TY - JOUR
T1 - Multilayer mirror and foil filter AXUV diode arrays on CDX-U spherical torus
AU - Soukhanovskii, V. A.
AU - Stutman, D.
AU - Iovea, M.
AU - Finkenthal, M.
AU - Moos, H. W.
AU - Munsat, T.
AU - Jones, B.
AU - Hoffman, D.
AU - Kaita, R.
AU - Majeski, R.
PY - 2001/1
Y1 - 2001/1
N2 - Recent upgrades to CDX-U spherical torus diagnostics include two 10-channel AXUV diode arrays. The multilayer mirror (MLM) array measures the λ 150 O VI brightness profile in the poloidal plane using the Mo/B4C synthetic multilayer structures as dispersive elements. The foil filter array has a tangential view and is equipped with interchangeable clear aperture, beryllium and titanium filters. This allows measurements of radiated power, O VI or C V radial distributions, respectively. The O VI and C V emissivity and the radiated power profiles are highly peaked. A Neoclassical impurity accumulation mechanism is considered as an explanation. For radiated power measurements in the Te ≤ 100 eV plasmas, photon energy dependent corrections must be used in order to account for nonlinear AXUV sensitivity in the range Ephot≤20 eV. The arrays are also used for characterization of resistive MHD phenomena, such as the low m modes, saw-tooth oscillations and internal reconnection events. Based on the successful operation of the diagnostics, a new ultra soft x-ray multilayer mirror diode AXUV diode array monitoring the 34 Å emissivity distribution of C VI will be built and installed on the National Spherical Torus Experiment.
AB - Recent upgrades to CDX-U spherical torus diagnostics include two 10-channel AXUV diode arrays. The multilayer mirror (MLM) array measures the λ 150 O VI brightness profile in the poloidal plane using the Mo/B4C synthetic multilayer structures as dispersive elements. The foil filter array has a tangential view and is equipped with interchangeable clear aperture, beryllium and titanium filters. This allows measurements of radiated power, O VI or C V radial distributions, respectively. The O VI and C V emissivity and the radiated power profiles are highly peaked. A Neoclassical impurity accumulation mechanism is considered as an explanation. For radiated power measurements in the Te ≤ 100 eV plasmas, photon energy dependent corrections must be used in order to account for nonlinear AXUV sensitivity in the range Ephot≤20 eV. The arrays are also used for characterization of resistive MHD phenomena, such as the low m modes, saw-tooth oscillations and internal reconnection events. Based on the successful operation of the diagnostics, a new ultra soft x-ray multilayer mirror diode AXUV diode array monitoring the 34 Å emissivity distribution of C VI will be built and installed on the National Spherical Torus Experiment.
UR - http://www.scopus.com/inward/record.url?scp=0001017035&partnerID=8YFLogxK
U2 - 10.1063/1.1323254
DO - 10.1063/1.1323254
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AN - SCOPUS:0001017035
SN - 0034-6748
VL - 72
SP - 737
EP - 741
JO - Review of Scientific Instruments
JF - Review of Scientific Instruments
IS - 1 II
ER -