Beam Irradiation Time Research Articles

In-target production of [11C]CH4 from a nitrogen/hydrogen gas target as a function of beam current, irradiation time, and target temperature

BackgroundProduction of [11C]CH4 from gas targets is notorious for weak performance with respect to yield, especially when using high beam currents. Post-target conversion of [11C]CO2 to [11C]CH4 is a widely used roundabout method in 11C-radiochemistry, but the added complexity increase the challenge to control carrier carbon. Thus in-target-produced [11C]CH4 is superior with respect to molar activity. We studied the in-target production of [11C]CO2 and [11C]CH4 from nitrogen gas targets as a function of beam current, irradiation time, and target temperature.Results[11C]CO2 production was practically unchanged across the range of varied parameters, but the [11C]CH4 yield, presented in terms of saturation yield YSAT(11CH4), had a negative correlation with beam current and a positive correlation with target chamber temperature. A formulated model equation indicates behavior where the [11C]CH4 formation follows a parabolic graph as a function of beam current. The negative square term, i.e., the yield loss, is postulated to arise from Haber–Bosch-like NH3 formation: N2 + 3H2 → 2NH3. The studied conditions suggest that the NH3 (liq.) would be condensed on the target chamber walls, thus depleting the hydrogen reserve needed for the conversion of nascent 11C to [11C]CH4.Conclusions[11C]CH4 production can be improved by increasing the target chamber temperature, which is presented in a mathematical formula. Our observations have implications for targetry design (geometry, gas volume and composition, pressure) and irradiation conditions, providing specific knowledge to enhance [11C]CH4 production at high beam currents. Increased [11C]CH4 radioactivity is an obvious benefit in radiosynthesis in terms of product yield and molar radioactivity.

Surface-activated direct bonding of diamond (100) and c-plane sapphire with high transparency for quantum applications

Surface-activated direct bonding of diamond (100) and c-plane sapphire substrates is investigated using Ar atom beam irradiation and high-pressure contact at RT. The success probability of bonding strongly depends on the surface properties, i.e, atomic smoothness for the micron-order area and global flatness for the entire substrate. Structural analysis reveals that transformation from sapphire to Al-rich amorphous layer is key to obtaining stable bonding. The beam irradiation time has optimal conditions for sufficiently strong bonding, and strong bonding with a shear strength of more than 14 MPa is successfully realized. Moreover, by evaluating the photoluminescence of nitrogen-vacancy centers in the diamond substrate, the bonding interface is confirmed to have high transparency in the visible wavelength region. These results indicate that the method used in this work is a promising fabrication platform for quantum modules using diamonds.

Bi-criteria Pareto optimization to balance irradiation time and dosimetric objectives in proton arc therapy

Objective. Proton arc therapy (PAT) is a new delivery technique that exploits the continuous rotation of the gantry to distribute the therapeutic dose over many angular windows instead of using a few static fields, as in conventional (intensity-modulated) proton therapy. Although coming along with many potential clinical and dosimetric benefits, PAT has also raised a new optimization challenge. In addition to the dosimetric goals, the beam delivery time (BDT) needs to be considered in the objective function. Considering this bi-objective formulation, the task of finding a good compromise with appropriate weighting factors can turn out to be cumbersome. Approach. We have computed Pareto-optimal plans for three disease sites: a brain, a lung, and a liver, following a method of iteratively choosing weight vectors to approximate the Pareto front with few points. Mixed-integer programming (MIP) was selected to state the bi-criteria PAT problem and to find Pareto optimal points with a suited solver. Main results. The trade-offs between plan quality and beam irradiation time (static BDT) are investigated by inspecting three plans from the Pareto front. The latter are carefully picked to demonstrate significant differences in dose distribution and delivery time depending on their location on the frontier. The results were benchmarked against IMPT and SPArc plans showing the strength of degrees of freedom coming along with MIP optimization. Significance. This paper presents for the first time the application of bi-criteria optimization to the PAT problem, which eventually permits the planners to select the best treatment strategy according to the patient conditions and clinical resources available.

Effect of specimen processing for transmission electron microscopy on lattice spacing variation in Si specimens

Variation in the (220) lattice spacing of Si due to specimen processing for transmission electron microscopy (TEM) was experimentally evaluated by comparing the measured lattice spacings of crystalline specimens processed by crushing, mechanical polishing only, and combined mechanical and Ar ion polishing. Although distinct variation in the (220) lattice spacing between the Si specimens processed by crushing and by mechanical polishing only is not observed, the (220) lattice spacing of specimens prepared by combined mechanical and Ar ion polishing imply increasing tendency with increasing Ar ion beam irradiation time. Moreover, the (220) lattice spacing measured from the outermost region of the specimen edge tends to be approximately 3% to 5% larger than that measured from the inner region, irrespective of the processing method. These results demonstrate that differences in the processing conditions of Si specimens and in the measurement location of the Si lattice spacing can be major component of the measurement uncertainty in sub-nanometer metrology using TEM with magnification calibration by the Si lattice spacing. When attempting to apply the lattice spacing of Si as a reference with traceability to the International System of Units for TEM magnification calibration in sub-nanometer metrology, the results suggest that the effect of specimen processing on variation in the lattice spacing is not negligible.

Anisotropy and surface morphology of polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene thin layer irradiated with ion beam

ABSTRACT In this study, the surface modification and liquid crystal alignment characteristics of polystyrene-block-poly(ethylene-ran-butylene)-block- polystyrene (SEBS) coated glass substrates were analysed by varying the ion beam irradiation time. For the determination of the liquid crystal alignment characteristics, polarised optical microscopy was observed, and transmittance and pretilt angle were also measured. For the ascertainment of changes on the film surface, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) analysis were conducted. AFM analysis showed changes in peaks on the film surface and the formation of wrinkled structures, and XPS analysis showed that the element ratio of the surface and the bonding structure changed, leading to strong dipole-dipole interaction that enhanced liquid crystal alignment characteristics. Notably, ion beam irradiation rendered the surface anisotropic, resulting in the liquid crystal molecules being aligned in one direction, and the orientation was stronger than the effect of the wrinkled structures.

On the interplay effect for moving targets treated with the CyberKnife static tracking system.

To assess the interplay effect amplitude between different planned MU distributions and respiratory patterns in the CyberKnife system when treating moving targets with static tracking technique. Small- and Large-Respiratory Motions (SRM and LRM) differing in amplitude and frequency were simulated in a semi-anthropomorphic dynamic thorax phantom. The interplay effect was evaluated for both respiration motions in terms of GTV coverage and conformity for three plans designed with an increasing range of MU per beam (small, medium and large). Each plan was delivered three times changing the initial beam-on phase to assess the inter-fraction variation. Dose distributions were measured using radiochromic films placed in the GTV axial and sagittal planes. Generally, SRM plans gave higher GTV coverage and were less dependent on beam-on phases than LRM plans. For SRM (LRM) plans, the GTV coverage ranged from 95.2% to 99.7% (85.9% to 99.8%). Maximum GTV coverage was found for large MU plans in SRM and for small MU plans in LRM. Minimum GTV coverage was found for medium MU plans for both SRM and LRM. For SRM plans, dose conformity decreased with increasing MU range while the variation was reduced for LRM plans. Large MU plans reduced the inter-fraction variation for SRM and LRM. We confirmed the interplay effect between target motion and beam irradiation time for CyberKnife static tracking. Plans with large MU per beam improved the GTV coverage for small motion amplitude and the inter-fraction dose variation for large motion amplitude.

Flexible welding of SiOx nanowire to macroporous carbon film and underlying new insights

With the continuous decreasing in sizes of functional materials and devices, people are being asked to perform a flexible, accurate, in-situ and non-thermal welding of nanowires at the nanoscale. In this work, a well deliberated procedure including three typical stages: sharpening, hooking and welding, was carried out in sequence by in-situ TEM to realize the high demand welding of SiOx nanowire to macroporous carbon film. It was found that the brittle SiOx nanowire was non-thermally softened under energetic e-beam irradiation, and the flexibility and accuracy of welding could be achieved by adjusting the beam spot size, irradiation location and irradiation time. It was demonstrated that the nanocurvature effect of SiOx nanowire and the ultra-fast energy deposition effect induced by energetic e-beam irradiation dominated the diffusion, evaporation and plastic flow of atoms and the resulting nanowire re-shaping and nanowelding processes. In contrast, the traditional knock-on mechanism and e-beam heating effect are inadequate to explain these phenomena. Therefore, such a study is crucial not only to the flexible technical controlling but also to the profound fundamental understanding of energetic e-beam-induced nanowire re-shaping and nanowelding.

Estimations of fluorine-18 production yields from 13-MeV proton bombardment of enriched water target

Fluorine-18 (18F) is a positron emitter frequently used in Positron Emission Tomography (PET) to assist in the staging of primary tumors, Recent research suggests that the positron emitting radionuclide can also be applied for pneumonia imaging caused by Covid-19 infection. In this work, a 13-MeV proton beam was theoretically bombarded to 99.5% enriched water (H2 18O) target to produce 18F radionuclide via (p, n) nuclear reaction. The CalcuYield code was used in the predictions of the F-18 production yields. Using the CalcuYield code, the 18F radioactivity yields were calculated at the end of bombardment (EOB) at various proton beam currents, irradiation time and proton beam doses. Based on the CalcuYield calculated results, the maximum EOB yield of 18F at 13 MeV proton energy was 60.073 mCi/µAh. At a proton dose of 60 µAh, the EOB yield could be achieved as high as 3784.393 mCi, which could be used to diagnose more than 500 patients. The calculations also found that for the same proton dose, increasing proton beam current would result in greater 18F radioactivity yield than increasing irradiation time. In addition, radionuclide impurities which could predictably be present in the target were mostly due to nuclear reactions between proton beam and havar window. The predicted radionuclide impurities include 96Tc, 55Fe, 59Ni, 56Co, 52Mn, 186Re and 58Cu which were due to (p, n) nuclear reactions. The total radionuclide impurity yield was found to be 0.793 mCi/µAh. Among the other impurities, 58Cu was expected to have the highest radioactivity yield at all irradiation parameters. These predicted results could be used as a reference for future 18F radionuclide production should a 13-MeV proton beam is employed.

Cathodoluminescence Spectroscopic Stress Analysis for Silicon Oxide Film and Its Damage Evaluation.

We describe the stress analysis of silicon oxide (SiO2) thin film using cathodoluminescence (CL) spectroscopy and discuss its availability in this paper. To directly measure the CL spectra of the film under uniaxial tensile stresses, specially developed uniaxial tensile test equipment is used in a scanning electron microscope (SEM) equipped with a CL system. As tensile stress increases, the peak position and intensity proportionally increase. This indicates that CL spectroscopy is available as a stress measurement tool for SiO2 film. However, the electron beam (EB) irradiation time influences the intensity and full width at half maximum (FWHM), which implies that some damage originating from EB irradiation accumulates in the film. The analyses using Raman spectroscopy and transmission electron microscopy (TEM) demonstrate that EB irradiation for stress measurement with CL induces the formation of silicon (Si) nanocrystals into SiO2 film, indicating that CL stress analysis of the film is not nondestructive, but destructive inspection.

Design of beam instrumentation for in-vacuum materials irradiation and testing in a 30 MeV medical cyclotron

We summarize the studies carried out in Turkish Atomic Energy Authority Proton Accelerator Facility (TAEA PAF) R&D irradiation vault in order to design an in-vacuum fully automated irradiation system capable of adjusting proton beam energy between 2–30 MeV with beam currents down to picoamperes. The low current beam may be used for a wide range of research covering radiation damage testing and non-destructive material analysis such as PIXE, PIGE and RBS. The energy and current of the beam extracted TAEA-PAF cyclotron are not suitable to perform aforementioned applications since the accelerator was primarily designed for radioisotope production. Additional systems such as an energy degrader system, a collimator, an irradiation chamber and a Faraday Cup was designed in order to adjust beam parameters. The effects of different degrader foil materials, thicknesses, configurations and different collimator apertures on the beam energy and current at the target plane were investigated in the design of the energy degrader system. The temperature increase and activation of degrader foils were calculated depending on beam current and irradiation time. The design includes an energy measurement system with a Si(Li) detector. The design of the irradiation chamber includes equipment for beam characterization and sample manipulation and connection ports for detectors, pneumatic cylinders, motors and vacuum components. A Faraday Cup and related low noise electronics were designed, manufactured and tested. Picoampere range beam current was measured successfully with the Faraday Cup and related electronics for design validation.

Comparison of 192Os(p,n)192Ir and 192Os(d,2n)192Ir Nuclear Reactions for 192Ir Production

Iridium-192 ( 192 Ir ) is a radionuclide currently suggested for brachyteraphy. One of the methods employed to produce high purity 192 Ir is by irradiation of Osmium-192 ( 192 Os) target using cyclotron. The success of 192 Ir radionuclide production in cyclotrons requires deep understanding of irradiation parameters, including particle energy, target preparation and thickness, particle beam curent and irradiation time. Therefore, theoretical calculations of the 192 Ir radioactivity yields should be carried out as a preliminary measure for more efficient 192 Ir production. In this study, 192 Ir production was simulated using the SRIM 2013 program to determine the optimum target thickness while the nuclear cross-section data were extracted from TENDL 2017. Two nuclear reactions for 192 Ir production yield calculations were compared, i.e., 192 Os(p,n) 192 Ir and 192 Os(d,2n) 192 Ir. The radioactivity yields for 192 Os(p,n) 192 Ir nuclear reaction was found to be lower than 192 Os(d,2n) 192 Ir reaction. For proton and deuteron energy of 30 MeV, the maximum radioactivity yield was 6.79 GBq for 192 Os(p,n) 192 Ir and 26.14 GBq for 192 Os(d,2n) 192 Ir. Several radionuclide impurities such as 191m Ir, 190 Ir, 191 Os and 189 Re were predicted to be generated during 192 Os(p,n) 192 Ir reaction for proton incident energy between 1 and 30 MeV; meanwhile, 192 Ir, 191m Ir, 193 Os, 193m Ir, 192m Os and 191 Os radionuclides were expected to contaminate during 192 Os(d,2n) 192 Ir reaction for deuteron energy between 1 and 30 MeV. Results of this study can be used as a reference for future 192 Ir radionuclide production when proton or deuteron beams are considered to be employed. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif"; mso-ansi-language:EN-US; mso-fareast-language:EN-US;}

Research on radiation dose rate distribution in the backscattering neutron hall of CSNS

To evaluate the prompt and induced dose rate in backscattering neutron hall for radiation protection and safety management. The dose rates were calculated by Monte Carlo code FLUKA, with the “multi-step” simulation method based on traditional “two-step simulation” method. Operation time of staff workers does not need to be restricted. But with the increase in beam power and irradiation time, serious consideration might need to be taken as the dose rate of samples may be higher than the limit value.

Evolution of amorphous boron transformed into crystal nanospheres under electron beam irradiation

In this work, amorphous coralloid boron was successfully prepared in Cu-B-Mg alloy by adding magnesium and increasing cooling rate. Coralloid amorphous boron crystallized under electron beam irradiation and crystalline boron nanospheres were formed on amorphous substrate. The boron nanospheres possess a particle size between 5 and 20 nm. Boron nanospheres mainly exist as α-B structure. During the formation of boron sphere, a spherical black region was first formed in the amorphous boron substrate, and then the black region gradually crystallized and finally formed a complete boron sphere. Moreover, boron nanospheres were unstable in the initial stage and twin structure can be observed in this stage. As the electron beam irradiation time increased, the substrate gradually shrinked and the boron spheres gradually detached from the substrate.

Role of Hierarchical Protrusions in Water Repellent Superhydrophobic PTFE Surface Produced by Low Energy Ion Beam Irradiation

The surface wettability of polytetrafluoroethylene (PTFE) was investigated with low energy Ar+ ion beam irradiation varied from 300 eV to 800 eV both at normal and oblique angle of incidence (0°–70°) and at a low irradiation time of few 10 s of seconds. A remarkable change in surface wettability was observed, surface became hydrophobic to superhydrophobic just at 800 eV energy and in 30 s time. A systematic increase in the contact angle was observed with increase in beam energy and irradiation time. For a given ion energy and a threshold irradiation time, the hierarchical protrusions developed that leads to the rolling and bouncing of water droplet even on the horizontal PTFE surface. For the above energy range, the rolling speed was found to be in the range of ~19–31 mm/s. This induced wetting behaviour due to ion irradiation leads to the Cassie-Baxter state as confirmed by the calculation of sliding angle, contact angle hysteresis (CAH) and surface free energy (SE). The CAH values were found to be reduced from 18° for untreated surface (SE ~ 20 mN/m) to 2° for 800 eV, 180 s irradiated surface (SE ~ 0.35 mN/m) at normal incidence.

Cyclotron production of 68Ga in a liquid target: Effects of solution composition and irradiation parameters

ObjectivesTo optimize 68Ga production using a liquid cyclotron target, investigations were performed to compare production yields using different concentrations of [68Zn]Zn(NO3)2, nitric acid, and irradiation parameters. MethodsDifferent concentrations of [68Zn]Zn(NO3)2 (0.6 M, 1.2 M and 1.42 M) in varying normality of nitric acid (0.8–1.5 N) were prepared and irradiated with protons (incident energy ~14 MeV) using a BMLT-2 liquid target at different beam currents (30–50 μA) and irradiation times (30–60 min). The 68Ga production and saturation yields were calculated and compared. [68Ga]GaCl3 was isolated using in-house developed hydroxamate resin and optimized for routine application. Recycling of [68Zn]Zn(NO3)2 from the recovered target solution was also investigated. ResultsOn increasing concentration of [68Zn]Zn(NO3)2 from 0.6 M to 1.2 M in 0.8 N nitric acid, decay corrected yield of 68Ga at EOB was found to be 1.64 GBq (44.4 mCi) and 3.37 GBq (91.0 mCi), respectively at 30 μA beam current, indicating production yield was proportional to zinc nitrate concentration for a 30 min irradiation. However, when beam current was increased to 40 μA while maintaining nitric acid concentration at 0.8 N, the proportional relationship of 68Zn-concentration with 68Ga production yield was lost [0.6 M, 2.29 GBq (61.9 mCi); 1.2 M, 3.6 GBq (97.3 mCi)] for a 30 min irradiation. In fact, the effect was more profound for 60 min irradiations [0.6 M, 2.96 GBq (80.0 mCi); 1.2 M, 4.25 GBq (115 mCi)]. Increasing nitric acid concentration to 1.25–1.5 N improved 68Ga production yield for 40 μA, 60-min irradiations (1.2 M; 5.17 GBq (140 mCi)). MP-AES analysis showed metal impurities as <0.20 μg Ga (n = 3), <0.93 μg Zn (n = 3) and < 2.7 μg Fe (n = 3). Based on above finding, 1.42 M [68Zn]Zn(NO3)2 in 1.2 N-HNO3 solutions were also studied to achieve highest production yields of 9.85 ± 2.09 GBq (266 ± 57 mCi) for 60 min irradiation at 40 μA beam current. After recycling,> 99% pure recycled [68Zn]zinc nitrate was obtained in 82.6 ± 13.6% yield. Conclusions68Ga production yields were dependent on all four variables: concentrations of [68Zn]Zn(NO3)2 and nitric acid, beam current and duration of irradiation. Of note, increasing beam current and irradiation time may require increased concentrations of nitric acid to achieve expected increments in 68Ga production yield.

Rapid stabilization of polyacrylonitrile fibers achieved by plasma-assisted thermal treatment on electron-beam irradiated fibers

In the manufacturing process of polyacrylonitrile (PAN) based carbon fiber (CF), stabilization, is crucial to both process efficiency and the mechanical properties of CFs. Highly effective stabilization was successfully demonstrated by plasma-assisted thermal treatment (PT) on electron-beam irradiated PAN fibers. The method was remarkably efficient to prepare carbonizable fibers within a total stabilization time of 13.3min, which includes electron beam irradiation (3.3min) and PT time (10min). We believe that such a fast stabilization was achieved by coaction of diffusive and reactive oxygen species from atmospheric plasma source with oxygen-favored radicals introduced by pre-treatment of electron-beam irradiation.

A Review of Ion Implantation Technology for Image Sensors †.

Ion implantation technology is reviewed mainly from the viewpoint of image sensors, which play a significant role in implantation technology development. Image sensors are so sensitive to metal contamination that they can detect even one metal atom per pixel. To reduce the metal contamination, the plasma shower using RF (radio frequency) plasma generation is a representative example. The electrostatic angular energy filter after the mass analyzing magnet is a highly effective method to remove energetic metal contamination. The protection layer on the silicon is needed to protect the silicon wafer against the physisorbed metals. The thickness of the protection layer should be determined by considering the knock-on depth. The damage by ion implantation also causes blemishes. It becomes larger in the following conditions if the other conditions are the same; a. higher energy; b. larger dose; c. smaller beam size (higher beam current density); d. longer ion beam irradiation time; e. larger ion mass. To reduce channeling, the most effective method is to choose proper tilt and twist angles. For P+ pinning layer formation, the low-energy B+ implantation method might have less metal contamination and damage, compared with the BF2+ method.

Scanned carbon-ion beam therapy throughput over the first 7 years at National Institute of Radiological Sciences

IntroductionIn the 7 years since our facility opened, we have treated >2000 patients with pencil-beam scanned carbon-ion beam therapy. MethodsTo summarize treatment workflow, we evaluated the following five metrics: i) total number of treated patients; ii) treatment planning time, not including contouring procedure; iii) quality assurance (QA) time (daily and patient-specific); iv) treatment room occupancy time, including patient setup, preparation time, and beam irradiation time; and v) daily treatment hours. These were derived from the oncology information system and patient handling system log files. ResultsThe annual number of treated patients reached 594, 7 years from the facility startup, using two treatment rooms. Mean treatment planning time was 6.0 h (minimum: 3.4 h for prostate, maximum: 9.3 h for esophagus). Mean time devoted to daily QA and patient-specific QA were 22 min and 13.5 min per port, respectively, for the irradiation beam system. Room occupancy time was 14.5 min without gating for the first year, improving to 9.2 min (8.2 min without gating and 12.8 min with gating) in the second. At full capacity, the system ran for 7.5 h per day. ConclusionsWe are now capable of treating approximately 600 patients per year in two treatment rooms. Accounting for the staff working time, this performance appears reasonable compared to the other facilities.

Sperm motility is enhanced by Low Level Laser and Light Emitting Diode photobiomodulation with a dose-dependent response and differential effects in fresh and frozen samples.

The effects of Low Level Light Therapy (LLLT) on cellular function arise predominantly from stimulation of ATP production and reduction of oxidative stress. These effects are dose dependent and a function of beam irradiance and irradiation time. Human sperm motility has been shown to increase with LLLT irradiation. The objective of this study was to investigate the effects of laser and Light Emitting Diode (LED) LLLT photobiomodulation on human spermatozoa motility and DNA integrity. An in-vitro controlled trial was performed within an IVF clinic laboratory using three human semen specimens, one fresh and two frozen. Sperm were exposed to light from a GaAlAs single laser (810 nm 200 mW) and an LED cluster (660 nm and 850 nm total power 2 W) for various irradiation times. Sperm motility for the test and control aliquots was assessed using a SQA-IIB analyser, but fertilizing ability was not. Sperm chromatin integrity was tested using the Sperm Chromatin Structure Assay. The Sperm Motility Index and Total Functional Sperm Count increased up to four fold compared to controls with inhibitory effects observed at higher doses (longer irradiation times). The maximum effect varied with irradiance and irradiation time and whether the sample was fresh or frozen. Human sperm motility is modified by exposure to LLLT and this motility modification is dependent upon beam irradiance and irradiation time as well as the condition of the sample. A higher stimulatory dose provides a rapid increase in motility that is short in duration, while a lower stimulatory dose provides a slower increase in motility. An inhibitory does causes reduced motility. Future research could consider animal models, such as the mouse, to test fertilization capacity and the safety of resulting fetuses.

Probing the electron beam induced reduction of graphite oxide by in situ X-ray photoelectron spectroscopy/mass spectrometer

Abstract The graphite oxide (GO) was reduced successfully by electron-beam irradiation without solution chemistry and high temperature, where the chemical structural changes and gaseous species released during the exposure was monitored directly by X-ray photoelectron spectroscopy/mass spectrometer. The degree of reduction of GO can be tuned effectively by way of electron beam intensity and irradiation time, resulting a high C/O ratio of 5.27. The evolution of C 1s spectra with irradiation time was also investigated. The CO, CO2, H2 molecules and several organic species were detected during the irradiation, confirmed that the electron beam induced the photoreduction of GO. The combined chemical structure evolution and gas species analysis make the XPS-MS highly desirable as a powerful in situ analytical instrument for tracking the reaction process. The electron-beam-induced reduction described in detail here provides potential way to fabricate graphene device from GO in one step.