Ultra-sensitive Transition-Edge Sensors for the Background Limited Infrared/Sub-mm Spectrograph (BLISS)

We report progress in fabricating ultra-sensitive superconducting transition-edge sensors (TESs) for BLISS. BLISS is a suite of grating spectrometers covering 35–433?μm with R～700 cooled to 50?mK that is proposed to fly on the Japanese space telescope SPICA. The detector arrays for BLISS are TES bolometers readout with a time domain SQUID multiplexer. The required noise equivalent power (NEP) for BLISS is NEP=10^?19?W/Hz^1/2 with an ultimate goal of NEP=5×10^?20?W/Hz^1/2 to achieve background limited noise performance. The required and goal response times are τ=150?ms and τ=50?ms respectively to achieve the NEP at the required and goal optical chop frequency 1–5?Hz. We measured prototype BLISS arrays and have achieved NEP=6×10^?18?W/Hz^1/2 and τ=1.4?ms with a Ti TES (T _C=565?mK) and NEP～2.5×10^?19?W/Hz^1/2 and τ～4.5?ms with an Ir TES (T _C=130?mK). Dark power for these tests is estimated at 1–5?fW.     

Electrical Properties of Background-Limited Membrane-Isolation Transition-Edge Sensing Bolometers for Far-IR/Submillimeter Direct-Detection Spectroscopy

We built and measured the electrical properties of membrane-isolation transition-edge sensing bolometers (TESs) suitable for background-limited far-IR/submillimeter direct-detection spectroscopy. Each TES consists of a Mo/Au bilayer patterned onto a suspended, thermally isolated absorber that is connected to the substrate through four Si _x N _y beams deposited by low pressure chemical vapor deposition (LPCVD). We fabricated TESs with straight and meander support beams. The dimensions of the meander (straight) support beams are 700 μm (700 μm) long by 0.25 μm (0.5 μm) thick by 0.35 μm (0.5 μm) wide. We measured I–V characteristics for these TESs and determined that the thermal conductance G equals 72 fW/K (straight) and 19 fW/K (meander) for our best devices. The thermal conductance exhibits a T ^1/2 dependence with temperature which is evidence of effective elastic scattering of the acoustic phonon modes. The transition temperatures T _c for the same TESs are T _c =137 mK (straight) and T _c =71 mK (meander). If we assume the TESs are temperature-fluctuation noise limited, then the derived noise equivalent power (NEP) equals 1.9×10⁻¹⁹ W/Hz^1/2 (straight) and 6.1×10⁻²⁰ W/Hz^1/2 (meander), using our measured values for G and T _c . The meander-beam TES has a derived NEP that is close to two orders of magnitude lower than the state-of-the-art. Finally, we measured an effective time constant τ of about 300 ms (straight) and 400 ms (meander) using electrical and optical pulses. These values for the NEP and τ for the meander-beam TES meet the requirements for the Background-Limited far-IR/Submillimeter Spectrograph (BLISS), a proposed NASA instrument.      

Low-Amplitude-Noise Laser for AURIGA Detector Optical Readout

We implemented a laser system to be used in an optical transduction chain for the gravitational-wave bar detector AURIGA (Antenna Ultracriogenica Risonante per l'Indagine Gravitazionale Astronomica; Ultracryogenic Resonant Antenna for Astronomical Gravitational Investigation). This system is based on a Nd:YAG laser and includes quantum-limited power stabilization in the acoustic range, deep phase modulation and near-quantum-limited rf detection for locking onto optical cavities, and coupling to a single-mode polarization-maintaining optical fiber without deterioration of performance. Such a system has wide applications in optical metrology.     

Interfacing of a Coordinate-Sensitive Detector Based on Charge-Coupled Devices for Recording Ions with a Portable Static Mass Spectrograph

An IDS 2030 IonCCD coordinate-sensitive detector (Analytical/CMS Field Products) is interfaced with a small-sized mass spectrograph developed at the Ioffe Physical Technical Institute, Russian Academy of Sciences. The measurement data obtained with the mass spectrograph using an IonCCD detector and a Magnum-5901-37029PS channel secondary electron multiplier (Photonics USA Inc., United States) are compared. The results of measurements are discussed, and the prospects for using the IonCCD coupled with a microchannel plate are assessed.     

Current Sensitivity Enhancement of a Quasi-One-Junction SQUID Comparator as an Input Circuit of SFQ Readout Circuit for a Superconducting Detector

We evaluated the current sensitivity of a quasi-one-junction SQUID (QOS) comparator with an input transformer at 4.2 K. A comparator based on a QOS is promising for constructing the single flux quantum (SFQ) readout circuits of an array system of multiple superconducting detectors.The QOS comparator is made of three Nb/AlO \(_x\) /Nb Josephson junctions, senses an output signal of a superconductor detector, and generates the SFQ pulses.There are strong demands for enhancing the current sensitivity of the QOS comparator because an output current from superconducting detector typically remains at the magnitude of a few \(\upmu \) A. We fabricated the QOS comparator with an input transformer using AIST Standard Process 2, where the critical current density of the Josephson junctions is chosen as high as 2.5 kA/cm \(^{2}\) . We designed the input transformer to enhance the current sensitivity under the conditions of 200  \(\upmu \) m  \(\times \)  200  \(\upmu \) m in size and 20:1 in turn ratio. Consequently, we succeeded in reducing a gray zone width of the comparator, and achieved the current sensitivity of 400 nA at 4.2 K in the low frequency range.     

Geant4 Simulations of the SuperCDMS iZIP Detector Charge Carrier Propagation and FET Readout

The SuperCDMS experiment aims to directly detect dark matter particles called WIMPs (weakly interacting massive particles). The detectors measure phonon and ionization energy due to nuclear and electron recoils from incident particles. The SuperCDMS Detector Monte Carlo group uses Geant4 to simulate electron-hole pairs ( \(e^-/h^+\) ) and low temperature phonons. We use these simulations in order to study energy deposition in the detectors. Phonons and electron-hole pairs are tracked in a crystal detector. Because of the band structure of the crystals, the electrons undergo oblique propagation. The charge electrodes on each side of the detector are biased at different voltages while the phonon sensors are grounded. This creates a nearly uniform electric field through the bulk of the detector, with a complex shape near the surfaces. The electric field is calculated from interpolating on a tetrahedral mesh. The resulting TES phonon readout, as well as the FET charge readout are simulated. To calculate the FET readout, the Shockley-Ramo theorem is applied to simulate the current in the FET. The goal of this paper is to describe the theory and implementation of calculating the electric field, performing the charge carrier propagation, and simulating the FET readout of the SuperCDMS detectors.     

The Detector System for the Stratospheric Kinetic Inductance Polarimeter (Skip)

The stratospheric kinetic inductance polarimeter is a proposed balloon-borne experiment designed to study the cosmic microwave background, the cosmic infrared background and Galactic dust emission by observing 1,133 deg \(^2\) of sky in the Northern Hemisphere with launches from Kiruna, Sweden. The instrument contains 2,317 single-polarization, horn-coupled, aluminum lumped-element kinetic inductance detectors (Lekids). The Lekids will be maintained at 100 mK with an adiabatic demagnetization refrigerator. The polarimeter operates in two configurations, one sensitive to a spectral band centered on 150 GHz and the other sensitive to 260 and 350 GHz bands. The detector readout system is based on the ROACH-1 board, and the detectors will be biased below 300 MHz. The detector array is fed by an F/2.4 crossed-Dragone telescope with a 500 mm aperture yielding a 15 arcmin FWHM beam at 150 GHz. To minimize detector loading and maximize sensitivity, the entire optical system will be cooled to 1 K. Linearly polarized sky signals will be modulated with a metal-mesh half-wave plate that is mounted at the telescope aperture and rotated by a superconducting magnetic bearing. The observation program consists of at least two, 5-day flights beginning with the 150 GHz observations.     

Software Architecture for a Virtual Environment for Nano Scale Assembly (VENSA)

A Virtual Environment (VE) uses multiple computer-generated media to let a user experience situations that are temporally and spatially prohibiting. The information flow between the user and the VE is bidirectional and the user can influence the environment. The software development of a VE requires orchestrating multiple peripherals and computers in a synchronized way in real time. Although a multitude of useful software components for VEs exists, many of these are packaged within a complex framework and can not be used separately. In this paper, an architecture is presented which is designed to let multiple frameworks work together while being shielded from the application program. This architecture, which is called the Virtual Environment for Nano Scale Assembly (VENSA), has been constructed for interfacing with an optical tweezers instrument for nanotechnology development. However, this approach can be generalized for most virtual environments. Through the use of VENSA, the programmer can rely on existing solutions and concentrate more on the application software design.     

位置敏感探测器定位分析和应用研究

位置敏感探测器是近几年问世的一种新型位置探测器,可直接用来测量角度、高度、距离及运动。本文论证了二维位置敏感探测器定位原理,导出了位置坐标的电流函数表达式,给出了相应的检测电路框图,提出了用位置敏感探测器进行人体三维运动测量的系统方案,并就信号的产生、提取及数据处理问题进行了讨论,最后估算了有关系统参数。     

Sub-Kelvin cooler configuration study for the Background Limited Infrared Submillimeter Spectrometer BLISS on SPICA

The Background Limited Infrared Submillimeter Spectrometer (BLISS) is an instrument proposed for the Japanese space borne telescope mission SPICA. The BLISS concept is a suite of grating spectrometers which combine to cover the 40-400 μm range at resolving power R∼700 with detector sensitivity approaching the natural photon background limits. To achieve the high sensitivity, the BLISS detectors require cooling to 50 mK, well below the 1.7 K cold stage provided on the SPICA spacecraft. We present a thermal architecture for BLISS that includes a thermal intercept stage actively cooled to a temperature in between the 1.7 K cold tip and the detector stage at 50 mK. This architecture requires, essentially, two coolers; one to cool the intercept stage from 1.7 K and one to cool the detectors from the intercept stage temperature to 50 mK. We compared several configurations of flight-heritage coolers to cool the intercept and detector stages. Of the various configurations studied, a continuous adiabatic demagnetization refrigerator (ADR) for each stage has the highest maturity, lowest heat dump at 1.7 K and total mass comparable to other approaches. Other options, such as a Herschel ³He sorption cooler-ADR hybrid and the recently demonstrated closed cycle version of the dilution cooler on Planck are also feasible for BLISS on SPICA.     

Bicell Pyroelectric Optical Detector Made from a Single LiNbO(3) Domain-Reversed Electret

Using electric-field poling at room temperature, we selectively reversed the direction of the spontaneous polarization in a 200-mum-thick, z-cut LiNbO(3) electret to produce a bicell pyroelectric detector. The detector required only a single set of electrodes, one electrode on the front surface and one on the back surface. Microphonic noise that is typical of monocell pyroelectric detectors is reduced in the present device. Our spatial uniformity data indicate that the optical response of one half of the bicell detector area was equal to and opposite the other half within 1.2%. The microphonic suppression of the bicell pyroelectric detector was less than -36 dB from 10 to 50 Hz and less than -118 dB at 35 Hz of that of a reference monocell pyroelectric detector. The substrate thickness is significantly greater than those of other domain-engineered pyroelectric detector designs and allows us to build practical, large-area detectors for radiometric applications.     

原子荧光光谱法测定进口大米中总砷含量的不确定度评定

根据GB/T5009.11-2003中"第一法氢化物原子荧光光度法"对大米中总砷的含量进行检测,并评定了检测结果的不确定度.评定发现最终不确定度来源主要来自于标准曲线引入的不确定度和仪器本身引入的不确定度.     

用于阴离子检测的聚苯胺电极

研究了聚苯胺电极在含不同阴离子的电解液中的氧化还原反应（掺杂－脱掺杂）以及在流动注射分析中该电极对阴离子的选择性和灵敏性。