Bosonic superweakly interacting massive particles (super-WIMPs) are a candidate for warm dark matter. With the absorption of such a boson by a xenon atom these dark matter candidates would deposit an ...energy equivalent to their rest mass in the detector. This is the first direct detection experiment exploring the vector super-WIMPs in the mass range between 40 and 120 keV. Using 165.9 days of data no significant excess above background was observed in the fiducial mass of 41 kg. The present limit for the vector super-WIMPs excludes the possibility that such particles constitute all of dark matter. The absence of a signal also provides the most stringent direct constraint on the coupling constant of pseudoscalar super-WIMPs to electrons. The unprecedented sensitivity was achieved exploiting the low background at a level \(10^{-4}\) kg\(^{-1}\)keV\(_{ee}^{-1}\)day\(^{-1}\) in the detector.
A search for inelastic scattering of Weakly Interacting Massive Particles (WIMPs) on the isotope \(^{129}\)Xe was done in data taken with the single phase liquid xenon detector XMASS at the Kamioka ...Observatory. Using a restricted volume containing 41 kg of LXe at the very center of our detector we observed no significant excess of events in 165.9 days of data. Our background reduction allowed us to derive our limits without explicitly subtracting the remaining events which are compatible with background expectations and derive for e.g. a 50 GeV WIMP an upper limit for its inelastic cross section on \(^{129}\)Xe nuclei of 3.2 pb at the 90% confidence level.
XMASS, a low-background, large liquid-xenon detector, was used to search for solar axions that would be produced by bremsstrahlung and Compton effects in the Sun. With an exposure of 5.6ton days of ...liquid xenon, the model-independent limit on the coupling for mass \(\ll\) 1keV is \(|g_{aee}|< 5.4\times 10^{-11}\) (90% C.L.), which is a factor of two stronger than the existing experimental limit. The bounds on the axion masses for the DFSZ and KSVZ axion models are 1.9 and 250eV, respectively. In the mass range of 10-40keV, this study produced the most stringent limit, which is better than that previously derived from astrophysical arguments regarding the Sun to date.
A search for light dark matter using low-threshold data from the single phase liquid xenon scintillation detector XMASS, has been conducted. Using the entire 835 kg inner volume as target, the ...analysis threshold can be lowered to 0.3 keVee (electron-equivalent) to search for light dark matter. With low-threshold data corresponding to a 5591.4 kg\(\cdot\)day exposure of the detector and without discriminating between nuclear-recoil and electronic events, XMASS excludes part of the parameter space favored by other experiments.
The XMASS project aims to detect dark matter, pp and \(^{7}\)Be solar neutrinos, and neutrinoless double beta decay using ultra pure liquid xenon. The first phase of the XMASS experiment searches for ...dark matter. In this paper, we describe the XMASS detector in detail, including its configuration, data acquisition equipment and calibration system.
The automatic maximum level control scheme, which automatically selects the maximum power channel as the control channel and keeps its maximum power constant, is the most attractive candidate among ...gain control techniques applicable to wavelength-division-multiplexed linear repeaters. The design guidelines of this scheme are presented. The power transient response and bit-error-rate performance of the remaining channels during changes in the number of channels are measured in cascades of four repeaters. It is experimentally confirmed that power excursions and power penalties at the bit-error rate of 10/sup -9/ can be suppressed to less than 0.7 dB and less than 0.3 dB, respectively, even when seven out of eight channels are dropped within 1 μs.
The concept of a dynamic gain control method that automatically selects the maximum signal power and keeps it constant is described. This method can cope with not only changes in the number of ...channels, but also signal power fluctuations. No specific control channel is needed and gain control is active as long as just one signal channel is present. This method's feasibility is confirmed by eight-channel WDM power transient measurements.
Modular cross-connect system for WDM optical-path networks Ishida, O; Takachio, N; Sato, K
11th International Conference on Integrated Optics and Optical Fibre Communications. 23rd European Conference on Optical Communications IOOC-ECOC97,
1997
Conference Proceeding
Modular implementation of a cross-connect system based on the broadcast-and-select principle is proposed due to its built-in signal monitoring ability. A novel module configuration is demonstrated ...using integrated silica-waveguide technologies. In this paper we analyze modular cross-connect node architectures to examine their maintainability. We highlight the broadcast-and-select architecture with built-in signal monitoring, and demonstrate a novel configuration for the module.
Summary form only given. In this paper, we propose a novel gain control method that does not require any extra channel. We show the proposed gain control method. An optical repeater consists of a ...two-stage EDFA with automatic gain control (AGC) and a variable optical attenuator has been proposed as a low noise and wide dynamic range EDFA.
