Transmission crystal spectrometers have been fielded at NIF, JLF, LLE, and other major international laser facilities for the purpose of recording survey spectra in the > 6 keV energy range. Spectrometer sensitivities have been measured at the NIST national standard x-ray calibration facility using the absolute NIST exposures (air kerma) to establish an energy-dependent response function. This...
The Laser-driven Ion-beam Trace Probe (LITP) is a new method to diagnose the Bp and Er in tokamaks [1, 2]. It takes full use of four characters of the Laser-driven Ion beam: large energy spread, large pitch angle distribution, short pulse and multiple charge states. Here preliminary experimental results of LITP will be reported. In 2017, lots of LITP experiments were done on the PKU Plasma...
On the quest for an improved understanding of the physics of runaway electrons, there is need to develop diagnostic methods that can provide access to their distribution function. Spectral measurements of the bremsstrahlung spectrum in the gamma-ray energy band are a means to gain insight on confined and escaped runaways as they lose energy in the event of a sudden termination of the plasma...
A large-aperture high-sensitive image intensifier panel consists of an avalanche photodiode array and a LED array was developed. The device has 60% quantum efficiency, 105 photon-to-photon gain, 70-ns time resolution. A gate mode is also available. A panel size is typically 20 cm large but it can be increased with no limitation. An image resolution is limited by the size of a pixel of current...
Based on the charge exchange recombination between fast ions and a neutral beam, fast ion features can be inferred from the Doppler shifted spectrum of Balmer-alpha light from energetic hydrogenic atoms[1]. With the available probe beam, the fast ion D-alpha (FIDA) diagnostic with a spectrometer system (s-FIDA) has been installed and validated on EAST [2,3,4]. In order to study the interaction...
Microwave imaging reflectometry(MIR) system is an advanced imaging system measuring plasma density fluctuations which has already been built and tested. And it will be installed on EAST tokamak. Also the electron cyclotron radiation imaging(ECEI) system has been installed on EAST providing temperature fluctuation information. By combining MIR and ECEI together, temperature and density...
A capability for applying thin film coatings as electrodes in x-ray microchannel plates (MCPs) has been developed at the Nevada National Security Site for the National Nuclear Security Administration community. An electron beam physical vapor deposition system was adapted and modified to implement a well-researched coating process for producing uniform conductive films. Given the exponential...
UCLA is continuing to develop a new generation diagnostic that utilizes cross-polarization scattering [1] (CPS) to measure the fluctuating internal magnetic fields in tokamaks. The CPS technique relies on magnetic turbulence to scatter EM radiation into the perpendicular polarization, enabling a local measurement of the magnetic fluctuations. This is a challenging measurement that addresses...
Recently, a neural network paradigm in our fusion community is regarded as one of the prominent technical breakthroughs by disconnecting the usual anticorrelation between the computational speed and the accuracy of numerical simulation results. If a neural network successfully replicates a computationally intensive simulation code, then the network is likely to reproduce the outputs of the...
A multi-energy soft x-ray (SXR) pinhole camera has been designed and built for the Madison Symmetric Torus (MST) Reversed Field Pinch (RFP) to aid the study of particle and thermal-transport, as well as MHD stability physics. This novel imaging diagnostic technique combines the best features from both pulse-height-analysis and multi-foil methods employing a pixelated x-ray detector in which...
Experiments using the Advanced Radiographic Capability (ARC) laser at the National Ignition Facility (NIF) with recently commissioned capabilities aim to characterize proton beams accelerated via the TNSA mechanism2 for use as both probes and drivers for High-Energy Density Physics experiments. The first measurements of ARC-driven TNSA proton beam characteristics, such as energy spectrum and...
In magnetically confined fusion reactors, heavy impurity ions released by plasma wall interaction and entering the plasma may lead to fuel dilution and degradation of plasma performance by enhanced radiation losses. Therefore, plasma regimes avoiding large impurity influx and impurity accumulation, have to be explored in order to ensure stationary plasma operation. Impurity confinement is...
The Ion Cyclotron Emission (ICE) diagnostic on the DIII-D tokamak advances our understanding of high-frequency energetic particles modes in the 5-200 MHz frequency range and motivates a possible similar ITER diagnostic. This diagnostic consists of ICRF antenna straps configured as receiving antennas and recently restored tile magnetic loop antennas, which have been used to collect a large set...
The next-generation Magnetic Recoil Spectrometer, called MRSt, will provide time-resolved measurements of the DT-neutron spectrum from Inertial Confinement Fusion (ICF) implosions at the National Ignition Facility (NIF). These measurements will provide critical information about the time evolution of the fuel assembly, hot-spot formation, and nuclear burn. The absolute neutron spectrum in the...
Neutral velocity distribution function (NVDF) measurements of Ar-I metastables are demonstrated using single-photon laser induced fluorescence (LIF). These distributions are recorded by actively pumping the 1s5-2p2 (in Paschen’s notation) transition at 696.7352 nm, and observing the 727.494 nm fluorescence to 1s4. We compare 1s5 resonance schemes (at excitation of 706.9167 nm and 714.9012 nm)...
Bent crystals are central to 1-D resolved x-ray spectroscopy and two-dimensional x-ray imaging of plasmas. Nominally identical crystals may differ in their performance with x-rays even though their visible-light images are close to identical. The detailed information needed to understand those differences, viz., the crystal's local diffraction properties over the area that contributes to the...
An 8-channel High-k Scattering system is under development for NSTX- U. The 693 GHz poloidal scattering system replaces a 5-channel 280 GHz toroidal scattering system to study high-k density fluctuations on NSTX-U. The far-infrared (FIR) probe beam launched from Bay G is aimed towards Bay L, where large aperture optics collect radiation at 8 simultaneous scattering angles ranging from 2 to...
An in-situ wavelength calibration system for the X-ray Imaging Crystal Spectrometer (XICS) on W7-X has been developed to provide routine calibration between plasma shots. XICS is able to determine plasma flow profiles by measuring the Doppler shift of x-ray line emission from high charged impurity species. A novel design is described that uses an x-ray tube with a cadmium anode placed in front...
RMP (Resonant Magnetic Perturbation) coils are equipped to study the plasma response to the external magnetic perturbation in tokamaks. In J-TEXT, the static RMP coils have significant impacts on the probes which measure the low frequency signal, such as the locked mode sensor and displacement probes. The contribution on the probes of the RMP coils has been investigated so as to get the error...
Studies of transient plasma events may reveal fast relaxation mechanisms of the plasma pressure or MHD events. A particular application specifying measurement requirements is the fuelling of fusion plasmas with cryogenic pellets. The paper describes a Thomson Scattering System, simultaneously providing electron temperature and density profiles, combining high temporal resolution and adjustable...
Multi-channel absolute extreme ultraviolet (AXUV) photodiodes array diagnostic system has been installed to measure the radiations in a wide spectral range on J-TEXT tokamak. It is dedicated for the studying of the radiation during the thermal quench phase in the disruptions caused by Massive Gas Injection (MGI). A standard method for deriving the local emissivity profiles of the plasma from...
A design is presented of a multichannel x-ray imager spanning energies from 5 to 30 keV for use as a fixed-port diagnostic for OMEGA experiments. The purpose of the absolute, multichannel imaging radiation diagnostic is to infer electron temperature Te and thereby provide a new approach to existing hot-spot temperature and pressure measurements. In contrast to the standard approach of...
A support vector regression (SVR) method is integrated with a collisional radiative (CR) model of the dual-source Helicon-Cathode (HelCat) linear plasma device to determine ArI profiles based on metastable-pumped LIF measurements. A machine learning approach to the CR model allows for an efficient exploration of the input parameter space and can incorporate probe measurement errors for inputs...
We recently developed a one-dimensional imager of neutrons (ODIN) on the Z facility. The instrument is designed for MagLIF experiments, which produce DD neutron yields ~3e12 and, from x-ray imaging, produce a 1-cm long, ~100-µm diameter stagnation column. The small radial extents and present yields precluded useful radial resolution so a one-dimensional imager was developed. The imaging...
ECE radiometers which use variable location channels based on YIG filters improve the precision and the efficiency of measurements of Te profiles and magnetic islands. These variable frequency filters were substituted for fixed filters in the IF section of a radiometer to achieve required higher resolution over a target radial range specified just before the experiment [Truong et al. Sci....
The Orion high-resolution x-ray (OHREX) spectrometer has been a successful tool for measuring the shapes of density-broadened spectral lines produced in short-pulse heated plasmas on the Orion laser facility. We have recently outfitted the instrument with a charge-couple device (CCD) camera, which greatly increased the accuracy with which we can perform line-shift measurements. Because OHREX...
Electron cyclotron heating (ECH) power modulation experiments in GAMMA 10 tandem mirror have been started in order to generate and control the high heat flux and to make the ELM (edge localized mode) like intermittent heat load pattern for divertor simulation studies. Temporally and spatially resolved soft X-ray and end-loss-electron analyses of electron cyclotron heated plasmas are carried...
The single-line-of-sight, time-resolved x-ray imager (SLOS-TRXI) on OMEGA is a new generation of fast-gated x-ray cameras comprising an electron pulse-dilation imager [1] and a nanosecond-gated, burst-mode hybrid complementary metal-oxide semiconductor sensor.[2] SLOS-TRXI images the core of imploded cryogenic deuterium–tritium shells in inertial confinement fusion experiments in the ~4- to...
A system for neutron detection with an ultra-fast digitizer and on-board Field Programmable Gate Array (FPGA) based pulse identification techniques has been implemented on the DIII-D tokamak. The neutron rate measurement is a critical tool for determining the global fast-ion transport, among other uses. Compared to the conventional analog approach with complex Nuclear Instrumentation Module...
The new electron cyclotron emission imaging (ECEI) system is being developed and set up on J-TEXT tokamak. The system includes two separate dual dipole antenna arrays. Each array contains 16(vertical direction) x 8(radial direction) = 128 channels. The quasi-optical system consists of two parts: the imaging optics for plasma imaging and the local oscillator optics for mixers driving. For the...
The present work concerns the first measurements obtained with the visible spectroscopy diagnostic during the WEST start up. The goal of this diagnostic is to measure the PFC sources and the deuterium recycling with spectral, spatial and temporal resolution adapted to the predicted power deposition profiles on the objects observed. Three kinds of PFC are monitored: the ICRH antenna and LHCD...
X-ray imaging optics are finding increased used in high energy density (HED) and inertial confinement fusion (ICF) experiments. Kirkpatrick-Baez microscopes and Wolter optics, for example, have complex point spread functions. Multilayer coated optics will have energy response functions that can vary with off-axis position. It is necessary to calibrate the optical systems in order to take...
Charge Exchange Recombination Spectroscopy (ChERS) diagnostics will provide measurements of ion temperature, velocity and density profiles in C-2W field-reversed configuration (FRC) plasmas. Currently, two diagnostic systems are planned, one for impurity ions and the other dedicated to main ion measurements. Both diagnostic systems will use a common diagnostic neutral beam, currently under...
Magnetic perturbation measurements will be invaluable for characterizing Lithium Tokamak Experiment Beta (LTX-β) plasmas due to the time-evolving, 3D nature of the magnetic fields generated by eddy currents in the vessel and copper shell segments, as well as enhanced MHD instability drive due to newly introduced neutral beam heating. The LTX-β upgrade includes two new arrays of Mirnov coils:...
We have begun using a new generation of high-speed hybrid-CMOS solid-state X-ray framing camera in diagnostics on the Z Facility. Initial applications are in x-ray imaging, spectroscopy, and backlighting. This new camera technology is compact and potentially much simpler to field and operate than traditional microchannel-plate or streak-camera based x-ray imagers. These advantages should...
A cryogenic microjet system has been used for delivering microns-scale continuous liquid hydrogen targets for laser-plasma experiments. This technique has been extended to higher-Z, higher boiling-point gases, including argon and methane. High-resolution shadowgraphy has been used to characterize the jets morphology and pointing stability. A split and delay illumination source has also been...
The temporal response of photodetectors used in nToF diagnostics at the NIF have been characterized to improve uncertainty in, and understanding of, shot parameters obtained from nTOF data. A 1 Hz laser, neutral density glass filters, and electrical attenuators were used to gather statistically-significant samples of photodetector impulse response functions (IRF) in rapid succession....
In C-2W, an elevated impurity concentration, or the presence of high-Z impurities, can account for significant energy losses through radiation. To gauge plasma contamination from impurities, the effective ionic charge (Zeff) can be determined from measurements of Bremsstrahlung continuum radiation over a small spectral range free from line radiation. To this end, an integrated diagnostic...
The spectrometer, described in this paper, employs as the Bragg diffracting element a new type of focusing crystal, which is bent in the shape of a torus with a very large major radius, R, and much smaller, minor radii, ρ, which vary in magnitude and their angle of inclination with respect to the major radius, R, along the crystal surface. The source is placed close to the crystal surface to...
The Experimental Advanced Superconducting Tokamak (EAST) device aims to achieve steady-state operation and long pulse discharge over 1000 seconds. The sampling rate of diagnosis systems usually ranges from 10 KSps to 10 MSps. With the requirement of some particular diagnosis, high-speed acquisition is needed. An embedded system based on FPGA with high-speed, long-time data acquisition is...
Motion Stark Effect (MSE) diagnostic measured the polarization direction of the Stark splitting spectrum of neutral beam to get the internal magnetic field information of Tokamak devices. According to a series of modulation technologies, the tangent value of polarization angle which MSE measured is proportional to the ratio of the second harmonic frequency modulation amplitude of photoelastic...
In the ASDEX Upgrade tokamak, a spatial array of reciprocating fast-ion loss detectors (FILD[1]) is being completed with the imminent installation of a new system[2]. This array of five scintillator-based FILD systems provides time-resolved velocity-space measurements of escaping ions at five different positions in the tokamak probing a large phase-space volume. A new code, FILDSIM[3], has...
In J-TEXT plasma, multiple modes often occur simultaneously, such tearing m/n=2/1 (or 3/1, 5/2) mode, BAE, and even response to Resonant Magnetic Perturbatoins (RMPs), producing complex mixed signal data of magnetic probe array and leading to problems during analysis of modal evolution. Stochastic Subspace Identification (SSI), as method of decomposing multi-mode signals, is applied on J-TEXT...
The soft X-ray pulse height analyzer (PHA) installed at Wendelstein 7-X stellarator is a 3-channel system that collects spectra from 0.25 to 20 keV. X-ray fluxes are line integrated for a line-of-sight that crosses near to the plasma center with temporal and spatial resolution of 100 ms and 2.5 cm (depending on slit sizes). During the 1st W7-X experimental campaign, OP1.1, the PHA was...
A tomographic diagnostic based on measurements of the Hα line emitted after interaction of an H beam with the background gas is under development on the NIO1 test facility. NIO1 is a flexible small ion source producing 9 beamlets at up to 130 mA of H- ions accelerated at 60 KeV. Aim of this device is to investigate the physics of negative ion production, extraction and acceleration as well as...
The ion temperature in VEST (Versatile Experiment Spherical Torus) is expected to increase with the neutral beam injection (NBI) heating and will be measured with emission spectroscopy. However, the temperature at the plasma edge still remains rather low, thus requiring a reliable spectroscopy technique with sufficient spectral resolution. Since the VEST system operates in a single pulse...
Neutron emission profile has been measured in NB-heated deuterium plasmas of LHD by using the vertical neutron camera (VNC) to obtain radial profile of beam ions. The fundamental performance test of the stilbene detector (SD) used for the VNC is performed as part of commissioning for the system. The detector responses to various energies of fast neutron were examined in accelerator-type...
Understanding runaway electrons is a crucial topic for today’s tokamaks and for ITER. A new compact gamma-ray spectrometer was developed in order to optimise the measurement of Bremsstrahlung radiation emitted from these highly energetic particles. A LYSO:Ce scintillator crystal was chosen for its good light yield, high efficiency and fast decay time. The crystal was coupled to silicon...
Stable confinement of high-beta (local electron beta ~ 1) is demonstrated with high-energy electrons (T_e > 10 keV) by an X-ray measurement in the RT-1 magnetospheric plasmas. A new Nd:YAG laser Thomson scattering (TS) system has been developed to investigate the mechanism of the high-beta plasma formation in the RT-1. The designed parameters for the TS system is 10 eV < T_e < 50 keV and n_e >...
For the edge CXRS on EAST, the ACX signal is strongly overlapped with passive signals, and the CXRS measurements are compounded spectra consisting of ACX signal and line-integrated background passive signal. Therefore, the analysis and understanding of passive emission is crucial to exclude its influence on the measurement of the ACX. The 1-D impurity transport code STRAHL is used to study the...
To understand the erosion effect of neutral particles on the first wall, a time-of-flight low energy neutral particle analyzer (LENPA) has been developed on EAST tokamak. The LENPA mounted on the EAST mid-plane consists of a chopper system, a 3 m long flight tube, two sets of detector assemblies and data acquisition, vacuum, power supply and control systems. The neutral outflux is gated in...
Measurement and control of plasma current density profile is crucial for high performance scenario development on EAST [1]. As a local magnetic measurement technique, the Motional Stark Effect (MSE) diagnostic, which employs the spectrum of injected neutral beams, is widely adopted. Recently, a multi-channel MSE diagnostic was designed and deployed on EAST. An integrated periscope, which is...
This paper presents a methods for the intrinsic impurity concentration measurements by means of VUV and SXR diagnostics on the JET-ILW tokamak. Measurements of mid-Z impurities content were obtained by means of VUV spectra. To provide absolute concentrations a new relative calibration technique has been proposed. It’s based on cross-calibration with calibrated spectrometer by using unresolved...
A diagnostic neutral beam or heating neutral beam provides a population of high energy neutrals for active beam plasma diagnostics in fusion plasmas such as charge exchange recombination spectroscopy. Accurate modeling of the local density of beam neutrals is needed for interpretation of diagnostic data. A simple and fast model has been developed to calculate 3D density distribution of beam...
Velocity-space tomography provides a way of diagnosing fast ions in a fusion plasma by combining measurement from multiple instruments. We use a tangentially viewing and a perpendicularly viewing fast-ion D-alpha (FIDA) diagnostic installed on the spherical tokamak MAST (before the upgrade) to do velocity space tomography of the fast-ion distribution function. To make up for the scarce amount...
