Investigations on Caesium Dispersion and Molybdenum Coating on SPIDER Components.

SPIDER is the 100 keV full-size Negative Ion Source prototype of the ITER Neutral Beam Injector, operating at Consorzio RFX in Padova, Italy. The largest Negative Ion Source in the world, SPIDER generates an RF driven plasma from which Deuterium or Hydrogen negative ions are produced and extracted. At the end of 2021, a scheduled long-term shutdown started to introduce major modifications and improvements aiming to solve issues and drawbacks identified during the first three years of SPIDER operations. The first action of the shutdown period was the disassembly and characterization of the SPIDER beam source after removal from the vacuum vessel and its placement inside the clean room. Each component was carefully assessed and catalogued, following a documented procedure. Some source components, i.e., the Plasma Grid, Extraction Grid and Bias Plate, revealed the presence of different and non-uniform red, white and green coatings that might be correlated to back-streaming positive ions impinging on grid surfaces, electrical discharges and caesium evaporation. Thus, several analyses have been carried out to understand the nature of such coatings, with the study still ongoing. The evidence of caesium evaporation and deposition on molybdenum-coated SPIDER components, such as the formation of oxides and hydroxides, is demonstrated through surface characterization analyses with the use of the Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS).

Risk factors for postoperative eye pain in patients with non-painful eye disease undergoing pars plana vitrectomy: the VItrectomy Pain (VIP) study.

BACKGROUND: Pars plana vitrectomy (PPV), a surgical procedure used to treat different ophthalmic pathologies, could be associated with moderate to severe eye pain. The aim of the present study was to evaluate the incidence of postoperative eye pain and its risk factors following PPV in a selected population of patients with non-painful eye disease, receiving regional anesthesia and moderate sedation with benzodiazepines, without use of narcotics. METHODS: Single-center, prospective observational cohort study. We recorded the presence of pain at operating room discharge, at 6 and 24 hours, using the numeric rating scale (NRS). We recorded also age, sex, ethnic origin, American Society of Anaesthesia physical status (ASA PS) classification, Charlson Comorbidity Index, the etiology of the vitreoretinal pathology, length of surgery, and type of surgical procedure performed. RESULTS: Eye pain (NRS>3) was present in three patients (0.7%) at operating room discharge, 59 (13.2%) at six and 65 (14.6%) at 24 hours after surgery. LASSO logistic regression analysis identified age, ASA PS, race, along with tamponade as independent risk factors for eye pain at six hours. Scleral buckling was selected for eye pain at 24 hrs. CONCLUSIONS: A protocol for pain control after PPV should be considered, especially in younger, non-Caucasian people, and patients with high ASA PS grade. Moreover, attention must be paid when additional surgical procedures are requested, restricting them to selected patients, and using the appropriate agent for intraocular tamponade.

Design and comparison of the Cs ovens for the test facilities ELISE and SPIDER.

Negative ion sources for fusion rely on the formation of negative hydrogen (or deuterium) ions by conversion of atomic hydrogen and positive hydrogen ions at a low work function caesiated surface. Cs is thus evaporated into the source to decrease the surface work function, which may change due to the removal and redistribution of Cs during plasma phases. To maintain a temporarily stable low work function during 1 h plasma, continuous evaporation of caesium is required, and this is performed by temperature controlled Cs ovens. The Cs ovens for ELISE (IPP Garching) and SPIDER (Consorzio RFX) are based on the evaporation of liquid Cs from a reservoir located at one end of the oven, which is controlled by the reservoir temperature. The ampoule Cs oven of ELISE is in operation since 2015, allowing for controllable and stable evaporation. The SPIDER oven is based on the ELISE oven although it required significant changes due to the vacuum environment and the oven location (at the back-plate instead of the sidewalls), leading to a different design of the oven and the nozzle. First investigations on the SPIDER oven in a dedicated test stand show that Cs evaporation is controllable, stable, and reproducible.

Development and tests of molybdenum armored copper components for MITICA ion source.

In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

MAGnesium-oral supplementation to reduce PAin in patients with severe PERipheral arterial occlusive disease: the MAG-PAPER randomised clinical trial protocol.

INTRODUCTION: Magnesium exerts analgaesic effects in several animal pain models, as well as in patients affected by acute postoperative pain and neuropathic chronic pain. There is no evidence that magnesium can modulate pain in patients with peripheral arterial occlusive disease (PAOD). We describe the protocol of a single-centre randomised double-blind clinical trial aimed at assessing the efficacy of oral magnesium supplementation in controlling severe pain in patients with advanced PAOD. METHODS AND ANALYSIS: Adult patients affected by PAOD at stages III and IV of Lèriche-Fontaine classification, who are opioid-naïve, and who have been admitted to our Acute Pain Service for intractable pain, will be eligible. Patients will be randomised to the control group, treated with standard therapy (oxycodone and pregabalin) plus placebo for 2 weeks, or to the experimental group (standard therapy plus magnesium oxide). Patients will be evaluated on days 0, 2, 4, 6, 8, 12 and 14; the following information will being collected: daily oxycodone dose; average and maximum pain (Numerical Rating Scale); pain relief (Pain Relief Scale); characteristics of the pain (Neuropathic Pain Scale); impact of pain on the patient's daily activities (Brief Pain Inventory). The primary outcome will be oxycodone dosage needed to achieve satisfactory analgaesia on day 14. Secondary outcomes will be pain relief on day 2, time needed to achieve satisfactory analgaesia and time needed to achieve a pain reduction of 50%. A sample size calculation was performed for the primary outcome, which estimated a required sample size of 150 patients (75 per group). ETHICS AND DISSEMINATION: Ethical approval of the study protocol has been obtained from Comitato Etico Provinciale di Brescia, Brescia, Italy. Trial results will be disseminated through scientific journal manuscripts and scientific conference presentations. TRIAL REGISTRATION NUMBER: NCT02455726.