New applications of 10 MeV electrons for reeled goods

Because of their high penetration capability, electron beams produced by 10 MeV machines are increasingly used for the sterilization processing of medical devices. Worldwide there are already more than 20 such machines in action for this purpose. But compared with electron beam sterilization, the physical crosslinking of plastic products with 10 MeV has not been as much investigated as in the range of low and medium energy. So the products with high wall thickness or big dimensions are still chemically crosslinked as the penetration and power of the beam of existing accelerators was not sufficient for those products. But now radiation crosslinking is possible also for higher dimensions of reeled goods due to higher beam power up to 150 kW, and one machine with different handling systems can be used for sterilization and modification of plastic products.

The aim of our work is to examine the homogeneous crosslinking of industrial products by a 10 MeV/150 kW electron beam as for instance for XLPE-c pipes and heat shrinkable tubes. Furthermore the uniformity of crosslinking especially along the roundness is measured, which is one of the essential quality characteristics.     

Automated technological radiation installation for sterilization of medical goods

Last years most of the developed countries are using radiation method based on electron accelerators for sterilization of medical goods as mostly safe and ecologically pure from all known methods. The report describes in details the automated installation for sterilization of single-use syringes working in the city of Izhevsk, Russia. The syringes are irradiated from two sides inside the packs containing 250 units each. The packs are automatically turned on the inclined part of the conveyor under influence of their own weight. The syringes are posed vertically along the beam fall. The ration of maximal absorbed dose to minimal is 1.4. The productive rate of installation is no less 100 000 syringes per hour. The installation is based on the linear pulse electron accelerator ILU-6. It is the single cavity machine with electron energy up to 2.5 MeV and average beam power up to 20 kW. The pulse nature of the current and automatic control system permit to vary the absorbed dose in great range. The electron energy, beam current, pulse repetition rate, beam position in the extracted window and transportation of the treated products are computer controlled.     

我院医用数字X射线摄影系统设备质量控制及机房放射防护现状分析

为分析我院医用数字X射线摄影系统(DR)设备质量控制状态及机房放射防护现状,本研究选取截止2019年6月我院安装完毕并已验收检测合格投入使用的5台DR设备作为研究对象,依据WS 521-2017《医用数字X射线摄影(DR)系统质量控制检测规范》的检测要求和技术指标,对DR设备质量控制状态进行评价,根据GBZ 130-2013《医用X射线诊断放射防护要求》的检测要求和技术指标对机房放射防护情况进行评价。质量控制检测结果显示,5台DR设备中有2台DR设备各有1项检测项目不符合国家标准要求,总合格率为60.0%。各项检测指标中,管电压指示的偏离、光野与照射野四边的偏离不合格各有1台,合格率为80.0%;有用线束半值层、输出量重复性、有用线束垂直度偏离、光野与照射野中心、输出量线性、曝光时间指示的偏离合格率均为100.0%。机房放射防护检测结果显示,5台DR设备机房58个检测点的周围剂量当量率检测中有6个检测点发生泄露,泄露发生率为10.3%。结果表明,我院DR设备质量控制检测不合格率较高,DR机房泄漏风险也较高,需加强DR设备的质量控制,完善机房辐射安全管理,以保证影像辅助诊断的质量,以及放射工作人员和公众在放射诊疗过程中免受一切不必要的电离辐射。     

E-Beam—a new transfer system for isolator technology

In every aseptic filling application, the sterile transfer of goods into the aseptic area is a challenge, and there are many different ways to do it.

With isolator technology a higher sterility assurance level (SAL) is achieved. This SAL is only as good as the weakest segment in the chain of manufacturing. The transfer of goods into and out of the isolator is one of these critical segments.

Today different techniques, some already well established, others still very new, are available on the market like: dry heat tunnel, autoclave, pulsed light, rapid transfer systems (RTP), H₂O₂ tunnel, UV light, etc. all these systems are either not applicable for continuous transfer, only good for heat-compatible materials like glass, or do not guarantee a 6 log spore reduction.

E-Beam opens new perspectives in this field. With E-beam technology it is possible to transfer heat-sensitive (plastic), pre-sterilised materials at high speed, continuously into an aseptic area.

E-Beam unifies three different technologies, that result in a very efficient and high-speed decontamination machine designed for the pharmaceutical industry. First, there is the electron beam that decontaminates the goods and an accurate shielding that protects the surrounding from this beam. Second, there is the conveyor system that guarantees the output and the correct exposure time underneath the beam. And third, there is the isolator interface to provide correct differential pressure and clean air inside the tunnel as well as the decontamination of the tunnel with H₂O₂ prior to production.

The E-beam is a low-energy electron beam, capable of decontaminating any kind of surface. It penetrates only a few micrometers into the material and therefore does not deform the packaging media.

Currently, machines are being built to transfer pre-sterilised syringes, packed in plastic tubs with a Tyvek cover into an aseptic filling isolator with the following data: decontamination efficiency of 10⁶ (6 log spore reduction), decontamination speed of 6 tubs (600 syringes) per minute.

This is just one of many applications for this new technology.     

A new irradiation plant in Italy: Technical features and activities performed

Since 1995, a new Hitesys Co. pilot/industrial irradiation plant has been operating in Aprilia, 50 km south of Rome. The plant, which was jointly designed by ENEA and Hitesys Co., is equipped with a highly flexible automatic materials transport system which is also suitable for continuous process repetition or, when upturned, for double-side material treatment. The main features of the irradiation plant are:

• - the radiation source: EB-machine LINAC type (s band) with maximum electron beam energy of 10 MeV and beam power of 1000 W;

• - the bunker: external type, shielded by ordinary concrete, equipped with a suitable entrance/exit maze in order to allow easy handling and managing of materials as well as to facilitate equipment and machinery maintenance and inspection activities.

An intense program of R&D activities and technological services has already been performed in relation to industrial processes and environmental applications, as well as many other radiation technology applications, including agriculture related processes.     

Image reversal for direct electron beam patterning of protein coated surfaces

Electron beam lithography (EBL) is used to create surfaces with protein patterns, which are characterized by immunofluorescence and atomic force microscopies. Both negative and positive image processes are realized by electron beam irradiation of proteins absorbed on a silicon surface, where image reversal is achieved by selectively binding a second species of protein to the electron beam exposed areas on the first protein layer. Biofunctionality at the cellular level was established by culturing cortical cells on patterned lines of fibronectin adsorbed on a bovine serum albumin background for 7 days in culture.     

Re-commissioning of an electron accelerator: industrial-type in research style

After 25 years of utilization in 1992, the electron linear accelerator was replaced by a modern type, CIRCE III of CGR-MeV (now Thomson-CSF). The goal had been to bring a typical industrial-style machine-source of radiation to the research institute in order to enable it to study any relevant parameter in radiation processing of food under commercial conditions. The machine should be as close in design to industrial practices, but at the same time allow for research into dosimetry and process control. As the FRCN moved to its new site, the decision was to re-install the accelerator there. At this occasion and based on the operating experiences of the recent years, several new features were introduced: the scan mode was changed from during-pulse to shot-by-shot; the bending magnet was modified from 107° to 253° (pretzel-type); the exploitable scanning width was increased from 40 to 80 cm. After this modification, the machine characteristics had to be verified. For the changed scan-mode the adjustment of pulse repetition rate, scan frequency, transport velocity, and beam cross-section in both directions, had to be established for the targeted low-dose treatments (about 100 Gy). Furthermore, the facility has now two separated beam-outlets, one for handling the prepacked materials on a transport system, the other one for bulk material handling (not yet installed) and for bremsstrahlung-mode experiments. First results with the accelerator after its transfer to the new site are reported; the radiation field characteristics after the modifications are given.     

Decomposition of PCBs in transformer oil using an electron beam accelerator

Decomposition of PCBs in commercially used transformer oil used for more than 30 years has been carried out at normal temperature and pressure without any additives using an electron beam accelerator. The experiments were carried out in two ways: batch and continuous pilot plant with 1.5 MeV of energy, a 50 mA current, and 75 kW of power in a commercial scale accelerator.The electron beam irradiation seemed to transform large molecular weight compounds into lower ones, but the impact was considered too small on the physical properties of oil. Residual concentrations of PCBs after irradiation depend on the absorption dose of the electron beam energy, but aliphatic chloride compounds were produced at higher doses of irradiation. As the results from FT-NMR, chloride ions decomposed from the PCBs are likely to react with aliphatic hydro carbon compounds rather than existing as free radical ions in the transformer oil. Since this is a dry process, treated oil can be used as cutting oil or machine oil for heavy equipment without any additional treatments.     

Test to evaluate countercurrent chromatographs. Liquid stationary phase retention and chromatographic resolution

Countercurrent chromatography (CCC) is a liquid chromatography (LC) technique with a special column able to retain a liquid stationary phase while the liquid mobile phase is pumped through. The coil planet centrifuge machines are made of open tube wound on spools. A simple test is proposed. The methanol-water (90:10, v/v)-heptane biphasic system is used with heptane as the mobile phase in the ascending or tail-to-head mode. The methanol-water stationary phase retention volume is measured at different flow-rates and rotor rotation speeds. After every machine equilibration, an alkylbenzene mixture is injected and the retention factors, peak efficiencies and resolution factors are measured or calculated for each solute. The wealth of information contained in the data set obtained is demonstrated. Four coil planet centrifuge machines of very different characteristics and one hydrostatic CCC machine with channels and ducts were submitted to the test. It was shown that the Sf, stationary retention factor, obtained with these machines was linearly dependent on the square root of F, the mobile phase flow-rate [Q. Du, C. Wu, G. Qian, P. Wu, Y. Ito, J. Chromatogr. A 835 (1999) 231-235]. It is shown that the slopes of the Sf versus F(1/2) lines could be related to a minimum rotor rotation, omega(mini), necessary to obtain the hydrodynamic equilibrium. The Sf and F parameters give the mobile phase linear velocity, u. It is shown that u is proportional to the square root of omega, the rotor rotation speed. The slope and intercept of the latter relationship also result in an omega(mini) value coherent with the first one. With the peak efficiencies and chromatographic resolution factors obtained for toluene and hexylbenzene, the parameters: number of plates per tubing turn, machine volume for one plate, and tubing length for one plate, were calculated and compared for the five machines. The internal diameter of the tubing used is shown to be a critical parameter acting on the machine volume and number of tubing turns.     

Evaluation of different machines used to quantify genetic modification by real-time PCR

Quantification of genetic modification (GM) is often undertaken to test for compliance with the European Union GM labeling threshold in food. Different control laboratories will often use common validated methods, but with different models of real-time PCR machines. We performed two separate ring trials to evaluate the relative precision and accuracy of different types of real-time PCR machines used to quantify the concentration of GM maize. Both trials used dual-labeled fluorogenic probes for quantification. The first ring trial used separate GM and reference assays (a single fluorescence channel), and the second used a combined duplex assay (two simultaneous fluorescence channels). Five manufacturers and seven models--including a 96-well microtiter-plate, rotary, and portable machines--were examined. In one trial, the machine used had a significant effect on precision, but in the other it did not. Overall, the degree of variation due to the machine model was lower than other factors. No significant repeatable difference in accuracy was observed between machine models. It was not possible to use sufficient replication of machine type in each laboratory to examine all sources of variation in this study, but the results strongly indicate that factors other than machine type or manufacturer (e.g., method or laboratory) contribute more to variation in a GM quantification result.     

Application of statistical methods (SPC) for an optimized control of the irradiation process of high-power semiconductors

High-power bipolar semiconductor devices (thyristors and diodes) in a disc-type shape are key components (semiconductor switches) for high-power electronic systems. These systems are important for the economic design of energy transmission systems, i.e. high-power drive systems, static compensation and high-voltage DC transmission lines. In their factory located in Pretzfeld, Germany, the company, eupec GmbH+Co.KG (eupec), is producing disc-type devices with ceramic encapsulation in the high-end range for the world market. These elements have to fulfil special customer requirements and therefore deliver tailor-made trade-offs between their on-state voltage and dynamic switching behaviour. This task can be achieved by applying a dedicated electron irradiation on the semiconductor pellets, which tunes this trade-off. In this paper, the requirements to the irradiation company Mediscan GmbH, from the point of view of the semiconductor manufacturer, are described. The actual strategy for controlling the irradiation results to fulfil these requirements are presented, together with the choice of relevant parameters from the viewpoint of the irradiation company. The set of process parameters monitored, using statistical process control (SPC) techniques, includes beam current and energy, conveyor speed and irradiation geometry. The results are highlighted and show the successful co-operation in this business. Watching this process vice versa, an idea is presented and discussed to develop the possibilities of a highly sensitive dose detection device by using modified diodes, which could function as accurate yet cheap and easy-to-use detectors as routine dosimeters for irradiation institutes.     

From controlled 3-dimensional architectures to smart materials

Under the pressure of bad economic conditions, Chemical Industry and the Polymer Producing Industry in particular, have been focusing on core businesses and several developments in advanced materials have been slowed down. Increased competition from low cost countries imposes rigorous restructuring of the traditional industry. Environmental considerations enhance the pressure even more. While the Polymer Industry is struggling with major restructuring operations, the scientific activities in the field of macromolecules show a tremendous innovative power. Ever increasing molecular control by the use of new catalysts, cooperative supramolecular interactions and controlled building up of 3-dimensional structures, new architectures leading to enhanced performance and completely new properties, development of functional materials and smart materials are hot items at every meeting. The outcome of this situation could be that the world of materials and materials producers will look quite different in the first decade of the next century.     

Instrumental neutron activation analysis technique using subsecond radionuclides

The fast irradiation facility Mach-1 installed at the Danish DR 3 reactor has been used in boron determinations by means of Instrumental Neutron Activation Analysis using¹²B with 20-ms half-life. The performance characteristics of the system are presented and boron determinations of NBS standard reference materials as well as fertilizer materials are compared by literature value and spectrophotometric measurements, respectively. In both cases good agreement is obtained.     

Technological applications of BINP industrial electron accelerators with focused beam extracted into atmosphere

Simultaneously with production of industrial accelerators BINP develops new EB technologies. For this purpose the set of equipment based on electron accelerators was installed. The accelerator has an energy range of 0.8–1.5 MeV and a maximum electron beam power of 100 kW. Electron beam is extracted into the atmosphere through the system of diaphragms with output holes about 1 mm in diameter. The operational vacuum in the accelerating tube is provided by a differential pumping system. The extraction device is equipped with additional scanning magnets. It allows the operator to change average beam power density in extra wide region from 10 to 10⁷ Wt/cm². The focused beam has many applications due to its unique properties.     

Abiotic Chemical Fuels for the Operation of Molecular Machines

Natural molecular machines require a continuous fuel supply to perform motions and/or remain in a functional state. Consequently, the aim of developing artificial devices and materials with life‐type properties has motivated a growing interest in abiotic chemical fuels and in their supply modalities. Many artificial molecular machines have been developed in which the sequential addition of several chemical reagents allows the machine to perform complete cycles of motion. Only recently, examples of molecular machines whose cycles of motion are triggered by a single pulse of fuel have been reported. The latter systems are the object of this Minireview where the abiotic chemical fuels used so far to trigger the complete cycles of motion of molecular machines are described, with particular emphasis on the operation mechanism of the machine/fuel systems.     

Experimental assessment of stiffness and energy dissipation properties of disk-shaped polymer-based composite specimens by in-plane torsion testing

Torsion testing machines are widely used either to measure the strength, stiffness and stress-strain properties of materials or to replicate real-life service conditions. In this paper, a novel experimental method is presented, based on the development of a dedicated steel structure to be used in conjunction with a universal testing machine. This equipment allows applying cyclic in-plane torsion loads on disk-shaped components. The proposed approach aims to enable the assessment of stiffness and damping properties on specimens enabling the application of higher loads in comparison with the traditional machines.Specifically, dynamic trials were performed by attaching the composite specimens and the steel structure to the testing machine, such that the uniaxial controlled displacements can be used to exert the desired cyclic loads onto the specimen. Both torsional stiffness and energy loss were measured from the steady-state load-displacement hysteresis cycles. Amplitudes of sine signals, from 0.05 to 0.2 mm, and a frequency ranging between 1 and 20 Hz, were used in the experiments. The results are presented comparing the behaviour of two polymer matrix composites, with the same number of identical laminae, but characterized by different stacking sequences, namely unidirectional and quasi-isotropic configurations.     

Best use of high-voltage, high-powered electron beams: a new approach to contract irradiation services

Japan’s first high-voltage, high-powered electron beam processing center is scheduled to come on-line during the first half of 1999. The center explores both challenges and opportunities of how best to use the 200 kW 10 MeV unit and its 5 MeV X-ray line. In particular, Nuclear Fuel Industries, Ltd. (NFI) has expanded the traditional model of a contract irradiation facility to include a much broader scope of services such as door-to-door transport, storage, and direct distribution to its customer’s end-users. The new business scope not only finds new value-added components in a competitive marketplace, but serves to provide a viable mechanism to take advantage of the processing logistics of high throughput irradiation units. As such, the center features a high-capacity warehousing system, monitored by a newly developed PCMS (plant control management system), which has been comprehensively integrated into the irradiation unit’s handling system, and will require only minimal human resources for its high rate of material handling. The identification and development of initial markets for this first unit will be discussed, concluding with how this same operational philosophy can help break open new irradiation segments in medical devices, consumer goods, animal feed, and food markets and NFI’s other efforts in these same areas.     

Upgrade of the prompt gamma activation analysis and the neutron-induced prompt gamma spectroscopy facilities at the Budapest research reactor

The Budapest Research Reactor’s Prompt Gamma Activation Analysis (PGAA) and Neutron-Induced Prompt gamma Spectroscopy (NIPS) facilities were significantly upgraded during the last few years. The higher neutron flux, achieved by the partial replacement and realignment of the neutron guides, made feasible the automation and specialization of the two experimental stations. A new neutron flux monitor, computer-controlled beam shutters and a low-level counting chamber have been put into operation to assist with in-beam activation experiments. An automatic sample changer has been installed at the PGAA station, while the NIPS station was redesigned and upgraded with a Compton suppressor to use for the non-destructive analysis of bulky samples. In the near future the latter setup will be completed with a neutron tomograph and a moving table, to turn it into a Neutron Radiography/Tomography-driven PGAA equipment.     

On the role of parallel architecture supercomputers in time-dependent approaches to quantum scattering

Summary Results of our initial study of the use of parallel architecture super-computers in solving time-dependent quantum scattering equations are reported. The specific equations solved are obtained from the time-dependent Lippmann-Schwinger integral equation by means of a quadrature approximation to the time integral. This leads to a modified Cayley transform algorithm in which the primary computational step is a matrix-vector multiplication. Implementation has been carried out both for the MasPar MP-1 and the NCUBE 6400 parallel machines. The codes are written in a modular form that greatly facilitates porting from one machine architecture to another. Both parallel machines prove to be more powerful for this application than the serial architecture VAX 8650. Specific analysis of machine performance is given.Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. 2-7405-ENG-82. This research was supported by the Division of Chemical Sciences and Applied Mathematical Sciences, Office of Basic Energy SciencesR.A. Welch Predoctoral Fellow under R.A. Welch Foundation Grant E-608Supported in part under National Science Foundation Grant CHE89-07429