Development of the 174 GHz collective Thomson scattering diagnostics at Wendelstein 7-X

In this paper, we present the design and commissioning results of the upgraded collective Thomson scattering diagnostic at the Wendelstein 7-X stellarator. The diagnostic has a new radiometer designed to operate between the second and third harmonics of the electron cyclotron emission from the plasma at 171-177 GHz, where the emission background has a minimum and is of order 10-100 eV. It allows us to receive the scattered electromagnetic field with a significantly improved signal-to-noise ratio and extends the set of possible scattering geometries compared to the case of the original instrument operated at 140 GHz. The elements of the diagnostic are a narrowband notch filter and a frequency stabilized probing gyrotron that will allow measuring scattered radiation spectra very close to the probing frequency. Here, we characterize the microwave components applied to the radiometer and demonstrate the performance of the complete system that was achieved during the latest experimental campaign, OP2.1.

Co-Occurrence of Sarcopenia and Frailty in Acutely Admitted Older Medical Patients: Results from the Copenhagen PROTECT Study

BACKGROUND

Sarcopenia and frailty are often used interchangeably in clinical practice yet represent two distinct conditions and require different therapeutic approaches. The literature regarding the co-occurrence of both conditions in older patients is scarce as most studies have investigated the prevalence of sarcopenia and frailty separately.

OBJECTIVES

We aim to evaluate the prevalence and co-occurrence of sarcopenia and frailty in a large sample of acutely admitted older medical patients.

DESIGN

Secondary analyses using cross-sectional data from the Copenhagen PROTECT study.

SETTING

Patients were included from the acute medical ward at Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark, between November 2019 and November 2021.

PARTICIPANTS

Acutely admitted older medical patients (≥65 years).

MEASUREMENTS

Handgrip strength (HGS) was investigated using a handheld dynamometer. Lean mass (SMI) was investigated using direct-segmental multifrequency bioelectrical impedance analyses (DSM-BIA). Low HGS, low SMI, and sarcopenia were defined according to the recent definitions from the European Working Group on Sarcopenia in Older People (EWGSOP2). The Clinical Frailty Scale (CFS) was used to evaluate frailty, with a value > 5 indicating the presence of frailty. Patients were enrolled and tested within 24 hours of admission.

RESULTS

This study included 638 patients (mean age: 78.2±7.6, 55% female) with complete records of SMI, HGS, and the CFS. The prevalence of low HGS, low SMI, sarcopenia, and frailty were 39.0%, 33.1%, 19.7%, and 39.0%, respectively. Sarcopenia and frailty co-occurred in 12.1% of the patients.

CONCLUSIONS

It is well-known that sarcopenia and frailty represent clinical manifestations of ageing and overlap in terms of the impairment in physical function observed in both conditions. Our results demonstrate that sarcopenia and frailty do not necessarily co-occur within the older acutely admitted patient, highlighting the need for separate assessments of frailty and sarcopenia to ensure the accurate characterization of the health status of older patients.

Parametric Decay Instabilities during Electron Cyclotron Resonance Heating of Fusion Plasmas, Problems and Possibilities

We review parametric decay instabilities (PDIs) expected in connection with electron cyclotron resonance heating (ECRH) of magnetically confined fusion plasmas, with a specific focus on conditions relevant for the ITER tokamak. PDIs involving upper hybrid (UH) waves are likely to occur in O-mode ECRH scenarios at ITER if electron density profiles allowing trapping of UH waves near the ECRH frequency are present. Such PDIs may occur near the plasma center in ITER full-field scenarios heated by 170 GHz O-mode ECRH and on the high-field side of half-field ITER plasmas heated by 110 GHz or 104 GHz O-mode ECRH. Additionally, 110 GHz O-mode ECRH of half-field ITER scenarios may have low ECRH absorption, due to the electron cyclotron resonance being located on the high-field side of the main plasma. This potentially allows PDIs driven by a significant amount of ECRH radiation reaching the UH resonance in X-mode to occur, as X-mode radiation can be generated by reflection of unabsorbed O-mode radiation from the high-field side wall. The occurrence of PDIs during ECRH may damage microwave diagnostics, such as the electron cyclotron emission and low-field side reflectometer systems at ITER, as well as complicate the calculation of heating and current drive characteristics. However, if PDIs are induced in a controlled manner, they may provide novel diagnostic tools and allow the generation of a moderate fast ion population in plasmas heated only by ECRH.

Inflammatory bowel disease at a young age – implications for achieving upper secondary education

Background

The incidence of inflammatory bowel disease (IBD) among children and adolescence is increasing worldwide. Having a chronic condition at a young age may affect educational achievement and later employment and self-support. The study aims to examine the impact of being diagnosed with IBD before 18 years of age on achieving an upper secondary education before 25 years of age.

Methods

Using the Danish National Patient Register (1980-2018) all patients (born 1970-1994) diagnosed with IBD at a young age (<18 years) were identified. The IBD-patients were matched on age and sex with 10 references without IBD at the index date (date of diagnosis of IBD). The outcome was achieving an upper secondary education using data from Danish Education Registers. The association between IBD diagnosis and achieving an upper secondary education was analyzed using Cox regression with robust variance estimation adjusting for parents’ highest educational level. Furthermore, stratified analyses were performed on parental socioeconomic status (education and income).

Results

We identified 3,178 patients with IBD: Crohn’s disease (CD) n = 1,344, Ulcerative colitis (UC) n = 1,834. Reference n = 28,220. The median age at diagnosis was 15.3 years (IQR: [13.0;16.9]). At the age of 25 74.0% (CI: 71.6-76.4) for CD, 75.8% (CI: 73.8-77.8) for UC, and 69.7% (CI: 69.2-70.3) for references had achieved an upper secondary education. The adjusted Hazard ratio (HR) of achieving an upper secondary education was 1.05 (CI: 1.00 -1.11) for CD and 1.09 (CI: 1.04 -1.15) for UC. When stratifying the IBD-patient with the lowest socioeconomic status performed better than their peers.

Conclusions

Being diagnosed with IBD before 18 years of age did not reduce the chance of achieving an upper secondary education. Patients with low socioeconomic status performed better than their peers, however the study gives no explanation of this.

Key messages

• Children diagnosed with IBD before 18 years of age had at least the same chance of achieving an upper secondary education compared to references.

• IBD patients with low social economic status performed better than their peers.

Effect of supervised high-intensity interval training on haemostasis in patients with coronary artery disease: a randomised controlled trial

Background

Regular exercise training is recommended for patients with stable coronary artery disease (CAD), because it improves quality of life and reduces cardiovascular mortality and hospital admissions. CAD patients benefit from anti-thrombotic therapy and may have a pro-coagulant condition compared to healthy individuals. Long-term exercise training may reduce platelet aggregation and coagulation and increase fibrinolysis.

Purpose

We aimed to investigate if supervised high-intensity interval training affects haemostasis in patients with stable CAD.

Methods

We randomised stable CAD patients to supervised high-intensity interval training or standard care. High-intensity exercise training was performed on rowing ergometers three times weekly for 12 weeks. Blood samples were obtained in all patients prior to randomisation (baseline) and after 6 and 12 weeks. We evaluated platelet aggregation with the Multiplate® Analyzer, thrombin generation using the Calibrated Automated Thrombogram and fibrinolysis employing an in-house clot lysis assay. Between group differences were evaluated with mixed model analysis using SPSS. According to our sample size calculation, we have a statistical power of 88% to detect a difference of 25% in clot lysis time.

Results

A total of 142 patients with stable CAD (mean age 67±9 years, 83% males) completed the study; 64 in the exercise group and 78 in the control group. The weekly average active training duration was 54 min, and adherence to training was 97%. When comparing the two groups (exercise vs. standard care) from baseline to post intervention, we found no significant changes in ADP-induced platelet aggregation (difference between baseline and 12 weeks (Δ) 11 AU·min, 95% confidence interval (CI): −46–68 in the exercise group and Δ24 AU·min, 95% CI: −28–77 in the standard care group, p=0.52), thrombin generation (endogenous thrombin potential Δ45 nM·min, 95% CI: −77–166 in the exercise group and Δ103 nM·min, 95% CI: −7–212 in the standard care group, p=0.18) or fibrinolysis (50% clot lysis time Δ62 sec, 95% CI: −136–261 in the exercise group and Δ215 sec, 95% CI: 38–391 in the standard care group, p=0.39).

Conclusion

High-intensity interval training did not have major effects on platelet aggregation, thrombin generation nor fibrinolysis in patients with stable CAD.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Aarhus UniversityThe Faroese Health Research Foundation (Sjúkrakassagrunnurin)

ITER collective Thomson scattering-Preparing to diagnose fusion-born alpha particles (invited)

The ITER Collective Thomson scattering (CTS) diagnostic will measure the dynamics of fusion-born alpha particles in the burning ITER plasma by scattering a 1 MW 60 GHz gyrotron beam off fast-ion induced fluctuations in the plasma. The diagnostic will have seven measurement volumes across the ITER cross section and will resolve the alpha particle energies in the range from 300 keV to 3.5 MeV; importantly, the CTS diagnostic is the only diagnostic capable of measuring confined alpha particles for energies below ∼1.7 MeV and will also be sensitive to the other fast-ion populations. The temporal resolution is 100 ms, allowing the capture of dynamics on that timescale, and the typical spatial resolution is 10-50 cm. The development and design of the in-vessel and primary parts of the CTS diagnostic has been completed. This marks the beginning of a new phase of preparation to maximize the scientific benefit of the diagnostic, e.g., by investigating the capability to contribute to the determination of the fuel-ion ratio and the bulk ion temperature as well as integrating data analysis with other fast-ion and bulk-ion diagnostics.

Choosing wisely in burn care

BACKGROUND

The Choosing Wisely Campaign was launched in 2012 and has been applied to a broad spectrum of disciplines in almost thirty countries, with the objective of reducing unnecessary or potentially harmful investigations and procedures, thus limiting costs and improving outcomes. In Canada, patients with burn injuries are usually initially assessed by primary care and emergency providers, while plastic or general surgeons provide ongoing management. We sought to develop a series of Choosing Wisely statements for burn care to guide these practitioners and inform suitable, cost-effective investigations and treatment choices.

METHODS

The Choosing Wisely Canada list for Burns was developed by members of the Canadian Special Interest Group of the American Burn Association. Eleven recommendations were generated from an initial list of 29 statements using a modified Delphi process and SurveyMonkey™.

RESULTS

Recommendations included statements on avoidance of prophylactic antibiotics, restriction of blood products, use of adjunctive analgesic medications, monitoring and titration of opioid analgesics, and minimizing 'routine' bloodwork, microbiology or radiological investigations.

CONCLUSIONS

The Choosing Wisely recommendations aim to encourage greater discussion between those involved in burn care, other health care professionals, and their patients, with a view to reduce the cost and adverse effects associated with unnecessary therapeutic and diagnostic procedures, while still maintaining high standards of evidence-based burn care.

Fast-ion orbit sensitivity of neutron emission spectroscopy diagnostics

Fast ions in fusion plasmas often leave characteristic signatures in the plasma neutron emission. Measurements of this emission are subject to the phase-space sensitivity of the diagnostic, which can be mapped using weight functions. In this paper, we present orbit weight functions for the TOFOR and NE213 neutron diagnostics at the Joint European Torus, mapping their phase-space sensitivity in 3D orbit space. Both diagnostics are highly sensitive to fast ions that spend a relatively large fraction of their orbit transit times inside the viewing cone of the diagnostic. For most neutron energies, TOFOR is found to be relatively sensitive to potato orbits and heavily localized counter-passing orbits, as well as trapped orbits whose "banana tips" are inside the viewing cone of TOFOR. For the NE213-scintillator, the sensitivity is found to be relatively high for stagnation orbits.

Fast production of microwave component prototypes by additive manufacturing and copper coating

We present a novel method for efficient production of prototypes of microwave components by fused depositing modeling, also known as 3D plastic printing, and vapor deposition coating of a 1 μm copper layer. We demonstrate that the properties of the components follow the predicted performance for low power microwave propagation. The production method offers new opportunities for cheap and efficient production of mock-ups and prototypes of advanced-geometry components for tests with low-power microwaves.

Craniopharyngiomas: experience and results

INTRODUCTION

Craniopharyngiomas are a big challenge in the neurosurgical field. Because these lesions involve important systems, surgeons must weigh the risks of aggressive resection against the long-term challenges of recurrence. We present the outcomes of our patients based on clinical results, degree of resection, recurrence and disease-free survival.

MATERIALS AND METHODS

We reviewed medical records in all patients who had undergone surgical resection for craniopharyngioma at (Hospital Italiano de Buenos Aires) between 2007 and 2019. We considered ophthalmological examinations, imaging studies, endocrinological studies and surgical complications. Radical resections were planned in all of the patients. To help choose the correct surgical approach, craniopharyngiomas were classified based on tumor location.

RESULTS

Thirty cases of craniopharyngioma were analysed. 12.5% were classified as intrasellar, 12.5% as prechiasmatic, 43.75% as retrochiasmatic, and 31.25% as intraventricular. Overall, 38 cases involved a transcranial surgery (15 orbitozygomatic approach; 19 pterional approach and 4 transcallosal approach), seven involved a transsphenoidal approach, two microscopic transnasal approach and one ventricular endoscopy for emptying the craniopharyngioma cyst. Gross-total resection was achieved in 43.7% and near-total resection (more than 90%) in 25%. The mean follow-up period after resection was 4.7 years. Tumor recurrence occurred in 48%, with an average of 42.7 disease-free months.

CONCLUSION

Total tumor resection is the best treatment for craniopharyngioma. Due to its high morbidity and mortality, a multidisciplinary team is necessary for the management of these tumors.

Understanding the impacts of groundwater abstraction through long-term trends in water quality

It is vital to understand long-term trends in water quality parameters when assessing the sustainability of groundwater abstraction. Withdrawal-to-availability analysis is still used widely in groundwater management considering quantities and utilization rates based on in- and outflows. In this study, we took a step further than the water balance approach and carried out a detailed investigation of trends in long-term time series of groundwater quality, in order to analyze the sustainability of groundwater abstraction. We assessed trends, links, and patterns in abstraction, potentiometric surface, and water quality parameters for 28 well fields around Copenhagen, Denmark. Groundwater monitoring data from 1900 until 2014 were investigated for each well field. During this period, the well fields experienced a 2-14 m decrease in the nearby potentiometric surface compared to the first-or pre-pumping-potentiometric surface recordings. Sulfate concentrations increased in 25 out of 27 well fields after the maximum abstraction period, compared to the earliest water quality measurements. The results indicate that in the 1980s, when water consumption (abstraction) and drawdown were at their highest, water abstraction caused a steady increase in sulfate and calcium, which we consider unsustainable. In contradiction, the abstraction in 24 well fields show almost steady sulfate levels in the aquifer after decreased water consumption since 1995. Only four well fields showed more than a 20 mg/L increase in sulfate concentration, which indicates that the recent abstraction does not interfere with sulfate levels in the aquifer. Our method and results show how long-term water quality trends can support the management of aquifer exploitation and evaluate sustainability on the well field scale.

Observation and Modelling of the Onset of Parametric Decay Instabilities during Gyrotron Operation at ASDEX Upgrade

We investigate parametric decay instabilities (PDIs) occurring for gyrotron radiation near the upper hybrid resonance at the ASDEX Upgrade tokamak. The PDIs are observed through anomalous millimeter-wave scattering which is recorded using the high-resolution, fast acquisition collective Thomson scattering system installed at ASDEX Upgrade, and an experiment in which such observations are made during a scan of the toroidal magnetic field is performed. A previously published theoretical model is used to calculate the gyrotron power necessary to excite PDIs in the experiment; the theoretical model is capable of predicting whether or not PDIs will be observed at a given toroidal magnetic field with a high degree of accuracy.

Collective Thomson scattering diagnostic at Wendelstein 7-X

A Collective Thomson Scattering (CTS) diagnostic is installed at Wendelstein 7-X for ion temperature measurements in the plasma core. The diagnostic utilizes 140 GHz gyrotrons usually used for electron cyclotron resonance heating (ECRH) as a source of probing radiation. The CTS diagnostic uses a quasi-optical transmission line covering a distance of over 40 m. The transmission line is shared between the ECRH system and the CTS diagnostic. Here we elaborate on the design, installation, and alignment of the CTS diagnostic and present the first measurements at Wendelstein 7-X.

Observations of core ion cyclotron emission on ASDEX Upgrade tokamak

The B-dot probe diagnostic suite on the ASDEX Upgrade tokamak has recently been upgraded with a new 125 MHz, 14 bit resolution digitizer to study ion cyclotron emission (ICE). While classic edge emission from the low field side plasma is often observed, we also measure waves originating from the core with fast fusion protons or beam injected deuterons being a possible emission driver. Comparing the measured frequency values with ion cyclotron harmonics present in the plasma places the origin of this emission on the magnetic axis, with the fundamental hydrogen/second deuterium cyclotron harmonic matching the observed values. The actual values range from ∼27 MHz at the on-axis toroidal field B_T = -1.79 T to ∼40 MHz at B_T = -2.62 T. When the magnetic axis position evolves during this emission, the measured frequency values track the changes in the estimated on-axis cyclotron frequency values. Core ICE is usually a transient event lasting ∼100 ms during the neutral beam startup phase. However, in some cases, core emission occurs in steady-state plasmas and lasts for longer than 1 s. These observations suggest an attractive possibility of using a non-perturbing ICE-based diagnostic to passively monitor fusion alpha particles at the location of their birth in the plasma core, in deuterium-tritium burning devices such as ITER and DEMO.

Integrating groundwater stress in life-cycle assessments - An evaluation of water abstraction

Understanding groundwater abstraction effects is vital for holistic impact assessments in areas depending on groundwater resources. The objective of our study was to modify the state-of-the-art AWaRe (available water remaining), freshwater impact assessment specifically for use in LCAs in areas dependent on groundwater resources. The new method, called "AGWaRe" (available groundwater remaining), reflects groundwater availability, based on a fraction of available groundwater remaining locally relative to a reference. Furthermore, our method increases spatial resolution beyond 1770 km² grid cells and adjusts demarcations in order to improve the representation of the heterogeneity of groundwater catchments. The applicability of AGWaRe was demonstrated on three groundwater systems producing 5 million m³ water for the city of Copenhagen, namely Advanced Treatment of Groundwater, Simple Treatment of Groundwater and Infiltration of Reclaimed water. Results were normalised to compare with other effects of supplying water to an average Danish person. The normalised impacts for drinking water for one person ranged between 0.1 and 39 PE (person equivalent) for the three systems, which indicates that effects on groundwater resources differ substantially between systems. A comparative LCA of these groundwater systems shows that other impact categories range between 0 and 1 PE/person. Advanced Treatment of Groundwater generally has the lowest effect, for example <50% of the other groundwater systems in Global Warming Potential. The AGWaRe results indicate that freshwater impacts from Simple Treatment of Groundwater are up to 100 times greater than for Infiltration of Reclaimed water. Furthermore, AGWaRe exposes differences between the groundwater systems that AWaRe cannot evaluate, because one AWaRe cell covers two of the systems in question. These improvements are crucial for groundwater managers looking to include sustainability considerations in their analysis and decision-making.

Is There an Enhancing Effect of Neuroleptic Drugs on Blood Coagulation and Thrombosis

Sordinol (R), (clopenthixol, W.H. 0.), a potent sedative of the thiaxanthene group, in the concentrations used therapeutically, had no direct influence on blood coagulation as investigated by the thrombin generation test and the thromboplastin activation test. No significant direct effect on the fibrinolytic system was observed using urokinase, streptokinase activated human euglobulin, trypsin, porcine plasmin, or human plasmin. There was no effect on the urokinase-inhibiting effect of normal human plasma. The influence of the immobilization produced by heavy sedation on the development of thrombotic states is discussed. When the effects of drugs are evaluated it is necessary to distinguish between the direct effect of the drug and secondary effects caused by the treatment.

Subcortical volumetric abnormalities in bipolar disorder

Considerable uncertainty exists about the defining brain changes associated with bipolar disorder (BD). Understanding and quantifying the sources of uncertainty can help generate novel clinical hypotheses about etiology and assist in the development of biomarkers for indexing disease progression and prognosis. Here we were interested in quantifying case-control differences in intracranial volume (ICV) and each of eight subcortical brain measures: nucleus accumbens, amygdala, caudate, hippocampus, globus pallidus, putamen, thalamus, lateral ventricles. In a large study of 1710 BD patients and 2594 healthy controls, we found consistent volumetric reductions in BD patients for mean hippocampus (Cohen's d=-0.232; P=3.50 × 10-7) and thalamus (d=-0.148; P=4.27 × 10-3) and enlarged lateral ventricles (d=-0.260; P=3.93 × 10-5) in patients. No significant effect of age at illness onset was detected. Stratifying patients based on clinical subtype (BD type I or type II) revealed that BDI patients had significantly larger lateral ventricles and smaller hippocampus and amygdala than controls. However, when comparing BDI and BDII patients directly, we did not detect any significant differences in brain volume. This likely represents similar etiology between BD subtype classifications. Exploratory analyses revealed significantly larger thalamic volumes in patients taking lithium compared with patients not taking lithium. We detected no significant differences between BDII patients and controls in the largest such comparison to date. Findings in this study should be interpreted with caution and with careful consideration of the limitations inherent to meta-analyzed neuroimaging comparisons.

Consensus Statements On Cognitive Dysfunction In Depression In The Uk: Rationale And Process For Gaining Consensus

Introduction

Cognitive dysfunction is an important aspect of depression that includes problems with thinking, concentration and memory. Research suggests that the cognitive aspect of depression is highly prevalent and has a significant impact on patient functioning. Currently, cognitive dysfunction in depression is largely unrecognised, unmonitored and untreated.

Aims

We aim to define cognitive dysfunction in clinical depression (major depressive disorder) and explore its detection and management in the UK, highlighting priority areas to be addressed.

Methods

A modified Delphi method was used as the process to gain consensus. A multi-stakeholder steering committee of depression experts (including psychiatrists, psychologists, primary care physicians, and representatives from occupational therapy and a depression charity) provided the key themes and, through round-table discussion, developed draft statements. The main areas of focus were burden, detection and management of cognitive dysfunction in depression. These statements formed a questionnaire to be reviewed by 150–200 health-care professionals with an involvement in the management of depression, with level of agreement noted as ‘strongly disagree’, ‘disagree’, ‘don’t know/uncertain’, ‘agree’ or ‘strongly agree’. Responses to the questionnaire will be analysed (very high agreement [> 66%] or very low agreement [< 33%]) and the steering committee will revise and finalise the consensus statements, and identify priority areas for future consideration. The steering committee was initiated and supported by the pharmaceutical company Lundbeck Ltd, through an educational grant. Lundbeck Ltd did not influence content.

Results

Results of the questionnaire and the evolution of the final consensus statements will be presented.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Carnitine levels in skeletal muscle, blood, and urine in patients with primary carnitine deficiency during intermission of L-carnitine supplementation

BACKGROUND

Primary carnitine deficiency (PCD) is a disorder of fatty acid oxidation with a high prevalence in the Faroe Islands. Only patients homozygous for the c.95A>G (p.N32S) mutation have displayed severe symptoms in the Faroese patient cohort. In this study, we investigated carnitine levels in skeletal muscle, plasma, and urine as well as renal elimination kinetics before and after intermission with L-carnitine in patients homozygous for c.95A>G.

METHODS

Five male patients homozygous for c.95A>G were included. Regular L-carnitine supplementation was stopped and the patients were observed during five days. Blood and urine were collected throughout the study. Skeletal muscle biopsies were obtained at 0, 48, and 96 h.

RESULTS

Mean skeletal muscle free carnitine before discontinuation of L-carnitine was low, 158 nmol/g (SD 47.4) or 5.4% of normal. Mean free carnitine in plasma (fC0) dropped from 38.7 (SD 20.4) to 6.3 (SD 1.7) μmol/L within 96 h (p < 0.05). Mean T 1/2 following oral supplementation was approximately 9 h. Renal reabsorption of filtered carnitine following oral supplementation was 23%. The level of mean free carnitine excreted in urine correlated (R (2) = 0.78, p < 0.01) with fC0 in plasma.

CONCLUSION

Patients homozygous for the c.95A>G mutation demonstrated limited skeletal muscle carnitine stores despite long-term high-dosage L-carnitine supplementation. Exacerbated renal excretion resulted in a short T 1/2 in plasma carnitine following the last oral dose of L-carnitine. Thus a treatment strategy of minimum three daily separate doses of L-carnitine is recommended, while intermission with L-carnitine treatment might prove detrimental.

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR.

Resolving the bulk ion region of millimeter-wave collective Thomson scattering spectra at ASDEX Upgrade

Collective Thomson scattering (CTS) measurements provide information about the composition and velocity distribution of confined ion populations in fusion plasmas. The bulk ion part of the CTS spectrum is dominated by scattering off fluctuations driven by the motion of thermalized ion populations. It thus contains information about the ion temperature, rotation velocity, and plasma composition. To resolve the bulk ion region and access this information, we installed a fast acquisition system capable of sampling rates up to 12.5 GS/s in the CTS system at ASDEX Upgrade. CTS spectra with frequency resolution in the range of 1 MHz are then obtained through direct digitization and Fourier analysis of the CTS signal. We here describe the design, calibration, and operation of the fast receiver system and give examples of measured bulk ion CTS spectra showing the effects of changing ion temperature, rotation velocity, and plasma composition.