scholarly journals Filament X-ray Tube Current Control Method Using Indirect Filament Temperature Estimation

2021 ◽  
Vol 11 (22) ◽  
pp. 10588
Author(s):  
Je-Jin Jang ◽  
He-Lin Zhu ◽  
Hyung-Soo Mok
Keyword(s):  
Dose Rate ◽  
Temperature Control ◽  
Control Method ◽  
Estimation Algorithm ◽  
Current Control ◽  
X Rays ◽  
Temperature Estimation ◽  
X Ray ◽  
Filament Temperature ◽  
Tube Current

The recent increase in ailments has increased the demand for diagnosis and surgery based on X-rays. An X-ray system using a filament-type tube heats the filament for operation, and the electrons emitted by the thermal energy during this process produce X-rays. Conventionally, current control-based methods are used to regulate heating. However, these methods do not control the temperature of the filament, resulting in lower or higher output than the desired dose rate. Therefore, we propose a filament temperature control method that enables constant temperature control, which cannot be achieved using the existing heating method for X-ray systems with filament tubes. Additionally, we developed an indirect temperature estimation algorithm for the tungsten filament to incorporate the proposed method. To validate the tube current control through temperature control, we performed experiments to compare the existing current-controlled heating and temperature control methods in terms of the filament temperature. As the tube current is proportional to the dose rate, it was measured through a comparative analysis of the change in the output of dose rate over time. The obtained results validate that the proposed method can maintain both the filament temperature and tube current at the desired level.

New Rotating Anode X-Ray Generator For XAFS Experiments

1995 ◽  
Vol 39 ◽  
pp. 149-153
Author(s):  
Kenji Sakurai
Keyword(s):  
High Vacuum ◽  
Lanthanum Hexaboride ◽  
X Rays ◽  
Tube Voltage ◽  
X Ray ◽  
Low Tube Voltage ◽  
Tube Current ◽  
Sample Position ◽  
Good Energy ◽  
X Ray Absorption

A high-power X-ray generator equipped with a lanthanum hexaboride cathode has been developed for X-ray absorption fine structure experiments. A high tube-current of more than 1,000 mA can be provided when operated at low tube-voltage of less than 20 kV. In addition, the focal width is narrow enough (less than 0.1 mm) to ensure good energy resolution. Extremely intense monochromatic X-rays (106 ∼ 107 counts/(sec.mm2) at the sample position), which are completely free from higher order harmonics and tungsten contamination lines, are available, when a Johansson-type spectrometer is employed. The filament life has been significantly prolonged by the high vacuum specification of the tube.

Radiation Exposure of Medical Personnel Accompanying the Patient during the Procedure of Superficial X-Ray Therapy of Children

2019 ◽  
Vol 64 (5) ◽  
pp. 54-57
Author(s):  
С. Смолин ◽  
S. Smolin
Keyword(s):  
Radiation Exposure ◽  
Effective Dose ◽  
Dose Rate ◽  
Medical Personnel ◽  
X Rays ◽  
X Ray ◽  
Treatment Room ◽  
Tissue Equivalent ◽  
Tissue Equivalent Phantom ◽  
Irradiation Process

Purpose: Assessment the radiation situation in the treatment room of superficial x-ray therapy during the irradiation process in order to inform about radiation exposure of medical personnel or a relatives. Material and methods: In the course of the study, a procedure of superficial radiotherapy was simulated using a tissue equivalent phantom with sizes 250×250×150 mm. The radiation control protocol of measurements on the Roentgen TA-02 apparatus was compiled on the basis of SanPiN 2.6.1.1192-03. With the help of a clinical dosimeter DKS-AT1123, the ambient dose-rate of short-term x-rays was measured. In accordance with the requirements for conducting radiation monitoring, measurements were taken directly near the apparatus in areas 60×60 cm at points located at heights corresponding to the head level (160 ± 20 cm), chest level (120 ± 20 cm), gonad level (80 ± 20 cm) and the level of the legs (30 ± 20 cm). On the basis of the obtained data, the value of the effective dose-rate of x-ray radiation for the whole human body was calculated for each area. Taking into account the characteristics of the irradiation regime used in the clinic, the total effective dose received by the medical personnel accompanying the patient for the entire course of radiotherapy was calculated. Results: A drawn up diagram is illustrating the radiation situation in the treatment room of superficial radiotherapy. Based on the results of calculations, it can be concluded that the radiation exposure on the accompanying person during superficial x-ray therapy of children’s hemangiomas does not exceed the maximum permissible dose specified in paragraph 5.4.4 of SanPiN 2.6.1.2523-09. Conclusion: In exceptional cases, a parent or medical personnel may be in the treatment room to support the patient.

Some factors in the design of hot cathode X-ray tubes for steady running

1932 ◽  
Vol 28 (4) ◽  
pp. 497-508
Author(s):  
W. R. Harper
Keyword(s):  
Negligible Effect ◽  
X Rays ◽  
Auxiliary Electrode ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Tube Current ◽  
Small Tube

Some general considerations regarding the design of hot cathode X-ray tubes for producing an accurately constant and repeatable beam of X-rays are first given. The construction of a tube in accordance with these considerations is then described. This tube has been used to show that except with small tube-currents the quality of the vacuum in such a tube has little influence on the steadiness of the beam if the electrical input to the tube can be satisfactorily controlled.It is shown that the X-radiation associated with the fluorescence often observed in X-ray tubes has usually but not always a negligible effect on the steadiness of the beam.Some factors limiting tube current when the filament is enclosed in a box containing a focussing slit are mentioned, and the mechanism of formation of the focus is discussed with reference to its size. The use of an auxiliary electrode to increase the tube current and improve the focussing is also discussed.

scholarly journals Radiosensitization by Gold Nanoparticles: Impact of the Size, Dose Rate, and Photon Energy

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 952 ◽  
Author(s):  
Kirill V. Morozov ◽  
Maria A. Kolyvanova ◽  
Maria E. Kartseva ◽  
Elena M. Shishmakova ◽  
Olga V. Dement’eva ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Dose Rate ◽  
Photon Energy ◽  
Fold Increase ◽  
X Rays ◽  
X Ray ◽  
Complex Dependence ◽  
Pbr322 Plasmid ◽  
First Time ◽  
Selection Of

Gold nanoparticles (GNPs) emerged as promising antitumor radiosensitizers. However, the complex dependence of GNPs radiosensitization on the irradiation conditions remains unclear. In the present study, we investigated the impacts of the dose rate and photon energy on damage of the pBR322 plasmid DNA exposed to X-rays in the presence of 12 nm, 15 nm, 21 nm, and 26 nm GNPs. The greatest radiosensitization was observed for 26 nm GNPs. The sensitizer enhancement ratio (SER) 2.74 ± 0.61 was observed at 200 kVp with 2.4 mg/mL GNPs. Reduction of X-ray tube voltage to 150 and 100 kVp led to a smaller effect. We demonstrate for the first time that the change of the dose rate differentially influences on radiosensitization by GNPs of various sizes. For 12 nm, an increase in the dose rate from 0.2 to 2.1 Gy/min led to a ~1.13-fold increase in radiosensitization. No differences in the effect of 15 nm GNPs was found within the 0.85–2.1 Gy/min range. For 21 nm and 26 nm GNPs, an enhanced radiosensitization was observed along with the decreased dose rate from 2.1 to 0.2 Gy/min. Thus, GNPs are an effective tool for increasing the efficacy of orthovoltage X-ray exposure. However, careful selection of irradiation conditions is a key prerequisite for optimal radiosensitization efficacy.

scholarly journals SECONDARY RADIATION MAPPING

2021 ◽  
pp. 162-166
Author(s):  
Ioannis Vlachos ◽  
Ioannis Kandarakis ◽  
Giorgos Panayiotakis
Keyword(s):  
Dose Rate ◽  
Radiation Protection ◽  
Secondary Radiation ◽  
X Rays ◽  
Scatter Radiation ◽  
X Ray ◽  
Vital Importance ◽  
Water Phantom ◽  
The Mean ◽  
Secondary Dose

Radiation protection for personnel working with X-rays is of vital importance. Several studies have been published regarding the secondary radiation and the shielding requirements to areas that are adjacent to the X-ray units. In this work, secondary radiation in a conventional radiographic room, in terms of dose rate (mSv/hr), as a function of different radiographic exposure factors has been studied. The measurements were performed with a 451P Fluke Biomedical survey meter on a Philips Medio 65 CP-H X-ray generator with a cylindrical water phantom. It was found that the dose rate from the scatter radiation decreases with distance. An added filtration of 2.0 mmAl at 100 kVp reduced the secondary dose rate further by 21.4%. The results of this study may be of value during exposure of personnel that are not protected by shielding materials. Highlights Ÿ It was found that the dose rate from the scatter radiation decreases with distance. An added filtration of 2.0 mmAl at 100 kVp reduced the secondary dose rate further by 21.4%. Ÿ The mean secondary X-ray energies for 60, 80, 100 and 100 kV with 2 mmAl added, were calculated as 34.41, 51.12, 69.03 and 71.29 keV respectively. Ÿ The results of this study are of value during exposure of people such as radiographers, and patients during the use of mobile X-ray units.

Rare-Earth Analyses by X-Ray-Excited Optical Fluorescence

1967 ◽  
Vol 11 ◽  
pp. 204-213
Author(s):  
W. E. Burke ◽  
D. L. Wood
Keyword(s):  
Rare Earth ◽  
Target Material ◽  
Energy Output ◽  
X Rays ◽  
X Ray ◽  
Tungsten Target ◽  
Low Concentrations ◽  
Tube Current ◽  
Optical Fluorescence ◽  
Optical Line

AbstractX-ray excitation causes rare-earth impurities in yttrium oxide and gadolinium oxide to emit intense and highly characteristic optical line fluorescence, which enables their analyses at low concentrations. The limits of detection for praseodymium, ncodymium, samarium, europium, gadolinium, terbium, dysprosium. holmium, erbium, thulium, and ytterbium in these two oxides range from 1 to 100 parts per billion (ppb). In other rare-earth oxides which have been investigated. the fluorescent intensities arc greatly reduced. Successful analyses can be made only by dilution in high-purity Y2O3. This dilution raises the detection limits for rare earths in these other oxides to the part per million range. X-rays from the chromium target of a cual-target X-ray tube are about two times more efficient in exciting rareeaith optical fluorescence than are the tungsten-target X-rays, even though the total energy output of the chromium target is only about one-third that of the tungsten target. With either target material, the rare-earth intensities vary linearly with the X-ray tube current, but a plot of intensity versus the square of the accelerating potential is not linear; it drops off at higher voltages.

Microanalysis of crystalline phases in Tl-1223 superconducting wire using an x-ray microdiffractometer

1994 ◽  
Vol 9 (5) ◽  
pp. 1122-1125 ◽  
Author(s):  
Tatsumi Hirano ◽  
Katsuhisa Usami
Keyword(s):  
Control Method ◽  
Pressure Control ◽  
Crystal Structure Analysis ◽  
Stable Phase ◽  
Nominal Composition ◽  
Imaging Plate ◽  
Phase Reaction ◽  
X Rays ◽  
X Ray ◽  
Superconducting Wires

We developed an x-ray microdiffractometer using synchrotron radiation with which we analyzed microcrystal structures of heterogeneities in Tl-1223 superconducting wires prepared by different processes, i.e., partial melt and solid/liquid phase reaction. Samples with the nominal composition (Tl0.5Pb0.5)1(Sr0.8Ba0.2)2Ca2Cu3O9 were irradiated by focused SR x-rays of 6 μm × 8 μm size. The diffracted x-rays were two-dimensionally detected with an imaging plate. From crystal structure analysis, we identified the heterogeneities as BaPbO3 and (CaSr)2Cu1O3 which are present in Tl-1223 superconducting wires prepared by both processes. This suggested that these heterogeneous phases coexist with the stable phase in the Tl-1223 phase diagram. Consequently, it is necessary to develop a new processing method such as low temperature annealing or a suitable O2 pressure control method.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

1974 ◽  
Vol 32 ◽  
pp. 570-571
Author(s):  
R. H. Duff
Keyword(s):  
Species Identification ◽  
Valence Electron ◽  
Chemical Species ◽  
X Rays ◽  
Chemical Bonds ◽  
Small Shift ◽  
X Ray ◽  
Electron Transitions ◽  
Peak Energy ◽  
Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

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