VUV spectroscopy in impurity injection experiments at KSTAR using prototype ITER VUV spectrometer.

The ITER vacuum ultra-violet (VUV) core survey spectrometer has been designed as a 5-channel spectral system so that the high spectral resolving power of 200-500 could be achieved in the wavelength range of 2.4-160 nm. To verify the design of the ITER VUV core survey spectrometer, a two-channel prototype spectrometer was developed. As a subsequent step of the prototype test, the prototype VUV spectrometer has been operated at KSTAR since the 2012 experimental campaign. From impurity injection experiments in the years 2015 and 2016, strong emission lines, such as Kr xxv 15.8 nm, Kr xxvi 17.9 nm, Ne vii 46.5 nm, Ne vi 40.2 nm, and an array of largely unresolved tungsten lines (14-32 nm) could be measured successfully, showing the typical photon number of 1013-1015 photons/cm2 s.

Resultados precoces y tardíos en resecciones ampliadas en cáncer de colon T4b / Early and late results after multivisceral resections for T4b colonic cancer

Objetivos: Describir las tasas de morbilidad y mortalidad postoperatorias de las resecciones ampliadas de colon en pacientes con tumor en estadio T4b. Material y métodos: Serie de casos, que incluye pacientes con adenocarcinoma colónico clínicamente con compromiso de estructuras adyacentes (T4b), intervenidos de resección multivisceral entre los años 2005 y 2014. Fueron excluidos pacientes con metástasis, con bordes macroscópicamente comprometidos y con datos clínicos incompletos. Las variables resultado fueron la morbilidad y mortalidad postoperatorias a los 30 días. Se aplicó estadística descriptiva. Para las variables categóricas se utilizaron porcentajes, y para las variables continuas se utilizaron la media y mediana como medidas de tendencia central y la desviación estándar o rango como medidas de dispersión. Se aplicó el método de Kaplan-Meier para la sobrevida, y pruebas de Chi cuadrado y log-Rank para el análisis de sobrevida por subgrupos. Resultados: De un universo de 483 pacientes intervenidos por adenocarcinoma colónico, 71 fueron T4b. Se aplicaron criterios de exclusión, resultando una muestra de 46 pacientes. Los órganos más frecuentemente comprometidos fueron: intestino delgado, epiplón, pared abdominal y otro segmento colónico. La morbilidad y mortalidad postoperatorias, de un 21,7 y un 6,5%, respectivamente. Influyeron significativamente en la sobrevida la edad, el antecedente de quimioterapia adyuvante, la presencia de inestabilidad microsatelital y la diferenciación del tumor. Conclusiones: El compromiso multivisceral de los tumores colónicos no es infrecuente, con un 9,5% para nuestra serie. La resección R0 es el tratamiento de elección. Influyen en el pronóstico el tipo histológico y el comportamiento biológico del tumor, así como la quimioterapia adyuvante y la edad del paciente.

Aims: To describe postoperative morbidity and mortality rates in multivisceral resections for T4b colon cancer. Material and methods: Case series of patients diagnosed of T4b colonic adenocarcinoma who underwent multivisceral resection between 2005 and 2014. There were excluded those patients who had metastases, R2 resection and incomplete clinical data. Result variables were morbidity and mortality at 30 days. It was performed descriptive statistic using percentage estimation for categories, average and median for continuous variables and standard deviation or rank as measures of statistical dispersion. It was used Kaplan-Meier method for survival and chi-square and log-Rank for subgroups analysis. Results: From a universe of 483 patients who underwent surgery for colonic adenocarcinoma, whom 71 were staged as T4b, after exclusion criteria were applied it resulted a sample of 46 patients. The small bowel, omentum, abdominal wall and other colonic segment were the more often compromised organs. Postoperative morbidity and mortality were 21.7 and 6.5% respectively. The age, history of adjuvant chemotherapy, presence of microsatellite instability and tumor differentiation had a significant impact in survival. Conclusions: Multivisceral affection in colonic cancer is not uncommon, 9.5% in our series. R0 resection is the treatment of choice. Patient outcome depends on his age, histologic and biologic characteristics of the tumor and adjuvant treatment.

Overview of diagnostic performance and results for the first operation phase in Wendelstein 7-X (invited).

Wendelstein 7-X, a superconducting optimized stellarator built in Greifswald/Germany, started its first plasmas with the last closed flux surface (LCFS) defined by 5 uncooled graphite limiters in December 2015. At the end of the 10 weeks long experimental campaign (OP1.1) more than 20 independent diagnostic systems were in operation, allowing detailed studies of many interesting plasma phenomena. For example, fast neutral gas manometers supported by video cameras (including one fast-frame camera with frame rates of tens of kHz) as well as visible cameras with different interference filters, with field of views covering all ten half-modules of the stellarator, discovered a MARFE-like radiation zone on the inboard side of machine module 4. This structure is presumably triggered by an inadvertent plasma-wall interaction in module 4 resulting in a high impurity influx that terminates some discharges by radiation cooling. The main plasma parameters achieved in OP1.1 exceeded predicted values in discharges of a length reaching 6 s. Although OP1.1 is characterized by short pulses, many of the diagnostics are already designed for quasi-steady state operation of 30 min discharges heated at 10 MW of ECRH. An overview of diagnostic performance for OP1.1 is given, including some highlights from the physics campaigns.

Status of the diagnostics development for the first operation phase of the stellarator Wendelstein 7-X.

An overview of the diagnostics which are essential for the first operational phase of Wendelstein 7-X and the set of diagnostics expected to be ready for operation at this time are presented. The ongoing investigations of how to cope with high levels of stray Electron Cyclotron Resonance Heating (ECRH) radiation in the ultraviolet (UV)/visible/infrared (IR) optical diagnostics are described.

Test of prototype ITER vacuum ultraviolet spectrometer and its application to impurity study in KSTAR plasmas.

To optimize the design of ITER vacuum ultraviolet (VUV) spectrometer, a prototype VUV spectrometer was developed. The sensitivity calibration curve of the spectrometer was calculated from the mirror reflectivity, the grating efficiency, and the detector efficiency. The calibration curve was consistent with the calibration points derived in the experiment using the calibrated hollow cathode lamp. For the application of the prototype ITER VUV spectrometer, the prototype spectrometer was installed at KSTAR, and various impurity emission lines could be measured. By analyzing about 100 shots, strong positive correlation between the O VI and the C IV emission intensities could be found.

First fusion proton measurements in TEXTOR plasmas using activation technique.

MeV particle loss measurements from fusion plasmas, in particular alpha particles, remain difficult in large fusion devices and further R&D is needed for ITER. This paper describes the first attempt to measure 3 MeV escaping fusion protons emitted from TEXTOR tokamak plasmas using activation technique. This technique was successfully demonstrated, initially, in 2006 on the JET tokamak. An ion camera equipped with a collimator and several types of activation detectors was installed inside the TEXTOR vacuum vessel to perform these measurements. After irradiation, the detectors were analyzed using ultra low level gamma-ray spectrometry at the HADES underground laboratory. 3 MeV escaping fusion protons were detected in larger number -~6 times more--compared to earlier measurements using this technique on JET. Another major progress was the reduction of the cooling time by a factor of 50, which made possible to detect radionuclides with half-life of less than 90 min.

A non-statistical atomic model for beam emission and motional Stark effect diagnostics in fusion plasmas.

In this work we analyze magnetic sublevel populations in a neutral beam penetrating a fusion plasma. The collisional-radiative model NOMAD was extended to include magnetic parabolic sublevels with principal quantum numbers n ≤ 10. The collisional parameters were calculated with the advanced atomic-orbital close coupling method and the Glauber approximation. The ionization by the induced electric field was also included in the model. The results of our calculations show significant deviations of the sublevel populations and, accordingly, line intensities of the σ and π components, from the statistical approximation. It is shown, for instance, that for a number of experimental conditions the total intensity of σ components is not equal to the total intensity of π components, which has a strong effect on determination of magnetic field and pitch angle in fusion devices. The results are presented for a wide range of plasma and beam parameters. The most significant deviations are observed for strong magnetic fields and high beam energies typical for the ITER plasma, where component intensity ratios may deviate by more than 20% from the statistical values.

A high etendue spectrometer suitable for core charge eXchange recombination spectroscopy on ITER.

A feasibility study for the use of core charge exchange recombination spectroscopy on ITER has shown that accurate measurements on the helium ash require a spectrometer with a high etendue of 1mm(2)sr to comply with the measurement requirements [S. Tugarinov et al., Rev. Sci. Instrum. 74, 2075 (2003)]. To this purpose such an instrument has been developed consisting of three separate wavelength channels (to measure simultaneously He/Be, C/Ne, and H/D/T together with the Doppler shifted direct emission of the diagnostic neutral beam, the beam emission (BES) signal), combining high dispersion (0.02 nm/pixel), sufficient resolution (0.2 nm), high efficiency (55%), and extended wavelength range (14 nm) at high etendue. The combined measurement of the BES along the same sightline within a third wavelength range provides the possibility for in situ calibration of the charge eXchange recombination spectroscopy signals. In addition, the option is included to use the same instrument for measurements of the fast fluctuations of the beam emission intensity up to 2 MHz, with the aim to study MHD activity.

Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibration.

Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities.

Neoplasias del intestino delgado / Small intestinal neoplasms

Small intestine tumors are infrequent lesions during the routine clinical practice. They appear sporadically, in association with genetic diseases (e.g familiar adenomatous polyposis or Peutz-Jeghers syndrome), or associated to chronic inflammatory diseases (e.g Crohn’s disease or celiac disease). Benign tumors of small intestine (e.g leiomyomas, lipomas, adenomas, hamartomas or desmoid tumors) are generally asymptomatic, and may show up with intussusception. Primary malignant small intestine tumors (e.g adenocarcinoma, leiomyosarcoma, carcinoid tumor and lymphoma), can appear with intestinal obstruction, jaundice, digestive bleeding or abdominal pain. Small intestine metastatic lesions can appear by nearness, peritoneal metastasis or by hematological way. This last dissemination type is infrequent and more typically of melanoma. Because of its low prevalence, unspecific symptomatology and relative inaccessibility by conventional endoscopy, the diagnostic of small intestine neoplasm is often made several months after the first symptoms. Enteroclysis is a useful imaging technique towards the small intestine neoplasm suspicion. The endoscopic capsule and enteroscopy are actually the best diagnostic and therapeutic methods for this type of neoplasm. The treatment depends in the type of neoplasm, being the tumoral resection the first-line therapy.

Los tumores de intestino delgado son lesiones infrecuentes en la práctica clínica habitual. Aparecen de forma esporádica en asociación con enfermedades genéticas (por ej., poliposis adenomatosa familiar o síndrome de Peutz-Jeghers), o bien asociados a enfermedades inflamatoria crónicas intestinales (por ej., enfermedad de Crohn o enfermedad celíaca). Los tumores benignos de intestino delgado (por ej., leiomiomas, lipomas, adenoma, hamartoma o tumor desmoide) son generalmente asintomáticos, pudiendomanifestarse con intususcepción. Los tumores malignos primarios de intestino delgado (por ej.,adenocarcinoma, leiomiosarcoma, carcinoide y linfoma), pueden presentarse con obstrucción intestinal, ictericia, sangramiento digestivo o dolor abdominal. Las lesiones metastásicas de intestino delgado pueden aparecer por contigüidad, metástasis peritoneal o por vía hematógena. Este último tipo de diseminación es infrecuente y más típico del melanoma. Debido a su baja prevalencia, sintomatología inespecífica y relativa inaccesibilidad por endoscopía convencional, el diagnóstico de las neoplasias de intestino delgado es realizado a menudo varios meses después de iniciado los síntomas. La enteroclisis es una técnica de imagen útil frente a la sospecha de neoplasia de intestino delgado. La cápsula endoscópica y la enteroscopía son los métodos actualmente de mayor rendimiento para el diagnóstico y eventual terapia de este tipo de neoplasias. El tratamiento depende del tipo de neoplasia, siendo la resección tumoral la terapia de primera línea.

First results from the modular multi-channel dispersion interferometer at the TEXTOR tokamak.

At the TEXTOR tokamak in Jülich, Germany, a modular dispersion interferometer was installed and operated for the first time. Equipped with four lines of sight, the line-integrated density could be measured in parallel at different major radii with a resolution of better than 3 × 10(17) m(-2). This paper will describe the setup and show the first measurement results. Among others, it was possible to detect the evolution of a disruption with a time resolution of 4 µs. The movement of the runaway beam following the disruption could be resolved spatially and temporarily.

Diagnostics design for steady-state operation of the Wendelstein 7-X stellarator.

The status of the diagnostic developments for the quasistationary operable stellarator Wendelstein 7-X (maximum pulse length of 30 min at 10 MW ECRH heating at 140 GHz) will be reported on. Significant emphasis is being given to the issue of ECRH stray radiation shielding of in-vessel diagnostic components, which will be critical at high density operation requiring O2 and OXB heating.

Development of two-channel prototype ITER vacuum ultraviolet spectrometer with back-illuminated charge-coupled device and microchannel plate detectors.

A vacuum ultraviolet (VUV) spectrometer of a five-channel spectral system is designed for ITER main plasma impurity measurement. To develop and verify the system design, a two-channel prototype system is fabricated with No. 3 (14.4-31.8 nm) and No. 4 (29.0-60.0 nm) among the five channels. The optical system consists of a collimating mirror to collect the light from source to slit, two holographic diffraction gratings with toroidal geometry, and two different electronic detectors. For the test of the prototype system, a hollow cathode lamp is used as a light source. To find the appropriate detector for ITER VUV system, two kinds of detectors of the back-illuminated charge-coupled device and the microchannel plate electron multiplier are tested, and their performance has been investigated.

Development of a multichannel dispersion interferometer at TEXTOR.

The design and main characteristics of 14-channel dispersion interferometer for plasma profile measurement and control in TEXTOR tokamak are presented. The diagnostic is engineered on the basis of modular concept, the 10.6 microm CO(2) laser source and all optical and mechanical elements of each module are arranged in a compact housing. A set of mirrors and retroreflectors inside the TEXTOR vacuum vessel provides full coverage of the torus cross section with 12 vertical and two diagonal lines of sight, no rigid frame for vibration isolation is required. Results of testing of the single-channel prototype diagnostic and the pilot module of the multichannel dispersion interferometer are presented.

Validation of the ITER CXRS design by tests on TEXTOR.

The charge exchange recombination spectroscopy system (CXRS) for ITER is designed to measure the core helium concentration, and in addition, profiles of ion temperature and rotation. This highly demanding task, due to the huge background radiation (bremsstrahlung) and the high attenuation of the dedicated diagnostic neutral beam, requires high throughput spectrometers with high resolution. On TEXTOR, a CXRS system has been developed with the aim to test the physics implications of these specifications. (i) A relevant spectrometer has been tested. (ii) A method to determine the helium concentrations from the CXRS intensity, using the beam emission has been evaluated. A 20% discrepancy in beam emission was revealed. (iii) The determination of the magnetic pitch angle by the ratio of Balmer lines showed qualitatively the right behavior, although the accuracy was limited by the polarization sensitivity of the first mirror. (iv) The simulation code developed for the prediction of the CXRS spectra was quantitatively confronted with experimental data.

Review of atomic data needs for active charge-exchange spectroscopy on ITER.

The quantitative exploitation of active beam spectra is largely based on an advanced atomic modeling. Under the ITER operating conditions the penetration depth of a diagnostic beam into the plasma core crucially affects the intensities of spectral lines and hence the uncertainties of derived plasma parameters. A critical review of atomic data and an assessment of its error margins are, therefore, urgently needed. The aim of the present work is to verify the existing beam-stopping and beam-emission data for hydrogen beam in fusion plasmas. The agreement between the ADAS database and the present calculations is found to be within 5% for the beam-stopping data in a H-plasma. The calculation of beam attenuation in the presence of He-ash (4%) and Be ions (2%) demonstrates the agreement between the present data and the ADAS database within 10%. Finally, the maximum deviation of 15% is found only for beam-emission data at the electron density of 1x10(12)-2x10(12) cm(-3), which is significantly below the ITER density of 10(14) cm(-3).

Influence of the dynamic ergodic divertor on the density limit in TEXTOR.

A significant influence of the dynamic ergodic divertor (DED) on the density limit in TEXTOR has been found. In Ohmic discharges, where without DED detachment normally arises at the density limit, a MARFE (multifaceted asymmetric radiation from the edge) develops when the DED is operated in a static regime. The threshold of the MARFE onset in the neutral beam heated plasmas is increased by applying 1 kHz ac DED at the high-field side. The theoretical predictions based on the parallel energy balance taking poloidal asymmetries into account agree well with the experimental observation.

Toroidal plasma rotation induced by the dynamic ergodic divertor in the TEXTOR tokamak.

The first results of the Dynamic Ergodic Divertor in TEXTOR, when operating in the m/n=3/1 mode configuration, are presented. The deeply penetrating external magnetic field perturbation of this configuration increases the toroidal plasma rotation. Staying below the excitation threshold for the m/n=2/1 tearing mode, this toroidal rotation is always in the direction of the plasma current, even if the toroidal projection of the rotating magnetic field perturbation is in the opposite direction. The observed toroidal rotation direction is consistent with a radial electric field, generated by an enhanced electron transport in the ergodic layers near the resonances of the perturbation. This is an effect different from theoretical predictions, which assume a direct coupling between rotating perturbation and plasma to be the dominant effect of momentum transfer.