Conceptual design of a 714-MHz RFQ for compact proton injectors and development of a new tuning algorithm on its aluminium prototype

Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator facilities.An RFQ with a high frequency of 714 MHz dedicated to compact proton injectors for medi-cal applications is designed in this study.The RFQ is designed to accelerate proton beams from 50 keV to 4 MeV within a short length of 2 m and can be matched closely with the downstream drift tube linac to capture more particles through a preliminary optimization.To develop an advanced RFQ,challenging techniques,including fabrication and tuning method,must be evaluated and verified using a prototype.An aluminium prototype is derived from the conceptual design of the RFQ and then redesigned to confirm the radio frequency performance,fabrication procedure,and feasibility of the tuning algorithm.Eventually,a new tuning algorithm based on the response matrix and least-squares method is developed,which yields favorable results based on the prototype,i.e.,the errors of the dipole and quadrupole components reduced to a low level after several tuning iterations.Benefiting from the conceptual design and techniques obtained from the prototype,the formal mechanical design of the 2-m RFQ is ready for the next manufacturing step.

MEVATRON直线加速器INJECTOR故障检修两例

1故障现象 加速器在照光中,发现剂量率突然非常低,出现"Dose rate(sw)"和"Dose rate(hw)"联锁,并且不受调,直至不能出束.

Experimental study of a heavy fuel oil atomization by pressure-swirl injector in the application of entrained flow gasifier

The available SMD(Sauter mean diameter) correlations on pressure-swirl injectors predict droplet sizing very different from each other, especially for heavy fuels. Also there was a lack in the literature for comparing available correlations. So an experimental study was conducted on a heavy fuel oil(HFO) spray, Mazut 380. A pressure swirl injector was designed and fabricated. The experiments for Mazut at 40℃ and 80℃ were compared with the results for water, including spray half cone angle, breakup length and mean droplet diameter,at different injection pressures. Lower spray angle, higher breakup length and larger droplets were observed for lower injection pressures and higher liquid viscosity. SMD was about 75 μm for water and about 87 μm for Mazut at 80℃. The results for droplet mean diameter were also compared with correlations from previous studies on pressure swirl atomizers. The SMD results show that for water spray, LISA method was in good agreement,also Babu and Ballester correlations were successful when high viscosity fluid was injected.

RF design and study of a 325 MHz 7 Me V APF IH-DTL for an injector of a proton medical accelerator

A compact interdigital H-mode drift-tube linac (IH-DTL) with the alternating-phase-focusing (APF) method, working at 325 MHz was designed for an injector of a proton medical accelerator. When fed in with a proper RF (radio frequency) power, the DTL cavity could establish the corresponding electromagnetic field to accelerate the ‘‘proton bunches’’ from an input energy of 3 MeV to an output energy of 7 MeV successfully, without any additional radial focusing elements. The gap-voltage distribution which was obtained from the CST■ Microwave Studio software simulations of the axial electric field was compared with that from the beam dynamics, and the errors met the requirements within ± 5%. In this paper, the RF design procedure and key results of the APF IH-DTL, which include the main RF characteristics of the cavity, frequency sensitivities of the tuners, and coupling factor of the RF power input coupler are presented.

A Laboratory Investigation into the Fuel Atomization Process in a Diesel Engine for Different Configurations of the Injector Nozzles and Flow Conditions

This paper reports a laboratory investigation of the fuel injection process in a diesel engine.The atomization process of the considered fuel(a hydrocarbon liquid)and the ensuing mixing with air is studied experimentally under high-pressure conditions.Different types of injector nozzles are examined,including(two)new configurations,which are compared in terms of performances to a standard injector manufactured by the Bosch company.For the two alternate configurations,the intake edges of one atomizing hole(hole No.1)are located in the sack volume while for the other(hole No.2)they are located on the locking cone of the needle valve.The injection process,the fuel atomization fineness and fuel supply speed characteristics are studied as functions of high-pressure fuel pump camshaft speed and rotation angle.The results obtained show that a decrease in the high-pressure fuel pump camshaft speed can produce fuel redistribution depending on the injector operation.In general,however,the hole No.1 can ensure fuel flow with higher speed with respect to the hole No.2 for all the operation modes of the injector.Based on such an analysis,we conclude that the use of certain injectors can enable a fine tuning of the propagation process of fuel sprays into various areas of the diesel engine combustion chamber.

Influence of eddy current on transient characteristics of common rail injector solenoid valve

Influence of eddy current on transient characteristics of common rail injector solenoid valve was studied in this paper. Experimental investigations of drive current and power source voltage of both drive current ascending and descending process were conducted on a common rail injector solenoid valve. A new discretizing calculation method of solenoid valve flux linkage was put forward for the first time based on the experimental results and drive circuit principle,and flux linkage of both drive current ascending and descending process were evaluated.New inductance calculation methods for drive current ascending and descending process respectively were also presented. Influence of parasitic inductance was evaluated. Results indicate that the air gap,under which the transient flux linkage of the solenoid valve is the biggest,varies with drive current due to eddy current.Flux linkage of drive current descending process is bigger than that of drive current ascending process under the same drive current and the same air gap width. Eddy current can reduce the delay between the time that drive current begins to descend and the time that armature begins to move downward. Inductance of drive current descending process is bigger than that of drive current ascending process over larger scope of drive current,but the difference becomes smaller with the increasing of air gap width. The differences of both flux linkage and inductance between drive current ascending and descending process are caused by the eddy current in core and armature materials.

Numerical simulation of heavy fuel oil atomization using a pulsed pressure-swirl injector

It is known that increasing the injection pressure reduces the breakup length and the droplet size.Adding pulses,on the other hand,helps to atomize the liquid into finer droplets,similar to airassisted injectors but without altering the airtofuel concentration.To further reduce the droplet size and breakup length,a novel injector type,called''Pulsed PressureSwirl"(PPS),is introduced in this work,which is a combination of pressureswirl and ultrasonic pulsed injectors.A pressureswirl atomizer was designed and fabricated specifically for Mazut HFO(Heavy Fuel Oil).The droplet formation process and droplet size distribution have been studied experimentally(by shadowgraphy high speed imaging)and numerically(with the opensource VolumeofFluid code Gerris).Changing liquid injection pressure effect on the spray angle and film thickness has been quantified.These simulations have been used to study the primary breakup process and quantify the droplet size distributions,using different injection pulse frequencies and pressures.The numerical results have revealed that the new injector concept successfully produces finer droplets and results in a decrease in the breakup length,especially when applying high pulse frequencies,with no significant changes in the spray angle.

DEVELOPMENT OF PT PUMP AND INJECTOR TEST STANDS FOR CUMMINS ENGINE

The typc PT—821 PT Pump test stand and typePT—881 injeetor test stand are a set ofspecial test stands for calibration of PT Pumps and injeetors of Cummins engines.Both test standsmay be used in conjunction with any model of Bosch injection pump test benches for PT Pumps andinjector calibration.During PT Pump calibration,the type PT-821 test stand should be used in con-junction with a Boseh injeetion pump test bench.The PT Pump to be tested is installed on Boschinjeetion pump test bench through a mounting bracket and is driven by the bench shaft.When cali-braling PT injeetors,both the PT-881injector test stand and the PT--821 PT Pump test stand shouldbe used in conjunction with a Bosch injection pump test bench with the PT--881 injeetor test stand in-stalled on Bosch lest bench.The injector to be tested is driven by the Bosech injection pump test benchthough a coupling.This paper descrubes the structure and function of the PT--821 PT Pump teststand and PT--881 ubhector test stand.Some technical

Achievement of 1000 s plasma generation of RF source for neutral beam injector

A radio frequency(RF) ion source was developed for neutral beam injector in Institute of Plasma Physics, Chinese Academy of Sciences(ASIPP). A cylindrical driver based RF plasma source was tested and optimized for long pulse operation. Recently, the plasma source achieved 1000 s stable plasma discharge with RF power of 35 k W and source pressure of 0.7 Pa for the first time.The heat loading on each of driver components such as the Faraday shield(FS), RF coil and expansion chamber was measured by the water flow calorimeter system. The experiment results showed that FS is the component with highest heat loading and the heat loading on FS was about 65.8% of total heat loading on source. The details of the long pulse operation of RF plasma source are presented in this paper.

Thermal analysis of EAST neutral beam injectors for long-pulse beam operation

Two sets of neutral beam injectors(NBI-1 and NBI-2) have been mounted on the EAST tokamak since 2014. NBI-1 and NBI-2 are co-direction and counter-direction, respectively. As with indepth physics and engineering study of EAST, the ability of long pulse beam injection should be required in the NBI system. For NBIs, the most important and difficult thing that should be overcome is heat removal capacity of heat loaded components for long-pulse beam extraction. In this article, the thermal state of the components of EAST NBI is investigated using water flow calorimetry and thermocouple temperatures. Results show that(1) operation parameters have an obvious influence on the heat deposited on the inner components of the beamline,(2) a suitable operation parameter can decrease the heat loading effectively and obtain longer beam pulse length, and(3) under the cooling water pressure of 0.25 MPa, the predicted maximum beam pulse length will be up to 260 s with 50 keV beam energy by a duty factor of 0.5. The results present that, in this regard, the EAST NBI-1 system has the ability of long-pulse beam injection.

Discharge Characteristics of Large-Area High-Power RF Ion Source for Positive and Negative Neutral Beam Injectors

A large-area high-power radio-frequency(RF) driven ion source was developed for positive and negative neutral beam injectors at the Korea Atomic Energy Research Institute(KAERI). The RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of high-power RF discharge. Plasma ignition of the ion source is initiated by the injection of argongas without a starter-filament heating, and the argon-gas is then slowly exchanged by the injection of hydrogen-gas to produce pure hydrogen plasmas. The uniformities of the plasma parameter,such as a plasma density and an electron temperature, are measured at the lowest area of the driver region using two RF-compensated electrostatic probes along the direction of the shortand long-dimensions of the driver region. The plasma parameters will be compared with those obtained at the lowest area of the expansion bucket to analyze the plasma expansion properties from the driver region to the expansion region.

SIMULATION OF MICROWAVE GUN INJECTOR RF LINAC DRIVING INFRARED FREE ELECTRON LASERS

In contrast with the conventional injector consisting of dc gun, chopper, subharmonicbuncher and/or fundamental buncher, a microwave gun can cooperate with an alpha magnet as amore compact high brightness injector for the dedicated rf linear accelerators driving infrared freeelectron lasers (FELs). Such a concept has been put into practice in the MARK III FEL and willbe used in the Beijing Free Electron Laser (BFEL) as well. In this paper, the phase spread, energyspread, energy spread, emittance growth and intensity variation of a single electron microbunchin such an FEL accelerator system are investigated using SUPERFISH and PARMELA.

Spray Characteristics of Air-Assisted Injector Under Different Ambient Pressures

Spray atomization of liquid fuel plays an important role in droplet evaporation,combustible mixture formation and subsequent combustion process.Well-atomized liquid spray contributes to high fuel efficiency and low pollutant emissions.Gasoline direct injection(GDI)has been recognized as one of the most effective ways to improve fuel atomization.As a special direct injection method,the air-assisted direct injection utilizes high-speed flow of high-pressure air at the injector exit to assist liquid fuel injection and promote spray atomization at a low injection pressure.This injection method has excellent application potential and advantages for high performance and lightweight engines.In this study,the hollow cone spray emerging from an air-assisted injector was studied in a constant volume chamber with the ambient pressures ranging from 5 kPa to 300 kPa.External macro characteristics of spray were obtained using high speed backlit imaging.Phase Doppler particle analyzer(PDPA)was utilized to study the microcosmic spray characteristics.The results show that under the flash boiling condition,the spray will generate a strong flash boiling point which causes the cone shape spray to expand both inwards and outwards.The axisymmetric inward expansion would converge together and form a lathy aggregation area below the nozzle and the axisymmetric outward expansion greatly increases the spray width.The sauter mean diameter(SMD)of flash boiling condition can be reduced to 5μm compared to the level close to 10μm in the non-flash boiling condition.

Injector of the Turkish light source facility TURKAY

A synchrotron radiation source called TURKAY is proposed as a sub-project of the Turkish Accelerator Center Project. The storage ring of TURKAY is a low emittance synchrotron and the radiation ranges between 0.01 and 60 keV can be generated from the insertion devices and bending magnets placed on it. The injector system of the facility will mainly consist of a 150 MeV linac and full energy booster. In this study, we present design considerations and beam dynamics studies of the pre-injector linac and booster ring for TURKAY.

Control System of Pellet Injector on the HT-7 Tokamak

In this paper the control system of the pellet injector is introduced in detail and the system mainly includes two parts: the present and the remote control system. The present control system controls the injector and provides the interface to the remote system. And the remote control system has acquired present signals with analog input card and perform the actions through digit output card, it also has an interface for Windows programming easily used by the operators when carrying out the pellet injection experiments. Through several HT-7 campaigns, the remote control system has been validated to be feasible and reliable and has made successful shots for studying the interactions between the pellets and plasma.

Fault Detection of Fuel Injectors Based on One-Class Classifiers

Fuel injectors are considered as an important component of combustion engines. Operational weakness can possibly lead to the complete machine malfunction, decreasing reliability and leading to loss of production. To overcome these circumstances, various condition monitoring techniques can be applied. The application of acoustic signals is common in the field of fault diagnosis of rotating machinery. Advanced signal processing is utilized for the construction of features that are specialized in detecting fuel injector faults. A performance comparison between novelty detection algorithms in the form of one-class classifiers is presented. The one-class classifiers that were tested included One-Class Support Vector Machine (OCSVM) and One-Class Self Organizing Map (OCSOM). The acoustic signals of fuel injectors in different operational conditions were processed for feature extraction. Features from all the signals were used as input to the one-class classifiers. The one-class classifiers were trained only with healthy fuel injector conditions and compared with new experimental data which belonged to different operational conditions that were not included in the training set so as to contribute to generalization. The results present the effectiveness of one-class classifiers for detecting faults in fuel injectors.

Evaluation of the Effectiveness of Preloaded IOL Injectors in Surgical Time

Background: The implantation of the intraocular lens (IOL) is still subject to error and complication, as it can result in traumatic opening of the IOL leading to rupture of the posterior capsule and zonular dialysis, it takes time to train paramedic teams to assemble such IOLs with the manual injectors. Moreover, there is a potential risk of comtamination and endophthalmitis as there is manipulation of the IOL and cartridge. The preloaded IOLs tend to reduce those unwanted results and may optimize the surgical time. Purpose: The aim of this study is to compare the effectiveness and implantation time between three injectors and three intraocular lenses, two pre-loaded and one conventional. Methodology: Videos of thirty patients undergoing cataract surgery from December 2019 to December 2020 at the Hospital Oftalmológico de Brasília (HOB), Brasília, Brazil were included in this observational, analytical retrospective study, non randomized. All patients had their surgeries recorded, from which the time of injection and opening of the intraocular lens (IOL) was extracted, 20 eyes were implanted with preloaded intraocular lens, and 10 eyes with conventional IOL implant. The patients were divided into three groups with similar eye characteristics. The first received the AutonoMeTM (CE) injector with the Clareon® IOL, the second the IsertTM injector (I) with the Hoya® IOL, and the third was injected with Johnson & Johnson Platinum 1 Series injector used to deliver Sensar® One AAB00 lens. The Welch test and Tukey’s Post Hoc test were used in the statistical analysis. Results: It was observed that there was a statistical significance regarding the presence of a haptic stuck (5 Clareon vs 0 Sensar and Hoya), between the mean opening time of the IOL optics Sensar One, Hoya and Clareon (25.00 vs 31.40 vs 11.70 s, p < 0.001) and between the total time (the injection time more the opening time of the IOL) in relation to Hoya and Clareon lenses (39.50 s vs 19.60 s, p < 0.001);the total time of the Sensar IOL was 31.30 s. The opening time of the IOL optics was significantly longer for the Sensar One and Hoya groups compared to Clareon group, and the total time of Hoya group was significantly longer compared to the total time of the Clareon group. Conclusion: The study demonstrated that the choice of injector and IOL set can significantly affect the total time of IOL implantation. However, there was no difference regarding complications and collateral damage depending on the set chosen for the implant.

6-9 CW Beam Test of the Injector II RFQ for ADS Project

As one of the main components of the injector II of China ADS LINAC project, an RFQ working at 162.5 MHzis used to accelerate proton beams of 15 mA from 30 keV to 2.1 MeV. The four vane RFQ has been designed incollaboration with Lawrence Berkeley National Laboratory and built at the workshop of the Institute of ModernPhysics, Chinese Academy of Sciences (IMP, CAS).

6-2 Progress of the IH-DTL Accelerator for HIRFL Injector

As a powerful heavy ion injector for HIRFL, the SSC-Linac is under constructing at IMP. In 2015, the manu-facture of the rst IH-DTL cavity has been nished. Low power measurement and high power conditioning were performed in sequencely. The recent R&D progress of the SSC-Linac and the development of IH-DTL accelerator are presented.