Radiation-induced Reactions Research Articles

Understanding the Molecular Kinetics and Chemical Equilibrium Phase of Frozen CO during Bombardment by Cosmic Rays by Employing the PROCODA Code

Within the cold regions of space, ices that are enriched with carbon monoxide (CO) molecules are exposed to ionizing radiation, which triggers new reactions and desorption processes. Laboratory studies on astrochemical ices employing different projectiles have revealed the appearance of several new species. In this study, we employed the upgraded PROCODA code, which involves a calculation phase utilizing thermochemistry data, to map the chemical evolution of pure CO ice irradiated by cosmic-ray analogs. In the model, we have considered 18 different chemical species (six observed: CO, CO2, C3, O3, C2O, and C5O3; 12 unobserved: C, O, C2, O2, CO3, C3O, C4O, C5O, C2O2, C2O3, C3O2, and C4O2) coupled at 156 reaction routes. Our best-fit model provides effective reaction rates (effective rate constants, (ERCs)), branching ratios for reactions within reaction groups, several desorption parameters, and the characterization of molecular abundances at the chemical equilibrium (CE) phase. The most abundant species within the ice at the CE phase were atomic oxygen (68.2%) and atomic carbon (18.2%), followed by CO (11.8%) and CO2 (1.6%). The averaged modeled desorption yield and rate were 1.3e5 molecules ion−1 and 7.4e13 molecules s−1, respectively, while the average value of ERCs in the radiation-induced dissociation reactions was 2.4e-1 s−1 and for the bimolecular reactions it was 4.4e-24 cm3 molecule−1 s−1. We believe that the current kinetics study can be used in future astrochemical models to better understand the chemical evolution of embedded species within astrophysical ices under the presence of an ionizing radiation field.

Reaction mechanisms of Sn-complex-side-chain polymer used for extreme ultraviolet lithography, studied by electron pulse radiolysis and γ-radiolysis

The development of highly sensitive resists containing tin, which has a large EUV absorption cross section, has recently attracted considerable attention in EUV lithography. The effective utilization of secondary electrons is required for the development of high-performance resists. It is important to design resist materials on the basis of the mechanism of radiation chemical reactions. In this study, the radiation-induced reactions of tetraphenyltin (TPSn), triphenylsulfonium triflate (TPS-Tf), and the copolymer of triphenyl(4-vinylphenyl) stannane (TPSnSt) and 4-methacryloxyphenyldiphenylsulfonium triflate (MAPDPS-Tf) were investigated by electron pulse radiolysis and γ-radiolysis in controlled reaction systems. The decomposed products were analyzed by high-performance liquid chromatography. The G values of decomposed products were determined. For the copolymer, the holes generated by ionizing radiations moved to Sn units and electrons moved to TPS-Tf units. The tin complex side chain decomposed, producing benzene after hole transfer.

Concise review of non-invasive physical plasma as a promising treatment option for radiation injuries of the skin.

Radiation injury has a complex pathophysiology and can result in long-term impediment of the dermal barrier function. Historically, its treatment has been no different to that of thermal burns and it is not always possible to prevent an unpredictable and uncontrolled extension of the radiation-induced reactions. Non-invasive physical plasma (NIPP), a highly energised gas encompassing a combination of various reactive species, positively affects the key players involved in wound healing and proves to be a promising treatment option for chronic wounds and inflammatory skin disorders. Recent clinical evidence also suggests preliminary efficacy in radiation injury following therapeutic irradiation as a part of cancer therapy. Further research is warranted to also investigate the clinical value of NIPP in the context of unplanned or accidental radiation exposure, either as a topical treatment or possibly as an intraoperative procedure, to potentially improve the dermatological outcome and reduce symptoms in radiation victims.

Numerical modeling of radiation-induced reactions: Fricke dosimeter at 298 K, 198 K, and 77 K

The Fricke dosimeter is a widely used gamma radiation dosimetry system. The system is based on the detection of Fe2+ to Fe3+ oxidation in an aqueous solution of ferrous sulfate in sulfuric acid, exposed to ionizing radiation in the presence of oxygen. The system is formed by a series of highly dependent chemical reactions. We developed a numerical model of coupled differential equations based on the mass balance; each equation incorporates information about the formation and breakdown of each molecule, as well as a term that represents an external source of radiation. The numerical model can reproduce the behavior of the experimental data at room temperature. We proposed a correction factor to simulate the behavior of the dosimeter at temperatures of 198 K and 77 K, respectively, when the system is in a thermal bath of dry ice or liquid nitrogen. This model could support a variety of experimental challenges for radiation at low temperatures in different fields of industry and could have relevance for astrobiology problems by offering the possibility of simulating reactions in comets and other exoplanetary bodies.

An integrated ion trap for the photon-ion spectrometer at PETRA III.

We have added a multipole ion trap to the existing photon-ion spectrometer at PETRA III (PIPE). Its hybrid structure combines a ring-electrode trap with a segmented 16-pole trap. The interaction of gases and ions with extreme ultraviolet radiation from the beamline P04 is planned to be investigated with the newly installed multipole trap. The research focus lies on radiation-induced chemical reactions that take place in the interstellar medium or in the atmospheres of planets, including natural as well as man-made processes that are important in the Earth's atmosphere. In order to determine the mass-to-charge ratio of the stored ions as efficiently as possible, we are using an ion time-of-flight spectrometer. With this technique, all stored ions can be detected simultaneously. To demonstrate the possibilities of the trap setup, two experiments have been carried out: The photoionization of xenon and the ion-impact ionization of norbornadiene. This type of ion-impact ionization can, in principle, also take place in planetary atmospheres. In addition to ionization by photon or ion impact, chemical reactions of the trapped ions with neutral atoms or molecules in the gas phase have been observed. The operation of the trap enables us to simulate conditions similar to those in the ionosphere.

Predictors of radiation-induced skin reactions in patients with T-cell skin lymphomas after total skin irradiation: retrospective cohort study

INTRODUCTION: Skin reactions negatively affect a patient’s quality of life and may require radiation therapy premature interruption, what impairs illness control. Numerous agents determine tissue radiosensitivity, but demographic and lifestyle factors remain poorly understood. Those kind of patients herapeutic algorithm demands studies.OBJECTIVE: Radiation-induced skin reactions (RISR) formation and severity prognostic factors determination for primary malignant skin lymphomas patients.MATERIALS AND METHODS: 45 patients malignant T-cell skin lymphoma study, aged 38 to 82 years (29 mycosis fungoides patients, 2 lymphomatoid papulosis, 14 patients with primary anaplastic large cell skin lymphoma) received fast electrons total skin irradiation on the basis of the Federal State Institution «Russian Radiology and Surgical Technologies Scientific Center named after Academician A.M.Granov» of the Ministry of Health of the Russian Federation from 2012 to June 2022. Radiation therapy performed in the usual fractionation mode on linear electron accelerators Elekta Precise with 4–6 MeV bremsstrahlung total doses from 14 to 30 Gy (22±2.4 Gy). In order to identify the role of possible prognostic factors of skin toxicity — gender, age, body mass index (BMI), smoking status, lymphoma body surface area (BSA), the presence of concomitant diseases (diabetes mellitus and arterial hypertension) and previous chemotherapy.Statistics: Statistical analysis was performed using the IBM SPSS Statistics v. 26 program (developed by IBM Corporation). The value of p<0.05 was considered statistically significant. Verification of the sample belonging to the normal general population was carried out using the Shapiro–Wilk criterion. Spearman's rank correlation coefficient was used for correlation analysis. The regression parameters were estimated using the least squares method.RESULTS: The analysis revealed positive associations between the severity of RISR and predictor factors: BMI (r=0.799, p<0.01), smoking status (r=0.655, p<0.01), age (r=0.534, p<0.05), presence of diabetes mellitus (r=0.456, p<0.05), arterial hypertension (r=0.227, p<0.05), previous chemotherapy (r=0.422, p<0.01) and lymphoma body surface area (r=0.378, p<0.01). Severity of RISR scale value increase by those parameters. Negative links found between the severity of RISR and the total focal dose (SOD) of the beginning of their formation (r=–0.109, p<0.05).CONCLUSION: Formation and severity prognostic factors for the RCC upon fast electrons total skin exposure for patients with primary malignant T-cell skin lymphomas (mycosis fungoides, lymphomatoid papulosis, primary anaplastic large cell lymphoma of the skin) were identified.

Radiation-induced reactions in comet analogues

AbstractComets are a source of prebiotic molecules that likely enriched the early Earth during the Late Heavy Bombardment period. Laboratory experiments that replicate cometary conditions may facilitate understanding of the chemical reactions and supplement observational studies of these icy bodies. Prebiotic compounds, such as formic acid and formaldehyde, have been observed in comets. Furthermore, these compounds can easily be formed in experimental models using a variety of gas combinations and energy sources. We conducted experimental cometary simulations using radiation chemistry tools to obtain insight into the possible fate of formic acid and formaldehyde. The main results suggest a redundant system, signifying that the irradiation of formic acid forms formaldehyde molecules and vice versa. This phenomenon ensures the permanence of prebiotic molecules in high-radiation environments. Additionally, the potential role of forsterite and graphite was explored in cometary simulations. Our experimental results show the differential formation of aldehydes and other carbonyl-containing compounds dependent on the mineral phase present.

Radio-fluorogenic nanoclay gel dosimeters with reduced linear energy transfer dependence for carbon-ion beam radiotherapy.

The precise assessment of the dose distribution of high linear energy transfer (LET) radiation remains a challenge, because the signal of most dosimeters will be saturated due to the high ionization density. Such measurements are particularly important for heavy-ion beam cancer therapy. On this basis, the present work examined the high LET effect associated with three-dimensional gel dosimetry based on radiation-induced chemical reactions. The purpose of this study was to create an ion beam radio-fluorogenic gel dosimeter with a reduced effect of LET. Nanoclay radio-fluorogenic gel (NC-RFG) dosimeters were prepared, typically containing 100μM dihydrorhodamine 123 (DHR123) and 2.0wt% nanoclay together with catalytic additives promoting Fenton or Fenton-like reactions. The radiological properties of NC-RFG dosimeters having different compositions in response to a carbon-ion beam were investigated using a fluorescence gel scanner. An NC-RFG dosimeter capable of generating a fluorescence intensity distribution reflecting the carbon-ion beam dose profile was obtained. It was clarified that the reduction of the unfavorable LET dependence results from an acceleration of the reactions between DHR123 and H2 O2 , which is a molecular radiolysis product. The effects of varying the preparation conditions on the radiological properties of these gels were also examined. The optimum H2 O2 catalyst was determined to include 1mM Fe3+ ions, and the addition of 100mM pyridine was also found to increase the sensitivity. This technique allows the first-ever evaluation of the depth-dose profile of a carbon-ion beam at typical therapeutic levels of several Gy without LET effect.

Mepitel Film for the prevention of acute radiation dermatitis in breast cancer: A randomized multi-centre open-label phase 3 trial

390226 Background: Radiation dermatitis (RD) is common in patients undergoing breast radiation treatment (RT), with worse RD in patients with large breasts and after mastectomy. Mepitel Film (MF), a silicone-based polyurethane film with Safetac technology, may reduce RD. We hypothesized that MF might play a role in preventing RD in this group of patients at risk. Methods: Patients were randomly assigned to receive MF or standard skin care (2:1 ratio). Patients with large breasts after lumpectomy (bra size ≥ 36 inches or cup size ≥ C) or after mastectomy were eligible. Stratification factors included surgery type (lumpectomy vs. mastectomy), dose fractionation (conventional vs. hypofractionated), and administration of boost/bolus. The primary endpoint was grade (G) 2 or 3 RD using the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 during RT and within 3 months of completion of RT. Secondary endpoints included CTCAE G3, incidence of moist desquamation, use of topical antibiotic cream, and patient- (PROs) and clinician- (CRO) reported outcomes using the modified Radiation-Induced Skin Reaction Assessment Scale (RISRAS) and Skin Symptom Assessment (SSA). This study is registered with ClinicalTrials.gov (NCT04166799). Results: Between January 2020 and May 2022, 266 patients (66%) were randomly assigned to MF and 137 (34%) to standard care. After removing withdrawn patients, 376 patients were included in the modified intention-to-treat analysis. The incidence of G2 or 3 RD was significantly lower in MF patients compared to standard care (n = 39/251, 15.5%; 95% CI, 11.3-20.6% vs. n = 57/125, 45.6%; 95% CI, 36.7-54.8% respectively, odds ratio [OR]: 0.20, P < .0001). Benefits of MF over standard care remained significant in patients who developed G3 RD (n = 7, 2.8%; 95% CI, 1.1-5.7% vs. n = 17, 13.6%; 95% CI, 8.1-20.9%, OR: 0.19) and moist desquamation (n = 20, 8.0%; 95% CI, 4.9-12.0% vs. n = 24, 19.2%; 95% CI, 12.7-27.1%, OR: 0.36). When evaluating the combined patient and health care professional score using the RISRAS, the MF arm had significantly lower scores than standard care ( P < .0001); individual items on the RISRAS also favored MF for PROs (tenderness, discomfort of pain and burning sensation) and CROs (erythema and moist desquamation). Similarly, when assessed by the SSA, blistering/peeling, erythema, pigmentation, and edema in PROs, and pain/soreness, blistering/peeling, erythema, and pigmentation in CROs were significantly reduced in MF. Topical antibiotics were prescribed significantly less frequently in MF (23.1% vs. 43.2%, P < .0001). Three patients removed the film prematurely due to development of an allergic rash (n = 2) and excessive pruritis (n = 1). Conclusions: MF significantly reduces RD in breast cancer patients undergoing RT when compared to the standard care. We recommend changes to the clinical practice for RD prevention and inclusion of MF in high-risk patients in future guideline recommendations. Clinical trial information: NCT04166799.

Application and clinical efficacy of Sufu medical chitosan hydrogel dressing in radiation skin damage caused by radiotherapy for cervical cancer.

To investigate the benefits of Sufu medical chitosan hydrogel dressing(Sufu) in the prevention and control of radiation skin damage during radiotherapy for cervical cancer as a combined modality. Ninety-seven cervical cancer patients who underwent radiotherapy at the Cancer Hospital of China Medical University between May 2017 and November 2018 were recruited according to given inclusion and exclusion criteria. The patients were assigned to a control group (n=48, washing the perineal area with normal saline) and an observation group (n=49, application of Sufu onto the site of radiotherapy in addition to washing the perineal area with normal saline). The treatment regimens for the two groups continued until the end of radiotherapy. A comparison of the RTOG (Radiation Therapy Oncology Group) grading of acute radiation-induced skin reactions (ARISRs), pain intensity (measured by the verbal rating scale (VRS)) and post-treatment wound healing was drawn between the two groups. In the observation group, 81.6% (40/49) of the patients had radiation dermatitis, which was significantly lower than the incidence rate (95.8%, 46/48) in the control group (P <0.05). The observation group was at higher risk of radiation dermatitis when given a high radiation dose, while the control group was more likely to have radiation dermatitis when administered with a moderate radiation dose (P <0.05). The median time of occurrence of pain and the median time of onset of skin reactions were significantly later in the observation group as compared with the control group (P <0.05, respectively). In the observation group, the pain relief rate was 92.50% at Day-3, and the wound healing rate was 95.0% at Day-7, significantly higher than in the control group (73.9% and 80.4%) (P <0.05, respectively). During radiotherapy for cervical cancer, Sufu can effectively prevent and control radiation-induced skin and mucous membrane damage, delay the onset of radiation dermatitis and substantially reduce the incidence rate, relieve radiation dermatitis and pain and promote wound healing.

Effects of Cycloaminomethyl Derivatives of Sterically Hindered Dihydroxybenzenes on Radiation-Induced Reactions Involving Peroxyl and Alkyl Radicals

Effects of Cycloaminomethyl Derivatives of Sterically Hindered Dihydroxybenzenes on Radiation-Induced Reactions Involving Peroxyl and Alkyl Radicals

Reduction in severity of radiation-induced dermatitis in head and neck cancer patients treated with topical aloe vera gel: A randomized multicenter double-blind placebo-controlled trial.

To assess the efficacy of topical aloe vera gel on radiation induced dermatitis (RID) in head and neck cancer (HNC) patients. In this multicenter randomized double-blind controlled study, HNC patients treated with concurrent chemoradiation (CCRT) received either aloe vera gel or placebo gel. Adverse skin toxicity levels were evaluated with the radiation-induced skin reaction assessment scale (RISRAS). One hundred-twenty patients were enrolled in this study. Analysis of the baseline characteristics did not reveal any differences between the groups. The median RISRAS values from the 1st to the 8th week of the CCRT course were not statistically different between the two groups. In the 5th and 6th weeks of treatment, moderate to severe grades of skin erythematous were observed at values of 13.6% and 24.1% versus 27.8 and 42.6% for members of the aloe vera gel group and the placebo group, respectively (p=0.05 for the 5th week and p=0.038 for the 6th week). In the 7th week, moderate to severe instances of moist desquamation were observed in eight patients (19.0%) in the placebo group (p=0.001). Subjects experienced a burning sensation with RISRAS scores of 3-4 in the 7th week representing only 11.9% of patients in the placebo group (p=0.016). Topical applications of aloe vera gel significantly reduced moderate to severe grades of skin erythematous and instances of moist desquamation in HNC patients receiving CCRT. In this study, there was no prophylactic efficacy for RID in the aloe vera gel group when compared to the placebo group.

Sensitization mechanism of metal oxide nanocluster resists with carboxylic acid ligands

Metal oxide nanocluster resists are a promising candidate for enabling the high-volume production of semiconductor devices with high-numerical-aperture extreme ultraviolet exposure tools. In this study, the sensitization mechanism of metal oxide nanocluster resists was investigated by focusing on the radiation-induced reactions of carboxylic acid ligands. Radiolytic products in various solutions of unsaturated carboxylic acids, aromatic carboxylic acids, and saturated carboxylic acids were analyzed by electrospray ionization mass spectrometry, high-performance liquid chromatography, and dynamic light scattering. The conditions of the solutions were selected to control reaction paths of intermediates. The major reaction paths induced by ionizing radiation were clarified. The obtained results suggest that the generation of bridging ligands is essential to the sensitization of metal oxide nanocluster resists. Both low-energy electrons and radical cations can trigger dimerization. The diffusion of small radicals should be suppressed to prevent dimerization at undesired places.

X-Ray Induced Chemical Reaction Revealed by In Situ X-Ray Diffraction and Scanning X-Ray Microscopy in 15 nm Resolution

Abstract The detection sensitivity of synchrotron-based X-ray techniques has been largely improved due to the ever-increasing source brightness, which has significantly advanced ex situ and in situ research for energy materials such as lithium-ion batteries. However, the strong beam–material interaction arising from the high beam flux can substantially modify the material structure. The beam-induced parasitic effect inevitably interferes with the intrinsic material property, making the interpretation of the experimental results difficult and requiring comprehensive assessments. Here, we present a quantitative study of the beam effect on an electrode material Ag2VO2PO4 using four different X-ray characterization methods with different radiation dose rates. The material system exhibits interesting and reversible radiation-induced thermal and chemical reactions, further evaluated under electron microscopy to illustrate the underlying mechanism. The work will provide a guideline for using synchrotron X-rays to distinguish the intrinsic behavior from extrinsic structure change of materials induced by X-rays.

Transient Radiation-Induced Berkelium(III) and Californium(III) Redox Chemistry in Aqueous Solution.

Despite the significant impact of radiation-induced redox reactions on the accessibility and lifetimes of actinide oxidation states, fundamental knowledge of aqueous actinide metal ion radiation chemistry is limited, especially for the late actinides. A quantitative understanding of these intrinsic radiation-induced processes is essential for investigating the fundamental properties of these actinides. We present here a picosecond electron pulse reaction kinetics study into the radiation-induced redox chemistry of trivalent berkelium (Bk(III)) and californium (Cf(III)) ions in acidic aqueous solutions at ambient temperature. New and first-of-a-kind, second-order rate coefficients are reported for the transient radical-induced reduction of Bk(III) and Cf(III) by the hydrated electron (eaq-) and hydrogen atom (H•), demonstrating a significant reactivity (up to 1011 M-1 s-1) indicative of a preference of these metals to adopt divalent states. Additionally, we report the first-ever second-order rate coefficients for the transient radical-induced oxidation of these elements by a reaction with hydroxyl (•OH) and nitrate (NO3•) radicals, which also exhibited fast reactivity (ca. 108 M-1 s-1). Transient Cf(II), Cf(IV), and Bk(IV) absorption spectra are also reported. Overall, the presented data highlight the existence of rich, complex, intrinsic late actinide radiation-induced redox chemistry that has the potential to influence the findings of other areas of actinide science.

Aloe vera and the bitter truth

Probably best known for soothing the pain of sunburns, aloe vera is a cactus-like plant favored not just for burns but also for acne, eczema, oral submucous fibrosis, and radiation-induced skin reactions. Aloe vera juice is promoted as a low-calorie drink that clears up skin, relieves constipation, reduces heartburn, and improves eye health. But is aloe really a magic cure-all?

Radiation-Induced Reaction Kinetics of Zn2+ with eS - and Cl2 - in Molten LiCl-KCl Eutectic at 400-600 °C

Radiation-Induced Reaction Kinetics of Zn2+ with eS - and Cl2 - in Molten LiCl-KCl Eutectic at 400-600 °C

MRI-based contrast clearance analysis shows high differentiation accuracy between radiation-induced reactions and progressive disease after cranial radiotherapy

BackgroundPseudoprogression (PsP) or radiation necrosis (RN) may frequently occur after cranial radiotherapy and show a similar imaging pattern compared with progressive disease (PD). We aimed to evaluate the diagnostic accuracy of magnetic resonance imaging-based contrast clearance analysis (CCA) in this clinical setting.Patients and methodsPatients with equivocal imaging findings after cranial radiotherapy were consecutively included into this monocentric prospective study. CCA was carried out by software-based automated subtraction of imaging features in late versus early T1-weighted sequences after contrast agent application. Two experienced neuroradiologists evaluated CCA with respect to PsP/RN and PD being blinded for histological findings. The radiological assessment was compared with the histopathological results, and its accuracy was calculated statistically.ResultsA total of 33 patients were included; 16 (48.5%) were treated because of a primary brain tumor (BT), and 17 (51.1%) because of a secondary BT. In one patient, CCA was technically infeasible. The accuracy of CCA in predicting the histological result was 0.84 [95% confidence interval (CI) 0.67-0.95; one-sided P = 0.051; n = 32]. Sensitivity and specificity of CCA were 0.93 (95% CI 0.66-1.00) and 0.78 (95% CI 0.52-0.94), respectively. The accuracy in patients with secondary BTs was 0.94 (95% CI 0.71-1.00) and nonsignificantly higher compared with patients with primary BT with an accuracy of 0.73 (95% CI 0.45-0.92), P = 0.16.ConclusionsIn this study, CCA was a highly accurate, easy, and helpful method for distinguishing PsP or RN from PD after cranial radiotherapy, especially in patients with secondary tumors after radiosurgical treatment.

Decarboxylation efficiency of carboxylic acids as ligands of metal oxide nanocluster resists upon γ-ray irradiation

Metal oxide nanocluster resists have recently attracted considerable attention for use in extreme ultraviolet lithography. To obtain sophisticated guidelines for material design, it is necessary to understand well the radiation-induced chemical reaction scheme including the insolubilization mechanism. In this study, the production of CO2, which is considered to be one of the end products of treatment with an ionizing radiation, was investigated for eight types of carboxylic acid under various conditions using γ-rays (60Co) as a radiation source. The amount of CO2 produced was measured by gas chromatography. G CO2 (/100 eV), which indicates decarboxylation efficiency, was evaluated. CO2 was generated through electron addition, hole transfer, and hydroxyl radical addition to the molecular and ionic forms of carboxylic acids. The dependences of G CO2 on reaction partners were clarified. The dependences of G CO2 on the molecular structure and dissociative state of carboxylic acids were also clarified.

Mechanical properties, thermal stability and microstructure evolution of carbon fiber-reinforced epoxy composites exposed to high-dose γ-rays

Carbon fiber-reinforced composites with superior strength-to-weight and stiffness-to-weight ratio were highly resistant to ionizing radiation, which make them popular in nuclear reactor. There were large doses of γ-radiation in nuclear reactor, which caused damage in composites. In order to investigate effect of high γ-ray absorbed dose on carbon fiber (CF)/epoxy (EP) composite, the doses of 2 MGy, 7 MGy, and 20 MGy were applied in irradiating the samples, and the mechanical properties, thermal stability and microstructural changes of composites were analyzed. The results showed that under the absorbed dose of 2 MGy, the storage modulus, flexural strength and thermal stability of CF/EP composites increased. However, those properties decreased while the dose increased to 7 MGy and further decreased while the dose rise to 20 MGy. The evolution mechanism was understood by analyzing free radical and composition change of CF/EP after irradiation via electron spin resonance and X-ray photoelectron spectroscopy. Irradiation results in bond-breaking such as C–C bond and C–H bond, and also new bond-forming like C–O and CO, which forms competition effects among radiation-induced degradation and cross-linking reaction.