Ultrasonic NDE testing of a gradient enhanced piezoelectric actuator (GEPAC) undergoing low frequency bending excitation

Gradient Enhanced Piezoelectric Actuators (GEPAC) are thin piezoelectric plates embedded between two composites layers having different thermal properties. Compared to standard unimorph bending actuators, GEPACs offer superior performances for operations at low frequencies. Potential applications are in the area of multifunctional aircraft skins. In practice, delaminations or debonding within the actuator itself can occur, and it is highly desirable to develop an ultrasonic nondestructive method to monitor the integrity of the actuator in real time. For this study, the composite material is unidirectional Kevlar-epoxy, with fibers oriented at 90 and 0 for the upper and lower layers to achieve different coefficient of thermal expansion. A thin PZT plate is inserted between the two layers, and extended copper foil is used for electrodes on the PZT. The first objective of the research is to demonstrate that, by using segmented electrodes, one can simultaneously launch an ultrasonic pulse (1 MHz) for NDE testing while the actuator is undergoing low frequency actuation (less than 100 Hz). The second objective is to show that the ultrasonic signal can be used to detect damage induced during fatigue testing of the actuator. The third objective is to use the technique to monitor the integrity of a composite plate containing several embedded GEPACs.M.S.Committee Chair: Berthelot; Committee Member: Jacobs; Committee Member: Lync

Status of the RFQ linac installation and conditioning of the Linear IFMIF Prototype Accelerator

Abstract The Radio Frequency Quadrupole (RFQ) linac and 1.6 MW RF power system of the Linear IFMIF Prototype Accelerator (LIPAc) facility in the International Fusion Energy Research Center (IFERC) in Rokkasho (Japan) has been installed and conditioned. During the assembly and tuning process, the RFQ cavity was protected with a temporary tent from the potential deterioration of performance caused by dust. The vacuum in the cavity was improved through the 100 °C baking process of the cavity. The high power test of the 175 MHz RF systems up to 200 kW in CW for each of the eight RF chains was performed for checking its stable output reproducibility in Japan, before connecting 9–3/16 inch coaxial transmission lines from the RF chains to the RF input couplers of the cavity. It was confirmed that the eight RF chains provided the balanced RF power to the single RFQ cavity in-phase using a feedback loop and a synchronization system. The peak power in the cavity achieved 150 kW in the pulsed mode, which corresponds approximately to the required electric field to accelerate proton beam. Such RF conditioning process is ongoing to achieve 600 kW approximately required for deuteron beam commissioning planned in 2018

Radiation safety study for the beam commissioning of IFMIF/EVEDA LIPAc RFQ in Rokkasho

The construction of the Linear IFMIF Prototype Accelerator (LIPAc) is in progress at Rokkasho, Japan. The important milestone of the project is to commission the necessary components, namely RFQ, MEBT and diagnostics, to accelerate the proton beam up to 2.5 MeV or the deuteron beam up to 5.0 MeV in pulsed mode with a low duty cycle of 0.1%. The detailed radiation safety analysis has been conducted for the beam commissioning with the consideration of the specific radiation source conditions and the building configuration. As a result, it turned out that the dose rate expected outside the accelerator vault during deuteron beam operation at 5 MeV is mostly dominated by the neutron streaming effect through three major penetration sectors, i.e. HVAC ducts, water pipe holes and underground pits, while it is negligibly small during the proton beam operation at 2.5 MeV. It was confirmed that the dose rate expected does not exceed the legal limit for the controlled area boundary and no serious radiological issues exist in the beam commissioning planned

Metachronous lung cancer resection on extracorporeal membrane oxygenation in a pneumonectomized and mediastinum irradiated patient

The management of localized, metachronous, primary non-small cell lung cancer (MP-NSCLC) in pneumonectomized patients is challenging. It generally consists in stereotactic radiation therapy. We report the case of a 57-year-old patient who had a prior history of left pneumonectomy and mediastinal irradiation to manage a central stage IIIA NSCLC. He developed a MP-NSCLC in the middle lobe after 6 years. Stereotactic radiation was judged too risky because of the cumulative dose to the heart and risk of pneumonitis. Pulmonary functions and the cardiovascular evaluation were normal. Multidisciplinary discussions suggested a local treatment for this lesion. The patient underwent a thoracoscopic middle lobe lateral segmentectomy on veno-venous extracorporeal membrane oxygenation (VV-ECMO) support. The patient was extubated and weaned from the ECMO at the end of the case and stayed 24 h at the intensive care unit for surveillance. He was discharged from the hospital on day 4. The histopathological analysis revealed a moderately differentiated NSCLC that was completely resected with no lymph node invasion (pT1N0L0V0Pn0R0). Twenty-four months after surgery, the patient is alive and disease free. Management of MP-NSCLC in pneumonectomized patients is challenging and should be tailored to each individual case. Extracorporeal life support has helped push the boundaries of patient operability thus extending survival for patients that could previously not be considered for surgery

Radiation shielding requirements for the full power operation of the linear IFMIF prototype accelerator (LIPAc) at Rokkasho

The detailed shielding analysis has been performed in order to find a configuration of the radiation shielding in the accelerator building necessary for the operation of the Linear IFMIF Prototype Accelerator (LIPAc), which is under construction in Rokkasho, Japan, at the full power of 1.125 MW to satisfy the radiation dose limit prescribed by Japanese regulations. The final design of the beam dump constructed by CIEMAT, Spain was fully taken into consideration. The impact of all the features potentially causing neutron streaming were investigated and the optimization of local additional shieldings were conducted. As the result, the most important one was found to be the air ventilation duct shield, which completely covers the ducts and creates an additional labyrinth. By considering the additional shielding configuration determined in the present study, the legal criteria at the controlled area boundary can be completely satisfied

Operational Consideration in the LIPAc SRF with Potential Solenoid Failure Modes

International audienceThe commissioning of LIPAc (Linear IFMIF Prototype Accelerator) is ongoing at Rokkasho institute of QST for the engineering validation of the accelerator system up to 9 MeV/125 mA. Several SRF cryomodules will be required for IFMIF to accelerate deuterons from 5 MeV to 40 MeV. The prototype of the first of these cryomodules has been manufactured and will be installed and tested on the LIPAc. It holds the eight HWRs (Half Wave Resonator) and RF couplers to accelerate the beam and the eight superconducting solenoids to focus it. During the solenoid HPR process, carried out after fixing welding issues on the solenoid beam line bellows, some concerns appeared about the integrity of two solenoids. The examination with CT scanning of the solenoids revealed that one screw and a few pins had leaved their socket. Although it should be no critical problem, we tried the beam simulation with PIC code TraceWin to determine the location of solenoids whose impact will be minimized to manage in case of failure of solenoid as mitigation action. This paper presents the recommended locations of the suspicious solenoids in the cryomodule and resultant beam conditions through the beam dynamics study

Measurements of Momentum Halo Due to the Reduced RFQ Voltage During the LIPAc Beam Commissioning

International audienceThe Linear IFMIF Prototype Accelerator, LIPAc, is being commissioned aiming in particular at validating the RFQ up to 5MeV beam acceleration. Eventually, the nominal beam of 5 MeV-125 mA in 1 ms/1 Hz pulsed mode was achieved in 2019. The beam operation has been resumed since July 2023 after long maintenance including recovery from unexpected problems in the RFQ RF system. This new phase aims at the commissioning of the full configuration except SRF linac, which is replaced by a temporary beam transport line. Focusing on the RFQ behavior, it will be interesting to operate it at higher duty especially for longer pulses. Indeed, a beam simulation study suggested that the beam extracted from the RFQ includes considerable momentum halo when the RFQ voltage reduces by a few percent, with a slight decrease of mean energy. It can be a potential source of quench like the mismatched beam in the cryomodule. This could be studied measuring the energy from the Time-of-Flight among multiple BPMs while monitoring beam loss around the dipole, where momentum halo should be lost. During the upcoming commissioning, we propose to study them by scanning the RFQ voltage