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We implemented a method to tune the ESS superconducting cavities based on the spectral analysis of the high resolution data available from the Low Level RF system (LLRF) for the transmitted power, without the need of connecting a network analyzer or any other dedicated instrumentation along the RF chain. A frequency peak up to 4 MHz off from the resonating frequency can be detected and used to control the stepper motor of the tuner until the cavity is stretched to the proper length to reach the correct operation frequency. Experience of its use at the ESS Test Stand 2 (TS2) facility at Lund during cryomodule acceptance testing is presented.

Background and aimsThe effect of surgical treatment for spontaneous intracerebral hemorrhage (ICH) remains uncertain. We conducted an observational retrospective cohort study on supra-centimeter spontaneous ICH treated with either neurosurgical or conservative management. The baseline demographics and risk factors were correlated with in-hospital mortality and 3 and 6-month survival rates stratified by management.MethodsWe included all patients with evidence of spontaneous ICH > 1 cm detected by CT and admitted between august 2020 and march 2021 to the “SMM” Hospital in Perugia.ResultsOnehundredandtwentytwo patients were included in the study, and 45% (n.55) were surgically treated. The mean age was 71.9 ± 15.3, and 61% (n.75) were males. Intra-hospital mortality ended up being 31% (n.38), 3 months-survival was 63% (n.77) and 6 months-survival was 60% (n.73).From the multivariate analysis of the surgical patients versus medical patient, we observed that the surgical patients were younger (67.5 ± 14.9 vs 75.5 ± 14.7 y; OR 0.87; Cl 95% 0.85–0.94; p 0.001), with greater ICH volume at the onset (61 ± 39.4 cc vs 51 ± 64 cc; OR 1.03; Cl 95% 1.005–1.07; p 0.05), more midline shift (7.61 ± 5.54 mm vs 4.09 ± 5.88 mm; OR 1.37; Cl 95% 1.045–1.79; p 0.023), and a higher ICH score (3 vs 2 mean ICH score; OR 21.12; Cl 95% 2.6–170.6; p 0.004). Intra-hospital mortality in the surgical group and in the conservative treatment group was respectively 33% vs 30%, 3 month-survival was 64% vs 63% and 6 month- survival were 60% in both groups.ConclusionsOur patient cohort shows no overall benefit from surgery over conservative treatment, but surgical patients were younger and had larger ICH volume.

We report the experience of the production, processing and qualification testing of the superconducting radio frequency cavities at 3.9 GHz for the third harmonic system at the European XFEL (EXFEL) injector. The rf structure concept, originally developed for the FLASH FEL facility, was adapted to the new interfaces provided by the EXFEL design and the cavities were procured from a qualified vendor, delivered ready for the testing at the INFN infrastructure. A total of 23 cavities, three prototypes and two batches of 10, have been realized and tested up to specifications.

System performance is a key factor to take into account throughout the software life cycle of modern computer systems, mostly due to their typical characteristics such as distributed deployment, code mobility, and platform heterogeneity. An open challenge in this direction is to integrate the performance validation as a transparent and efficient activity in the system development process. Several methodologies have been proposed to automate the transformation of software/hardware models into performance models. In this paper, we do not take a transformational approach; rather, we present a framework to integrate a software model with a platform model in order to build a performance model. Performance indices are obtained from simulation of the resulting performance model. Our framework provides a library of predefined resource models, model annotation and integration procedures, and simulation support that makes the performance analysis a much easier activity. We present the results obtained from two different industrial case studies that show the maturity and the stability of our approach

The limits of performance of the European XFEL 3.9 GHz superconducting cavities were investigated. Most cavities exhibited high field Q slope, reaching the breakdown field at approximately22MV/m. We hypothesize that this limit is a feature of high frequency cavities and can be explained by a thermal model incorporating field dependent surface resistance. The results obtained from simulations were in good agreement with experimental data obtained at 2 K.

Cooperative Cyber-Physical Systems (Co-CPSs) can be enabled using wireless communication technologies, which in principle should address reliability and safety challenges. Safety for Co-CPS enabled by wireless communication technologies is a crucial aspect and requires new dedicated design approaches. In this paper, we provide an overview of five Co-CPS use cases, as introduced in our SafeCOP EU project, and analyze their safety design requirements. Next, we provide a comprehensive analysis of the main existing wireless communication technologies giving details about the protocols developed within particular standardization bodies. We also investigate to what extent they address the non-functional requirements in terms of safety, security and real time, in the different application domains of each use case. Finally, we discuss general recommendations about the use of different wireless communication technologies showing their potentials in the selected real-world use cases. The discussion is provided under consideration in the 5G standardization process within 3GPP, whose current efforts are inline to current gaps in wireless communications protocols for Co-CPSs including many future use cases.

A full test of the cavity package concept under realistic operating condition was a necessary step before the assembly of the European XFEL (EXFEL) 3.9 GHz superconducting system and its installation in the accelerator. One cavity, equipped with magnetic shielding, power coupler and frequency tuner has been tested in a specially designed single cavity cryostat in one of the test benches of the DESY Accelerator Module Test Facility (AMTF). The cavity was operated at high pulsed power up to an accelerating field of 24MV/m , above the quench accelerating field of 21MV/m achieved during the continuous wave (CW) vertical qualification test and with a large margin with respect to the EXFEL maximum operating specification of 15MV/m for the 3.9 GHz system. All subsystems under test—coupler, tuner, waveguide tuners, low level radio-frequency (LLRF) system—were qualified to their design performances.

Three 6-cell 805 MHz superconducting cavity prototypes for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light have been fabricated and tested. The quality factors (Q0 ) were between 7×109 and 1.4×1010 at the design field (accelerating gradient of 8–10MV/m ). The maximum gradients reached were between 11 and 16MV/m ; in each case, the Q0 values were ≥3×109 at the maximum gradient. The design, fabrication, surface preparation, and rf testing of the 6-cell cavities are reported in this paper.