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In this study, we developed a neutron time-of-flight (nTOF) measurement system for a 1.7-MV tandem proton accelerator with a target covered with 300-nm-thick lithium (Li) layer. With implementation of beam chopping module after its ion source, the accelerator is configured to operate in pulsed-beam mode with a pulse width

A Thomson scattering diagnostic system was developed and successfully measured electron temperature and density of core plasma (R = 0.35 m) in Versatile Experiment Spherical Torus (VEST). However, the current system is able to measure only a single time point in a shot. Therefore, upgrade of the Thomson scattering system has been prepared and is in progress to obtain the time evolution. The upgrade is focused on three parts. First, the laser injection system is improved by introducing a burst mode laser with the energy of 2 J and repetition rate of 1 kHz for 10 ms. Furthermore, the laser injection optics is improved to minimize the optical loss. Second, minimum etendue limit of the collection optics is increased by employing a fiber bundle of three single-core fibers. Finally, a data acquisition system is prepared to record the burst laser signals for high sampling rate. Oscilloscope envelope mode is adopted and tested for measuring ten burst laser signal with 1.25 GS/s. Through the upgrade, the time evolution of electron temperature and density is expected to be measured in a single shot with enhanced signal-to-noise ratio.

A Thomson scattering (TS) system has been developed on Versatile Experiment Spherical Torus (VEST) to measure the electron temperature and the density. In VEST, it is quite challenging to measure TS signals because the energy of the utilized pulsed laser and the target electron density are low, 0.85 J and ∼5 × 1018 m−3, respectively. Furthermore, the difficulties caused by filter specifications have to be resolved because of the use of commercial interference filters with broad bandwidth and poor blocking at the laser wavelength. Therefore, we especially optimize the placement order of the filter sets based on the evaluation of the relative errors to overcome the poor spectral resolution. In addition, the amount of the stray light that penetrating filters is reduced by vacuum components such as baffles, louvres, and a viewing dump. With the careful installation and the optimization of the system, we can develop an efficient Thomson scattering system. Recently, TS signals have been successfully measured from the ohmic plasmas, and the electron temperature and the density are determined by analyzing the signals with the Bayesian method.

Some US hemodialysis (HD) facilities switched from oral cinacalcet to intravenous etelcalcetide as the primary calcimimetic therapy to control parathyroid hormone (PTH) levels after the introduction of etelcalcetide in 2017. Although clinical trials have demonstrated the superior efficacy of etelcalcetide versus cinacalcet, evidence comparing real-world effectiveness is lacking.Prospective cohort.Patients receiving HD enrolled in US Dialysis Outcomes and Practice Patterns Study facilities.We classified HD facilities on the basis of whether75% of calcimimetic users were prescribed etelcalcetide ("etelcalcetide-first") or cinacalcet ("cinacalcet-first") from March-August 2019.PTH, calcium, and phosphorus levels among calcimimetic users, all averaged in the 6 months after the exposure assessment period.We used adjusted linear regression to compare outcomes using 2 approaches: (1) cross-sectional comparison of etelcalcetide-first and cinacalcet-first HD facilities; (2) pre-post comparison of HD facilities that switched from cinacalcet-first to etelcalcetide-first using facilities that remained cinacalcet-first as a comparison group.We identified 45 etelcalcetide-first and 67 cinacalcet-first HD facilities; etelcalcetide-first (vs cinacalcet-first) facilities were more likely to be from small or independent dialysis organizations (86% vs 22%) and had higher total calcimimetic use (43% vs 29%) and lower active vitamin D use (66% vs 82%). In the cross-sectional analysis comparing etelcalcetide-first and cinacalcet-first HD facilities, the adjusted mean difference in PTH levels was -115 pg/mL (95% CI, -196 to -34) and the prevalence of a PTH level of600 pg/mL was lower (prevalence difference, -11.4%; 95% CI, -19.3% to -3.5%). Among facilities that switched to etelcalcetide-first, the mean PTH level decreased from 671 to 484 pg/mL and the prevalence of a PTH level of600 pg/mL decreased from 39% to 21%. Among facilities that remained cinacalcet-first, the mean PTH level increased from 632 to 698 pg/mL and the prevalence of a PTH level of600 pg/mL increased from 37% to 43%. The adjusted difference-in-difference between the switch to etelcalcetide-first and the continuation of cinacalcet-first was -169 pg/mL (-249 to -90 pg/mL) for the mean PTH and -14.4% (-22.0% to -6.8%) for a PTH level of600 pg/mL. We also observed slightly lower serum calcium levels and minimal differences in serum phosphorus levels between the etelcalcetide-first and the cinacalcet-first facilities.Residual confounding.We observed better PTH control in HD facilities that switched from using cinacalcet to etelcalcetide as the primary calcimimetic therapy. Further research is needed to investigate how the greater real-world effectiveness of intravenous etelcalcetide (vs oral cinacalcet) may affect clinical outcomes.

This study examines how terrorist attacks and CEO confidence levels impact CEO compensation structures. Terrorist attacks in the United States from 1999 to 2018 are examined as negative exogenous shocks affecting CEO compensation. The findings indicate that overconfident CEOs of affected firms are likely to receive higher equity compensation than overconfident CEOs of firms located far from attacks, while non-overconfident CEOs of affected firms receive higher cash compensation than CEOs located far from attacks. This study contributes to the literature by examining how CEO compensation levels and structures vary according to nonfinancial shocks and CEO confidence levels.

A new method of calculating the beam energy fraction using multiple linear regression (MLR) to ion dump calorimetric data is proposed in Korea Superconducting Tokamak Advanced Research (KSTAR). MLR was applied by collecting the cooling water temperature data from an ion dump calorimeter, where the beam energy fraction directly affects. Through the MLR method, the power delivered to the ion dump can be separated by the beam energy and the beamline A, B, and C, respectively. This power can be converted to the ratio of full, half, and one-third energy particles. By considering the neutralization efficiency, the energy fraction of the source ions and the neutrals can be finally calculated. The beam energy fraction results of the 2019 and 2020 campaign were obtained through this method. For the 2019 campaign, the results were compared with the beam energy fraction obtained using the Doppler shift spectroscopy (DSS) measurement. A notable difference in the first beam energy fraction exists between 2019 and 2020, where A decreases and C increases. This difference in the neutral particle fraction has been understood by the exchange between A and C’s ion buckets.

During the early campaigns of the KSTAR project, feedback control of plasma density has been successfully commissioned at the very first attempt by using a transfer function analysis. In order to minimize a chance of any risk happening, a stable and robust Ohmic discharge was chosen as a test-bed of 300 kA ( I p ) circular limited plasma in 2.0 T ( B t ). Pre-programmed fueling modulation was carried out first by puffing the deuterium gas via a piezoelectric valve. Line-averaged plasma density was measured in real-time by a 280 GHz interferometer system. From those modulations, both the density decay time ( τ i * ) and the external fueling efficiency ( f ex ) were approximated in windows: 3.0–5.0 s and 10–20% respectively. By using the results, a simple plant model has been established based on a global particle balance equation. Then several transient responses such as rising time, settling time and overshoot ratio were estimated in a certain range depending on the windows of τ i * and f ex . It is found that τ i * has little effect on those response characteristics while f ex plays primary role together with magnitude of the proportional gain G P . This is due to predominance of valve response whose characteristic time τ v was approximately 60 ms, which is much shorter than τ i * . Considering the responses, G P for closed-loop control were set initially very low i.e. 2.5 being concerned on excessive fueling. It was followed by several stepwise increments to reduce steady-state error instead of using any integral gain G I to avoid any chance of instability and uncertainty. Similarly, the target density was also initially low and gradually growing. In this way the very first density feedback control was successfully completed although some of the transient responses were different from the anticipated results while the predicted steady-state error was in good agreement with the experimental undershoot. By investigating an arbitrary time delay τ a , it is found that the digital-low-pass filter embedded in the plasma control system (PCS) of 50 ms also plays crucial role together with the τ v . In such way, settling time τ s and low overshoot case were well agreed but rising time t r and strong overshoot were not able to be found with those time delays. Considering well predicted steady-state error, with settling time t s , the transfer function analysis with the simple particle balance model is appropriate for relatively slow responses but not applicable for the faster responses and strong overshoot, which may not be linear-time-invariant (LTI) system anymore. More comprehensive physics-basis modeling will be necessary for more accurate prediction including fast responses and strong overshoot of feedback control of the density.

A D–D neutron generator was developed with an intensity of 108 n/s. A helicon plasma ion source was used to produce a large current deuteron beam, and neutrons were generated by irradiating the deuteron beam on a titanium drive-in target made of commercial pure titanium. The neutron generator was test-run for several hundred hours, and the performances were investigated. The available range of the deuteron beam current was 0.8–8 mA and the beam could be accelerated up to 97.5 keV. The maximum neutron generation rate in the test-runs was 1.9 × 108 n/s, which was achieved by irradiating a 7.6 mA deuteron beam at 94.0 keV on a 0.5 mm-thick target. The operation of the neutron generator was fairly stable, such that the neutron generation rate was not altered by high voltage breakdowns during the test-runs. Neutron generation efficiency was rated as low as 10% when compared to an ideal case of irradiating a 100% monatomic deuteron beam on a perfect TiD2 target. Factors causing the low efficiency were suggested and discussed.