Magnetic Scanning System Research Articles

Research on the technology of casing inspection through tubing in the Saertu Development Zone of Daqing Oilfield

With the further development of Daqing Oilfield, the occurrence of widespread casing damage in the Saertu Development Area has been on the rise annually.In order to promptly prevent, detect and address casing damage, the management departments of the oil extraction plants must schedule regular casing inspection operations. This approach not only raises production costs but also prolongs the well shutdown period, further impacting crude oil output.This article focuses on the technical needs of oilfield development and has developed tubing and casing detection technology, the radial magnetic scanning system is integrated with the sixteen arm wellbore diameter, the synchronous tubing and casing inspection instrument represents the latest in concurrent inspection technology, developed specifically for the technical demands of oilfield development Without displacing the tubing column, it simultaneously captures data on tubing inner diameter, tubing continuity, the extent of casing damage via magnetic scanning, and continuous 3D imaging of the tubing at standard inspection speeds, the workload of checking and matching tasks were significantly reduced. Between 2022 and 2023, the through-tubing casing inspection technology was utilized in 525 wells, with 356 wells verified by mobilizing the tubing column, achieving a predictive accuracy of 87.6% and generating economic benefits of 69.6 million yuan.

Study of irregular electron beam correcting permanent-magnet-quadrupole doublet lens for irradiation accelerator.

In this paper, a permanent-magnet-quadrupole doublet lens with strong-focusing is designed and manufactured. Such an instrument could solve the problem of irregular beam spots produced by the weak focusing of conventional solenoid-focusing systems in low-energy electron irradiation accelerators. It could provide a better and more appropriate initial beam spot before the beam enters the subsequent magnetic spreading system or magnetic scanning system, thus, improving the irradiation uniformity. The association of the parameters of the rectangular permanent magnet with the quadrupole magnetic field is investigated. Focusing results, obtained using irregular beam spots with different profiles and different energies, and magnetic field measurement results, both from the instrument, verify the engineering feasibility of this permanent-magnet-quadrupole doublet lens.

High resolution diagnostic tools for superconducting radio frequency cavities.

Superconducting radio-frequency (SRF) cavities are one of the fundamental building blocks of modern particle accelerators. To achieve the highest quality factors (1010-1011), SRF cavities are operated at liquid helium temperatures. Magnetic flux trapped on the surface of SRF cavities during cool-down below the critical temperature is one of the leading sources of residual RF losses. Instruments capable of detecting the distribution of trapped flux on the cavity surface are in high demand in order to better understand its relation to the cavity material, surface treatments and environmental conditions. We have designed, developed, and commissioned two high-resolution diagnostic tools to measure the distribution of trapped flux at the surface of SRF cavities. One is a magnetic field scanning system, which uses cryogenic Hall probes and anisotropic magnetoresistance sensors that fit the contour of a 1.3GHz cavity. This setup has a spatial resolution of ∼13μm in the azimuthal direction and ∼1 cm along the cavity contour. The second setup is a stationary, combined magnetic and temperature mapping system, which uses anisotropic magnetoresistance sensors and carbon resistor temperature sensors, covering the surface of a 3GHz SRF cavity. This system has a spatial resolution of 5mm close to the iris and 11mm at the equator. Initial results show a non-uniform distribution of trapped flux on the cavities' surfaces, dependent on the magnitude of the applied magnetic field during field-cooling below the critical temperature.

Power supply for fast-scanning magnet in proton therapy: Design and test

Proton therapy is one of the most effective radiation methods to combat cancer and offers a substantial advantage over conventional photon therapy. Magnetic scanning systems consisting of a magnet and power supply form an integral part of proton therapy and allow the beam position (x, y) to be controlled during spot scanning. Ensuring that the dose is rapidly and precisely distributed within the contour of the tumor requires a high-precision, fast-ramp-speed, and high-stability power supply with accurate control. The present work uses a three-phase bridge rectifier and multiple series-parallel H-bridge converters to propose a prototype power supply for the scanning magnet of a magnetic scanning system. The power supply is controlled using a proportional integral controller using digital signal processing. A prototype of the scanning power supply is developed and tested, and the results demonstrate an output current of ±500A, a ramp speed of ±40 kA/s, and a short- and long-term stability of less than 20 ppm.

Design and Commissioning of a Magnetic Field Scanning System for SRF Cavities

Design and Commissioning of a Magnetic Field Scanning System for SRF Cavities

Magnetic, in situ, mineral characterization of Chelyabinsk meteorite thin section

AbstractMagnetic images of Chelyabinsk meteorite's (fragment F1 removed from Chebarkul lake) thin section have been unraveled by a magnetic scanning system from Youngwood Science and Engineering (YSE) capable of resolving magnetic anomalies down to 10−3 mT range from about 0.3 mm distance between the probe and meteorite surface (resolution about 0.15 mm). Anomalies were produced repeatedly, each time after application of magnetic field pulse of varying amplitude and constant, normal or reversed, direction. This process resulted in both magnetizing and demagnetizing of the meteorite thin section, while keeping the magnetization vector in the plane of the thin section. Analysis of the magnetic data allows determination of coercivity of remanence (Bcr) for the magnetic sources in situ. Value of Bcr is critical for calculating magnetic forces applicable during missions to asteroids where gravity is compromised. Bcr was estimated by two methods. First method measured varying dipole magnetic field strength produced by each anomaly in the direction of magnetic pulses. Second method measured deflections of the dipole direction from the direction of magnetic pulses. Bcr of magnetic sources in Chelyabinsk meteorite ranges between 4 and 7 mT. These magnetic sources enter their saturation states when applying 40 mT external magnetic field pulse.

Scanning Properties of Dipole Bending Magnets used in Ion-Therapy Gantries

In modern ion-therapy facilities, there is a trend to develop and use scanning beam delivery systems. One of the most important advantages of scanning systems is that the field-shaping material devices in the beam path are minimized or removed entirely. Scanning systems inherently provide the intensity modulated radiation fields of ion beams that allow for a much greater flexibility in tailoring the dose distribution than in the case of passive delivery systems. A study of scanning properties of dipole bending magnets is published in order to provide engineers the theoretical tool for the early stage of a scanning-system design. This study is focused on scanning properties of dipole bending magnets with pure dipole fields without any gradient. The 90°, 60°, 45° and 30° bending magnets are studied. A two-directional magnetic scanning system with two scanners, one in the horizontal and another one in the vertical plane, is considered. This 2D magnetic scanning system ensures a parallel scanning mode in both transverse planes. The ion-optical properties of 2D magnetic scanning system and the study results for dipole bending magnets mentioned above are discussed.

First direct-write lithography results on the Guelph high resolution proton microprobe

The recently completed high-resolution proton microprobe at the University of Guelph is Canada’s first one-micron nuclear microprobe, which represents the country’s state-of-the-art technology for various nuclear microprobe applications, e.g. direct-write microlithography. Its probe-forming system is comprised of a triplet Oxford Micro beams magnetic quadrupole lenses, along with high-precision objective slits. High energy protons coming off a 3MV particle accelerator can achieve a nominal resolution of one micro and a beam current of several hundred of picoamperes when arriving at the target. This proton probe is ideal for the use of direct-write lithography with the incorporation of a magnetic scanning system and motorized sample stage.Preliminary lithography results have been obtained using spin-coated PMMA photoresist as specimen. The beam spot size, beam range and straggling inside the substrate and the exposure conditions are investigated by using scanning electron microscopy. This facility is the first in Canada to perform focused direct-write ion beam lithography, which is ideal for modification and machining of polymer and semiconductor materials for biological, microfluidic and ultimate lab-on-chip applications.

The UHV system of the 10 MeV RF electron linac

A 10 MeV, 10 kW RF Electron Linac, for Industrial applications, is installed and commissioned at Electron Beam Centre (EBC), Kharghar, Navi Mumbai. The accelerator consists of the electron gun, RF Linac, Vacuum system, Beam diagnostics system, Magnetic sweep scanning system and Scan horn. The accelerator is divided into three sections with gate valves to isolate them, to enable servicing of pumps and modifications. The vacuum requirement in the accelerator is 10−7 mbar considering the breakdown parameters of the RF field within the linac. Total length of the accelerator from electron gun to the scan horn is about 5.0 meters. Vacuum plumb lines are of SS 304 pipes of nominal bores of 100 mm and 150 mm, machined internally to a surface finish of 0.8 μm. It encloses a volume of 156 litres. Total surface area exposed to vacuum is 57,500 cm2. It consists of 5250 cm2 of OFHC Copper, 51300 cm2 of SS 304 and 940 cm2 of ceramic sections. Leak-tightness of the order of 1 × 10−9mbar.l/s is ensured for the whole system, after eliminating the leaks at every stage of the assembly. Baking the plumb line and pumps at 150° C, for eight hours an ultimate vacuum of 2 × 10−7mbar is achieved in the accelerator.Modifications of the vacuum system is undertaken to suit the design changes in the gun and the diagnostic systems.

217 Development of a scanning system for intensity modulated radiation therapy with photon pencil beams

The increasing cancer incidence requires more accurate and cost-effective diagnostic as well as therapeutic methods. Intensity modulated radiation therapy is now rapidly being introduced at many radiation therapy departments with a clear trend towards radiobiological treatment planning using 4D-diagnostic imaging and -treatment delivery. Therefore a magnetic system for scanning of narrow photon pencil beams has been developed for fast 4D-IMRT. The magnetic scanning system has been modelled in full 3D taken into account all aspects such as fringing field, magnetic leakage and cooling. The magnetic system consists of two perpendicular scanning magnets, a bending magnet and a purging magnet placed after a thin bremstrahlung target and in the same plane as the last scan magnet. The scanning magnets operate in orthogonal planes and the first scanning magnet (bending plane) is placed so that the image of its scanning centre lies near the effective centre of the second scan magnet (cross plane). In this way a very compact deflection system is obtained, with the position of the effective radiation source coinciding for the two orthogonal planes. The focus of the intrinsic electron beam is at the top of the target placed near the end of the last scanning magnet. The composition and thickness of this target determines the energy of the transmitted electrons and the full width half maximum (FWHM) of the photon beam. Here the target is made of 3 mm beryllium creating a therapeutic beam of 10-15 mm (FWHM) for an incident electron beam of 70-50 MeV. The transmitted electron beam has only lost around 0.5-1.0 MeV in the target and must be removed from the therapeutic beam. Therefore downstream of the target a strong and fast purging magnet integrated with an electron collector has been developed. The purging magnet operates in the same plane as the last scanning magnet and deflects the transmitted high energy electrons to the same area on the electron collector independent of the direction of the scanned photon beam. The overall design of the treatment head is compact and the narrow photon beam will allow a very accurate dose delivery particularly when combined with a thin efficient leaf collimator designed for pencil beam IMRT.

Online compensation for target motion with scanned particle beams: simulation environment

Target motion is one of the major limitations of each high precision radiation therapy. Using advanced active beam delivery techniques, such as the magnetic raster scanning system for particle irradiation, the interplay between time-dependent beam and target position heavily distorts the applied dose distribution. This paper presents a simulation environment in which the time-dependent effect of target motion on heavy-ion irradiation can be calculated with dynamically scanned ion beams. In an extension of the existing treatment planning software for ion irradiation of static targets (TRiP) at GSI, the expected dose distribution is calculated as the sum of several sub-distributions for single target motion states. To investigate active compensation for target motion by adapting the position of the therapeutic beam during irradiation, the planned beam positions can be altered during the calculation. Applying realistic parameters to the planned motion-compensation methods at GSI, the effect of target motion on the expected dose uniformity can be simulated for different target configurations and motion conditions. For the dynamic dose calculation, experimentally measured profiles of the beam extraction in time were used. Initial simulations show the feasibility and consistency of an active motion compensation with the magnetic scanning system and reveal some strategies to improve the dose homogeneity inside the moving target. The simulation environment presented here provides an effective means for evaluating the dose distribution for a moving target volume with and without motion compensation. It contributes a substantial basis for the experimental research on the irradiation of moving target volumes with scanned ion beams at GSI which will be presented in upcoming papers.

Solid State Analysis with the New Leipzig High-Energy Ion Nanoprobe

The high-energy ion nanoprobe LIPSION at the University of Leipzig has been operational since October 1998. The ultrastable single ended 3.5 MV SINLETRONTM accelerator supplies the H+ or He+ ion beam. A magnetic scanning system moves the focused beam across the sample. At present, a resolution of 150 nm in the low current mode and 300 nm at 5 pA could be achieved. The UHV grade experimental chamber is equipped with electron-, energy dispersive X-ray-, and particle detectors. They can be used simultaneously to analyse the sample by means of PIXE (particle induced X-ray emission), RBS (Rutherford backscattering) and in the case of thin samples STIM (scanning transmission ion microscopy). A goniometer allows the application of channeling measurements in single crystals in combination with these methods. The detection limits depend on the elements to be analysed and range from (1000⋯1) μg/g relative and (1⋯0.01) pg absolute. The analysis is nondestructive, but the sample has to be vacuum resistant. Applications of the nanoprobe in the field of semiconductor research, biomedicine, and archaeology will be described.

A design of a rotating gantry for non-symmetric ion-therapy beams

An ion-optical design of a gantry for transport of ion beams having different emittances in the horizontal and vertical plane is presented. The ion-optical constraints making the beam spot at the gantry exit independent from the angle of gantry rotation are derived analytically. The generally formulated constraints are applied to an isocentric normal-conducting gantry transporting the beams with maximum beam rigidity of 6.6 Tm (e.g. 430 MeV/u carbon beam with a penetration range of 30 cm in water). The gantry is equipped with a two-direction magnetic raster scanning system. The ion-optical properties of the gantry are illustrated by computer simulations performed by the TRANSPORT code.

Oblique gantry — an alternative solution for a beam delivery system for heavy-ion cancer therapy

Beams of protons and heavy ions have favorable physical and biological properties for their application in radiotherapy. Their advantages can be best exploited if the beam can be applied to the patient from any direction by a rotating gantry. The construction of a gantry is quite demanding for heavy ions due to the high magnetic rigidity of the therapy beams. In order to reduce the gantry size and weight, a novel gantry concept with an oblique 60° output beam is proposed. This concept allows a very compact gantry design even for the isocentric layout and normalconducting magnets. The overall gantry radius is 2.8 m. The gantry is equipped with a two-directional magnetic scanning system and an achromatic beam transport system. The scanning system is located upstream to the last gantry dipole and combines a parallel scanning mode in one direction with a low-angle scanning mode in the other direction in order to reduce the vertical gap of the last dipole. The beam transport system is designed with a high degree of ion-optical flexibility which is used to form a narrow pencil-like beam with adjustable spot-size in the gantry isocentre. The design principles and ion-optical properties of the gantry beam transport and scanning systems are discussed.

A new magnetic scanning system for proton microprobe

Design of a new beam scanning system with ferrite-cored magnetic coils is described. Results of testing of the system are presented. Deflecting magnetic field produced by the scanning system shows high degree of uniformity. The fringing fields are decreased sharply along the magnet axis.

The primary test of measuring system for the actual emittance of relativistic electron beams

Abstract Recently, a novel system has been established in Tsinghua University, P.R. China. The system is able to measure the actual phase diagram of a relativistic electron beam (4–10 MeV). The system is mainly composed of a magnetic scanning system, a slit, a fluorescent screen and a CCD camera. After the assembling and testing of the system, as well as the composing of software of the image process, the actual emittance of the 4 MeV electron beam, which is from the standing wave linac in Accelerator Lab, is measured by this system and RMS. Emittance is also achieved. Lastly, the measurement error is analyzed and the overall performance is presented: the system error is 10%–20%, the scope of measurement is 0.4–350 mm mrad. Experiments show that the magnet scanning method is applicable and the system is preliminary practicable.

Magnetic scanning system for heavy ion therapy

Beams of heavy ions have favourable physical and biological properties for the use in radiotherapy. These advantages are most pronoucced if the beam is delivered in a tumor-conform way by active beam scanning. A magnetic scanning technique is used to spread the beam laterally. The range of the particles in tissue is controlled by the variation of the beam energy in the accelerator. Computer simulations were used to compare a discrete scan mode (pixel scan) with a continous scan mode (raster scan). It was found that both methods lead to nearly identical results. The design and technical realization of the magnetic scanning system at GSI combines features of both scan techniques. First results using the lateral beam scanning method as well as the combination of the active energy variation with the magnetic beam scanning are presented.

Performance of a new high current implanter for ion hardening

A new 200 keV high current implanter has been manufactured. The implanter contains a ‘CHORDIS’ ion source, which is capable of producing high current beams of most elements. The implanter is designed for 5–10 mA beam current and has a flexible beam shaping system consisting of a magnetic beam scanning system. The target chamber contains a water cooled sample manipulator with three remote controlled movements. The maximum implant area is 40 × 40 cm 2.

Developments on the Melbourne scanning proton microprobe

An extensive programme of developments on the scanning proton microprobe in Melbourne is described. These developments involve new designs of the specimen chamber, magnetic quadrupole lenses, scanning system and data collection system, extension of the data analysis and handling system and the development of a new overall control system.

A semi-empirical model for the generation of dose distributions produced by a scanning electron beam

There are linear accelerators (Sagittaire and Saturne accelerators produced by Compagnie Generale de Radioiogie (CGR/MeV) Corporation) which produce broad, flat electron fields by magnetically scanning the relatively narrow electron beam as it emerges from the accelerator vaccum system. A semi-empirical model, which mimics the scanning action of this type of accelerator, was developed for the generation of dose distributions in homogeneous media. The model employs the dose distributions of the scanning electron beams. These were measured with photographic film in a polystyrene phantom by turning of the magnetic scanning system. The mean deviation of calculated from measured dose distributions is about 0.2 % , a few points have deviations as large as 2–4 % inside of the 50 % isodose curve, but less than 8 % outside of the 50 % isodose curve. The model has been used to generate the electron beam library required by a modified version of a commercially-available computerized treatment-planning system. (The RAD-8 treatment planning system was purchased from the Digital Equipment Corporation. It is currently available from Electronic Music Industries (EMI), Ltd.)