray attenuation

Polymeric materials can serve as a matrix for the dispersion of nanomaterials with good attenuation features, resulting in lightweight, conformable, flexible, lead-free and easy-to-process materials. Thus, some well-known radiation shielding materials could be used in low proportion as a filler, for the formation of new materials. On the other hand, nanostructured carbon materials, such as graphene oxide (GO) have been reported recently to show enhanced attenuation properties. For the present work, poly(vinylidene fluoride) [PVDF] homopolymers and its fluorinated copolymers were filled with metallic oxides and nanosized reduced graphene oxides (rGO) in order to produce nanocomposites with increased low energy X ray attenuation efficiency. We objective is to investigate the X ray shielding features of multilayered PVDF/rGO and P(VDF-TrFE)/BaO composites. PVDF/rGO overlapped with P(VDF-TrFE)/BaO thin films were sandwiched between two layers of kapton films of different thickness. The linear attenuation coefficients were measured for monochromatic X ray photons with energy of 8.1 keV. The samples were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Ultraviolet–visible (UV-vis) and Fourier-Transform Infrared (FTIR) Spectroscopy. The linear attenuation coefficient of the multilayered sample was evaluated and compared with the linear attenuation of the individual constituents. It was observed an increase in the attenuation coefficient of the overlapping samples. It is demonstrated that thin films of rGO nanocomposite with thickness of only 0.32 mm can attenuate up to 50% of X ray beams with energy of 8.1 keV, justifying further investigation of these nanocomposites as X ray or gamma radiation attenuators

Thermoluminescence characteristics and dose response of electron beam and gamma rays irradiated alumino-phosphate glasses doped with Gd2O3 and Tb2O3

Phosphate glass samples doped with Gd2O3 and Tb2O3 oxides were synthesized and studied towards potential application in high dose radiation measurements. Glass/polytetrafluoroethylene composite detectors were prepared and used to study dosimetric signal dependencies, and thermoluminescence dosimetry (TLD) technique was used as a main investigation tool to study detectors response. Influence of dopants and polymer on TL signal were investigated. The dosimetric properties, like dose response, linearity and signal stability of the composite dosimeters were investigated. Incorporation of lanthanide oxides into glass matrix changes substantially the thermoluminescent behavior of phosphate glass. The highest luminescence yield exhibits glass doped with terbium oxide. Negligible influence of polytetrafluoroethylene agglutinator on dosimetric signal was observed. Dependence of the integrated thermoluminescent signals for all samples vs. absorbed dose can be considered as linear. The new phosphate glass-polytetrafluoroethylene composites show good material and thermoluminescent properties for the high gamma and electron beam dose measurement applications.

Comparative effect of high energy electron beam and 137Cs gamma ray on survival, growth and chlorophyll content in curcuma hybrid ‘Laddawan’ and determine proper dose for mutations breeding

Curcuma alismatifolia is an ornamental plant with a beautiful flower in the curcuma genus, which is popular in Thailand and other countries. C. alismatifolia has been improved as the market needs. This research aimed to induce mutations and to study the effects of electron beam and gamma ray on tissue culture of the Curcuma hybrid ‘Laddawan.’ Eight-weeks-old plantlets were irradiated by gamma ray with a Mark I irradiator at the dose rate of 3.74 Gy/min, at the Nuclear Technology Research Center, Kasetsart University. For the electron beam irradiation, samples were exposed to a high-energy electron beam. The lowest power of this machine is 10 MeV and the lowest radiation dose per cycle is 50 Gy (240 Gy/min). The comparison between the effects of gamma ray and electron beam irradiation at doses of 0, 50, 100 and 200 Gy showed that survival percentage, growth percentage, and chlorophyll content were significantly decreased (P<0.05) when radiation dose increased. The survival percentage, growth percentage and chlorophyll content of gamma-irradiated samples were higher than the electron beam-irradiated samples in the same dose. The results indicated the optimum dose range for gamma irradiation of Curcuma hybrid ‘Laddawan’ in tissue culture is 30 – 60 Gy and for electron beams the dose should be less than 50 Gy. New characteristics (variegated leaves and light green leaves) were found in M1V2.

Radiation-Induced Breeding in Camelina Sativa

The ionizing radiation methods, including X-rays, gamma rays, and neutrons to create variation is well established and used in major crops. Many seed-propagated crops with homozygous parents such as barley, rice, and tomato are resilant to the higher level of damage to chromosomal DNA during mutation induction, followed by repair. In order to improve oil content and other agronomic traits, we treated Camelina sativa Crantz with diverse levels of gamma ray and neutron beam. Overall, 300 Gy of gamma ray and at 50 Gy of neutron beam treated C. sativa showed better agronomic traits. 400 Gy of gamma rays and 200 Gy of fast neutron treatments increased almost four times more oil content than non-treated seeds. In conclusion, our results provide a rapid and economical means to improve agronomic characters of camelina in breeding programs. This is undoubtedly highly valuable, pre-breeding material especially for high oil content.

γ -ray strength function for thallium isotopes relevant to the Pb205−Tl205 chronometry

Photoneutron cross sections were measured for $^{203}$Tl and $^{205}$Tl at energies between the one- and two-neutron thresholds using quasi-monochromatic $\gamma$-ray beams produced in laser Compton-scattering at the NewSUBARU synchrotron radiation facility. Our new measurement results in cross sections significantly different from the previously reported bremsstrahlung experiment, leading to rather different GDR parameters, in particular to lower GDR peak energies and higher peak cross sections. The photoneutron data are used to constrain the $\gamma$-ray strength function on the basis of the Hartree-Fock-Bogolyubov plus quasi-particle random phase approximation using the Gogny D1M interaction. Supplementing the experimentally constrained $\gamma$-ray strength function with the zero-limit E1 and M1 contributions for the de-excitation mode, we estimate the Maxwellian-averaged cross section for the s-process branching-point nucleus $^{204}$Tl in the context of the $^{205}$Pb - $^{205}$Tl chronometry.

Злокачественная трансформация мезенхимальных стволовых клеток из разных тканей мыши после смешанного гамма-нейтронного облучения in vitro

Purpose: To study the possibility of malignant transformation of control and irradiated mesenchymal stromal stem cells (MSC) from the bone marrow (BM) and brain (BR) and from the adipose tissue (AT) of mice and some cytokines secretion after mixed γ,neutron (γ, n) irradiation and γ-irradiation. Material and methods: MSCs were isolated and cultured according to generally accepted protocols. γ, n-irradiation was carried out by a collimated beam of neutrons and gamma rays at a special station of the nuclear reactor IR-8. MSCs were irradiated at the 29th passage at doses of 0.05; 0.5 and 2 Gy, were cultured for 10 passages and transplanted subcutaneously 1×106 cells to C57BL/6 syngeneic mice. MSCs AT were irradiated at the facility GUT-200M (60Co) at doses 1–6 Gy. The level of cytokines in the culture medium of MSC was measured by an ELISA. Results: A decrease in RBE was observed after radiation dose increasing from 0.5 to 4.0 Gy. The maximum of RBE for all MSCs, equal to 5.5, was observed at a dose of 0.5 Gy. After the dose increasing to 2 Gy an average RBE decreased to 2.5, and at dose 4.0 Gy RBE it was 2.0. Tumors were detected after 5 months after transplantation into syngeneic mice of MSC BM irradiated at doses of 0.05; 0.5 and 2 Gy. After transplantation of control MSCs BM and of control and irradiated MSCs BR and MSC AT, no tumors were detected. After subcutaneous injection of γ-irradiated at doses of 0.1; 1 and 6 Gy MSC AT, unlike MSCs BM, no tumors were detected. Histological examination of tumors revealed signs of a low-grade fibrosarcoma with active proliferation and a high degree of malignancy. Tumors contained inclusions from the derivatives of several tissues of mesenchymal origin – muscular, fatty, cartilaginous and bone. In the case of a tumor that developed after transplantation of MSCs BM exposed to γ,n-radiation at a dose of 0.05 Gy, the contact metastasis was detected in the shoulder with the penetration of tumor cells between the muscle fibers. From the tumors, the mouse fibrosarcoma cell lines were obtained. The highest level of cytokines VEGF, HGF and IL6was found in the culture medium of MSC AT. The level of TGFβ secretion was practically the same in all studied MSCs. After γ,n-irradiation an increase of VEGF secretion in MSC BM, a decrease of IL6 secretion in MSC BM and MSC BR, and an increase in its secretion in MSC AT were detected. Conclusions: The obtained results testify the high sensitivity of MSC BM to malignant transformation after ionizing irradiation and the much higher resistance of mouse MSC BR and MSC AT. The mechanisms of these differences are yet not known. The highest level of cytokines VEGF, HGF and IL6 was found in the culture medium of MSC AT. After the action of γ,n-radiation, as well as after the action of γ-radiation, the secretion profile of the investigated cytokines was changed, depending both on the dose and on the type of radiation.

Biological Effects of Seed Irradiation by Synchrotron X Ray Beam in Young Bean Seedlings

Irradiated seeds of Phaseolus vulgaris cv. Rajmah using Synchrotron X Ray Beam (BL-07) in RRCAT, Indore at doses of 1, 10 and 20 Gy were used to raise the seedling and the effects on growth and biochemical constituents in 4 - 8 days, old seedlings were analyzed. The seed irradiation effect on seedling development up to about 4 - 5 days, % germination, seedling length and seedling vigor are significantly decreased at 10 and 20 Gy doses with strong -ve correlation. Other parameters, like relative water content, electrical conductivity and acid phosphatase activity are also decreased. Decrease in various biochemical constituents, like, protein and proline has shown significant reduction at 10 and 20 Gy and phenol at 1 - 20 Gy. However, peroxidase activity is increased at 1 and 10 Gy. Amongst the antioxidant enzymes, only superoxide dismutase activity has shown significant increase at 10 and 20 Gy. For seed irradiation (1 and 10 Gy) effect on seedling development up to 8 days involving transfer to hydroponic culture after 4 days, in shoot tissue, decrease in nitrate reductase activity and pigment content is observed, while nitrate reductase activity in root tissue is increased. The results demonstrate adverse effects on growth as well as biochemical constituents along with increased antioxidant effect in bean seedlings with irradiation of seeds at high dose of synchrotron X radiations. Also the nitrate assimilation and photosynthetic activity are reduced in shoot tissue with seed irradiation, however, increased nitrate reductase activity in roots suggests the involvement of NO signaling.

Radiation effect on germination and seedling traits in rice (Oryza sativa L.)

The biological effect of new source of physical mutagen viz., electron beam over gamma rays were studied with different dosages in the M1 generation of rice during 2017-18. The seeds of rice variety Anna (R) 4 rice were treated with 100 to 400 Gy of electron beam and gamma rays. At higher dosage level of 400 Gy both in gamma rays and electron beam, the germination percentage was reduced to 28 and 24 per cent respectively. The LD50 value was fixed as 273.27 Gy for electron beam, which is much lower dose than gamma rays (376.57Gy). During germination, root length was more affected than shoot length in both radiations. The electron beam irradiation affected maximum reduction in pollen fertility (61.87%) and in spikelet fertility (72.75%) at 400 Gy, whereas at same dose lesser reduction was observed in gamma rays. The relationship between pollen and spikelet fertility showed positive significant. The above information obtained from this study is more useful to understand the effect of electron beam on rice over gamma rays and also help to decide the dose for future mutation breeding programme in rice.

High power gamma flare generation in multi-petawatt laser interaction with tailored targets

Using quantum electrodynamics particle-in-cell simulations, we optimize the gamma flare (γ-flare) generation scheme from the interaction of a high power petawatt-class laser pulse with a tailored cryogenic hydrogen target having an extended preplasma corona. We show that it is possible to generate an energetic flare of photons with energies in the GeV range and the total flare energy being on a kilojoule level with efficient conversion of the laser pulse energy to γ-photons. We discuss how the target engineering and the laser pulse parameters influence the γ-flare generation efficiency. This type of experimental setup for a laser-based γ-source would be feasible for the upcoming high-power laser facilities. Applications of high intensity γ-ray beams are also discussed.

Measurement of the Se80(γ,n) reaction with linearly polarized γ rays

This paper reports the results of the first measurements of the differential cross section of the $^{80}\mathrm{Se}(\ensuremath{\gamma},n)^{79}\mathrm{Se}$ reaction with a linearly polarized gamma-ray ($\ensuremath{\gamma}$-ray) beam. The cross section was measured at three incident $\ensuremath{\gamma}$-ray beam energies: 15.6, 15.8, and 16.0 MeV, with a beam energy spread of 3.0% full width at half-maximum (FWHM). The differential cross section for the excitation spectrum in $^{79}\mathrm{Se}$ was measured at two scattering angles in the plane of the beam polarization: $\ensuremath{\theta}={90}^{\ensuremath{\circ}}$ and ${135}^{\ensuremath{\circ}}$, and at one angle in the plane perpendicular to the plane of polarization: $\ensuremath{\theta}={90}^{\ensuremath{\circ}}$. The total photoneutron cross sections determined from these data are between 0.8 and 1.3 standard deviations smaller than previously published results. The excitation spectra measured in this work were fit with a Hauser-Feshbach model. Better fits to the data were obtained with a constant-temperature formulation of the nuclear level density (NLD) than with a Fermi-gas NLD model. The parameters for the constant-temperature NLD model obtained in this work are consistent with those obtained for medium-mass nuclei in previous studies.

Photoneutron cross sections for Ni isotopes: Toward understanding (n,γ) cross sections relevant to weak s -process nucleosynthesis

Photoneutron cross sections were measured for $^{58}$Ni, $^{60}$Ni, $^{61}$Ni, and $^{64}$Ni at energies between the one-neutron and two-neutron thresholds using quasi-monochromatic $\gamma$-ray beams produced in laser Compton-scattering at the NewSUBARU synchrotron radiation facility. The new photoneutron data are used to extract the $\gamma$-ray strength function above the neutron threshold complementing the information obtained by the Oslo method below the threshold. We discuss radiative neutron capture cross sections and the Maxwellian-averaged cross sections for Ni isotopes including $^{63}$Ni, a branching point nucleus along the weak s-process path. The cross sections are calculated with the experimentally constrained $\gamma$-ray strength functions from the Hartree-Fock-Bogolyubov plus quasi-particle-random phase approximation based on the Gogny D1M interaction for both $E1$ and $M1$ components and supplemented with the $M1$ upbend.

Near-barrier photofission in Th232 and U238

A study of photofission of $^{232}\mathrm{Th}$ and $^{238}\mathrm{U}$ was performed by using quasimonoenergetic, linearly polarized $\ensuremath{\gamma}$-ray beams from the High Intensity $\ensuremath{\gamma}$-ray Source at Triangle Universities Nuclear Laboratory. The prompt-photofission neutron polarization asymmetries, neutron multiplicities, and the photofission cross sections were measured in the near-barrier energy range of 4.3 to 6.0 MeV. This data set constitutes the lowest energy measurements of those observables to date using quasimonoenergetic photons. Large polarization asymmetries are observed in both nuclei, consistent with the $E1$ excitation as observed by another measurement of this kind made in a higher-energy range. Previous experimental evidence of a deep third minimum in the $^{238}\mathrm{U}$ fission barrier has been identified as an accelerator-induced background.

HARPO, a gas TPC active target for high-performance γ-ray astronomy; demonstration of the polarimetry of MeV γ-rays converting to e+e− pair

No $\gamma$-ray polarimeter sensitive above 1 MeV has ever flown space. $\gamma$-ray polarimetry would be a new window on the radiative processes at work in cosmic sources, processes that produce linearly polarised emission, each of which with different polarisation fractions. The HARPO Collaboration has designed, built and characterised on beam a gas-TPC active target with which we have demonstrated for the first time the polarimetry of a linearly polarised MeV $\gamma$-ray beam, from the analysis of the conversions to $e^+ e^-$ pairs.

Use of Gamma Ray Back Scattering Method for Corrosion Assessment in Insulated Pipes

Corrosion of insulated pipes is a major problem in nuclear,petrochemical and other industries.This type of corrosion is difficult to measure by the available techniques of ultrasound and transmission gamma or x-ray radiography due to the presence of insulating material and limited accessibility to both sides. Gamma-ray backscattering technique is a non-contactmethod and is highly suitable for buried insulated pipes where access is limited to one side only.In the present work, MCNP5 code was used to simulate a case where pipe corrosion (i.e., wall thinning) was measured by gamma backscattered technique. A steel pipe is bombarded by collimated gamma ray beam of 1 cm diameter from an 8 mCi137Cs source. The pipehad different wall thicknesses and was wrapped with a commercially available insulator. Upon interaction with the pipe wall, a 2x2 cm NaI (Tl) scintillation detector was used to measure the scattered radiation due to Compton scattering. The codewas used to evaluate the sensitivity of the device to predict pipe wall thinning as an indication for pipe corrosion. Then, parametric analysis was done to investigate the effects of pipe diameter, insulator thickness, source collimator diameter, source shield thickness as well as the thickness of the shied between the source and the detector on the device response. Effect of empty vs. water-filled pipes on the device response was also investigated. Results indicate that Gamma-ray backscattering technique can be used successfully as a non-destructive test for measuring wall thinning of insulated pipes as an indication of their corrosion.

Study of dosimetric properties of flattened and unflattened megavoltage x ray beam on high Z implant materials.

PurposeAddition of high Z implants in the treatment vicinity or beam path is unavoidable in certain clinical situation. In this work, we study the properties of radiation interaction parameters such as mass attenuation coefficient (MAC), x ray beam transmission factor (indirect beam attenuation), interface effects like backscatter dose perturbation factor (BSDF) and forward dose perturbation factor (FDPF) for flattened (FF) and unflattened (UF) x ray beams.Methods MAC for stainless steel and titanium alloy was measured using CC13 chamber with appropriate buildup in narrow beam geometry. The x ray beam transmission factors were measured for stainless steel and titanium alloy for different field size, off‐axis, and depths. Profile analysis was performed using a radiation field analyzer (RFA) as a function of field size and depth to study the influence of phantom scattering and spectral variation in the beam. In addition, interface effects such as BSDF and FDPF were measured with gafchromic films at maximum BSDF peak position calculated using Acuros XB algorithm and with PPC40 chamber measured at exit side of high Z material, respectively.ResultsThe MAC in both cases decreases with increase in energy for stainless steel (SS) and titanium (Ti) alloy. The MAC increases with the change in x ray beam type from flattened to UF beam because of relatively lower mean energy. The x ray beam transmission factor increases with the increase in energy, field size, and depth owing to increase in penetration power phantom scatter, respectively. The measured BSDF and FDPF were found to be in good agreement with AXB algorithm.ConclusionThe dosimetric properties of x ray photon beam were studied comprehensively in the presence of high Z material like stainless steel and titanium alloy using both flattened and UF beams to understand and incorporate the findings of various parameters in clinical condition due to the variation in energy spectrum from FF to UF x ray beam.

Investigation ofJ=1states and theirγ-decay behavior inCr52

Background: In the $A\ensuremath{\approx}50$ mass region $M1$ spin-flip transitions are prominent around 9 MeV. An accumulation of ${1}^{\ensuremath{-}}$ states between 5 and 8 MeV generating additional $E1$ strength, also denoted as pygmy dipole resonance, has been established in many nuclei with neutron excess within the last decade.Purpose: The $\ensuremath{\gamma}$-decay behavior of $J=1$ states has been investigated in an NRF experiment. $M1$ excitations have been compared to shell model calculations.Methods: $J=1$ states were excited by quasi-monoenergetic, linearly polarized $\ensuremath{\gamma}$-ray beams generated by laser-Compton backscattering at the $\mathrm{HI}\ensuremath{\gamma}\mathrm{S}$ facility, Durham, NC, USA. Depopulating $\ensuremath{\gamma}$ rays were detected with the multidetector array ${\ensuremath{\gamma}}^{3}$.Results: For eleven beam-energy settings the $\ensuremath{\gamma}$-decay behavior of dipole states was analyzed by a state-to-state analysis and average $\ensuremath{\gamma}$-decay branching ratios have been investigated. 34 parity quantum numbers were assigned to $J=1$ states.Conclusions: Six ${1}^{\ensuremath{-}}$ states and two ${1}^{+}$ states have been investigated in NRF experiments for the first time. The $M1$ strength distribution is in good agreement with shell-model calculations.

On spatial structure of the wave field in a vertical section of a deep water acoustic waveguide

The spatial structure of the wave field excited by a tonal point source in an underwater acoustic waveguide with random sound speed fluctuations is analyzed. This is done using an approach in which the field is approximated by a sum of components formed by contributions of narrow beams of rays. These components fluctuate less than the total field and, therefore, they are called stable. Each ot them can be isolated from the total field recorded by a long vertical antenna, using the coherent state expansion developed in quantum mechanics. An approximate analytical expression is obtained for the correlation matrix of the superposition of several stable components. The applicability of this equation is confirmed by the results of Monte Carlo simulation. The simulation has confirmed the theoretical prediction that nearly the same stable components can correspond to the sound speed fluctuations with completely different correlation functions.

γ-Ray Beams with Large Orbital Angular Momentum via Nonlinear Compton Scattering with Radiation Reaction.

Gamma-ray beams with a large angular momentum may affect astrophysical phenomena, which calls for appropriate earth-based experimental investigations. For this purpose, we investigate the generation of well-collimated γ-ray beams with a very large orbital angular momentum using nonlinear Compton scattering of a strong laser pulse of twisted photons at ultrarelativistic electrons. Angular momentum conservation among absorbed laser photons, quantum radiation, and electrons is numerically demonstrated in the quantum radiation-dominated regime. We point out that the angular momentum of the absorbed laser photons is not solely transferred to the emitted γ photons, but due to radiation reaction shared between the γ photons and interacting electrons. The efficiency of the angular momentum transfer is optimized with respect to the laser and electron beam parameters. The accompanying process of electron-positron pair production is furthermore shown to enhance the orbital angular momentum gained by the γ-ray beam.

Evaluation of capsaicinoid profile and antioxidant properties in dried Korean red pepper (Capsicum annuum L.) as affected by variable dose rates of electron beam and gamma ray irradiation.

The application of food irradiation is based on the parameters including energy (MeV), dose rate (kGy/s or kGy/h), and absorbed dose (kGy). Red pepper powders were treated with different dose rates of 1, and 5kGy/s electron beam (EB) as well as 1.8 and 9kGy/h gamma ray (GR) in separate experiments. Constant absorbed dose (3kGy) was maintained to observe whether different dose rates affect the product quality. Total and individual capsaicinoids increased at low EB and GR dose rates. Vitamin C content decreased at all dose rates, except at low GR dose rate, where no significant difference was observed. Low EB dose rate led to a marked increase (21%) in the total phenolics than high dose rate (13%). In contrast, high GR dose rate increased the total phenolics than low dose rate. Maximum antioxidants (1.36mg TE/mL) were observed at high EB dose rate, although low dose rate also increased the antioxidant activity. Results indicated that different dose rates delivering the same absorbed dose had significant impact on the product quality and that the efficacy of absorbed dose is dependent on applied dose rates. In other words, a constant absorbed dose applied to the product is influenced by dose rate of the irradiation treatment.