In modern radio astronomy, one of the key technologies is to widen the frequency coverage of an instrument. The effects of higher-order modes on an instrument associated with wider bandwidths have ...been reported, which may degrade observation precision. It is important to quantify the higher-order propagation modes, though their power is too small to measure directly. Instead of the direct measurement of modes, we make an attempt to deduce them based on measurable radiation patterns. Assuming a linear system, whose radiated field is determined as a superposition of the mode coefficients in an instrument, we obtain a coefficient matrix connecting the modes and the radiated field and calculate the pseudo-inverse matrix. To investigate the accuracy of the proposed method, we demonstrate two cases with numerical simulations, axially-corrugated horn case and offset Cassegrain antenna case, and the effect of random errors on the precision. Both cases showed the deduced mode coefficients with a precision of 10e-6 with respect to the maximum mode amplitude and 10e-3 degrees in phase, respectively. The calculation errors were observed when the random errors were smaller than 0.01 percent of the maximum radiated field amplitude, which was a much lower level compared with measurement precision. The demonstrated method works independently of the details of a system. The method can quantify the propagation modes inside an instrument and will be applied to most of linear components and antennas, which leads to various applications such as diagnosis of feed alignment and higher-performance feed design.
The purpose of this study was to assess the efficacy and toxicity of definitive radiotherapy (RT) for the recurrence of epithelial ovarian cancer, which is limited to one or two gross regions, after ...complete remission had been achieved with aggressive front-line therapy. Twenty-seven patients were treated with definitive RT and were retrospectively analyzed. Their median tumor size was 3.0 cm. Twenty-six (96%) patients received external irradiation at a median total dose of 60 Gy, and a median daily dose of 2 Gy. Only two patients received intracavitary brachytherapy. Twenty (74%) of the 27 patients received systemic chemotherapy for the treatment of a limited recurrent tumor followed by definitive RT. Six (22%) of the patients received concurrent chemotherapy and seven (26%) of the patients also underwent regional hyperthermia during definitive RT. Twenty-two (82%) patients had an objective response (CR: 11, PR: 11). The 2-year overall survival, progression-free survival and local (in-field) control rates after RT were 53%, 39% and 96%, respectively. The toxicities were mild, no Grade 3 or higher toxicity was observed in any of the patients. The tumor size( < 3 cm), period between front-line therapy and RT (≥2 year) and objective tumor response (CR) were significant prognostic factors of the overall survival rate. In conclusion, definitive RT for limited recurrence of epithelial ovarian cancer achieves a better local control rate without severe toxicity, and it may therefore be a potentially effective modality for inducing long-term survival in selected patients.
Sensitivity Modeling for LiteBIRD Allys, E.; Arnold, K.; Auguste, D. ...
Journal of low temperature physics,
2023, Letnik:
211, Številka:
5-6
Journal Article
Recenzirano
Odprti dostop
LiteBIRD
is a future satellite mission designed to observe the polarization of the cosmic microwave background radiation in order to probe the inflationary universe.
LiteBIRD
is set to observe the ...sky using three telescopes with transition-edge sensor bolometers. In this work we estimated the LiteBIRD instrumental sensitivity using its current design. We estimated the detector noise due to the optical loadings using physical optics and ray-tracing simulations. The noise terms associated with thermal carrier and readout noise were modeled in the detector noise calculation. We calculated the observational sensitivities over fifteen bands designed for the LiteBIRD telescopes using assumed observation time efficiency.
Feedhorn- and orthomode transducer- (OMT) coupled transition edge sensor (TES) bolometers have been designed and micro-fabricated to meet the optical specifications of the LiteBIRD high frequency ...telescope (HFT) focal plane. We discuss the design and optical characterization of two LiteBIRD HFT detector types: dual-polarization, dual-frequency-band pixels with 195/280 GHz and 235/337 GHz band centers. Results show well-matched passbands between orthogonal polarization channels and frequency centers within 3% of the design values. The optical efficiency of each frequency channel is conservatively reported to be within the range 0.64
-
0.72, determined from the response to a cryogenic, temperature-controlled thermal source. These values are in good agreement with expectations and either exceed or are within 10% of the values used in the LiteBIRD sensitivity forecast. Lastly, we report a measurement of loss in Nb/SiN
x
/Nb microstrip at 100 mK and over the frequency range 200–350 GHz, which is comparable to values previously reported in the literature.
Surface charge distributions of disk type aluminas held between a backside electrode (alumina holder) and a needle electrode to be excited by an impulse voltage (rise time 64 /spl mu/s, wave tail 700 .../spl mu/s) were measured. The measurement of surface charge distribution on the whole surface area of alumina YSA998 and UHA99 after impulse voltage application revealed that the surface charging can be initiated either from the anode or from the cathode triple junction. The charging initiated from the anode triple junction (for positive polarity) produced positive charge at the anode region and the density is dependent on the applied voltage, while the charging initiated from the cathode triple junction region (for negative polarity) produced negative charge around the cathode region. For positive polarity, the critical values of charge density to the flashover for alumina YSA998 and UHA98 are 5.70 and 17.2 /spl mu/C/m/sup 2/, respectively.
We developed broadband anti-reflection coating using subwavelength structures on C-cut sapphire. We ablated sapphire using a femtosecond pulsed laser. We have developed a scanning strategy to make ...the deep structure. We successfully fabricated two saphire samples with arrays of the pyramidal structures over a machined diameter of 34.5 mm. The dimensions of the pyramid are a pitch of 0.54 mm and a height of 2.1 mm. The slope of the pyramid was fine tuned to be a bell shape, which could give better broadband anti-reflection performance compared to other shapes we investigated. The processing time is 10.5 hours for each sample. The number of the fabricated structures are more than 3000 for each samples, and we did not observe any loss of the structure due to the fabrication process. Transmittance measurements agreed with the predictions based on the measured structure shape and we achieved larger than 90% between 40 and 180 GHz. We will discuss the implication of this demonstrated performance in relation to mm-wave quasi-optical element, specifically in the context of astrophysical measurements of the cosmic microwave background radiation.
Recent developments of transition-edge sensors (TESs), based on extensive experience in ground-based experiments, have been making the sensor techniques mature enough for their application on future ...satellite CMB polarization experiments. LiteBIRD is in the most advanced phase among such future satellites, targeting its launch in Japanese Fiscal Year 2027 (2027FY) with JAXA's H3 rocket. It will accommodate more than 4000 TESs in focal planes of reflective low-frequency and refractive medium-and-high-frequency telescopes in order to detect a signature imprinted on the cosmic microwave background (CMB) by the primordial gravitational waves predicted in cosmic inflation. The total wide frequency coverage between 34GHz and 448GHz enables us to extract such weak spiral polarization patterns through the precise subtraction of our Galaxy's foreground emission by using spectral differences among CMB and foreground signals. Telescopes are cooled down to 5Kelvin for suppressing thermal noise and contain polarization modulators with transmissive half-wave plates at individual apertures for separating sky polarization signals from artificial polarization and for mitigating from instrumental 1/f noise. Passive cooling by using V-grooves supports active cooling with mechanical coolers as well as adiabatic demagnetization refrigerators. Sky observations from the second Sun-Earth Lagrangian point, L2, are planned for three years. An international collaboration between Japan, USA, Canada, and Europe is sharing various roles. In May 2019, the Institute of Space and Astronautical Science (ISAS), JAXA selected LiteBIRD as the strategic large mission No. 2.
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