The Next Generation BLAST Experiment Galitzki, Nicholas; Ade, Peter A. R; Angilè, Francesco E ...
Journal of Astronomical Instrumentation,
11/2014, Letnik:
3, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was a suborbital experiment designed to map magnetic fields in order to study their role in star formation ...processes. BLASTPol made detailed polarization maps of a number of molecular clouds during its successful flights from Antarctica in 2010 and 2012. We present the next-generation BLASTPol instrument (BLAST-TNG) that will build off the success of the previous experiment and continue its role as a unique instrument and a test bed for new technologies. With a 16-fold increase in mapping speed, BLAST-TNG will make larger and deeper maps. Major improvements include a 2.5-m carbon fiber mirror that is 40% wider than the BLASTPol mirror and ~3000 polarization sensitive detectors. BLAST-TNG will observe in three bands at 250, 350, and 500 μm. The telescope will serve as a pathfinder project for microwave kinetic inductance detector (MKID) technology, as applied to feedhorn-coupled submillimeter detector arrays. The liquid helium cooled cryostat will have a 28-day hold time and will utilize a closed-cycle 3He refrigerator to cool the detector arrays to 270 mK. This will enable a detailed mapping of more targets with higher polarization resolution than any other submillimeter experiment to date. BLAST-TNG will also be the first balloon-borne telescope to offer shared risk observing time to the community. This paper outlines the motivation for the project and the instrumental design.
We report the results of an experimental search for ultralight axionlike dark matter in the mass range 162-166 neV. The detection scheme of our Cosmic Axion Spin Precession Experiment is based on a ...precision measurement of ^{207}Pb solid-state nuclear magnetic resonance in a polarized ferroelectric crystal. Axionlike dark matter can exert an oscillating torque on ^{207}Pb nuclear spins via the electric dipole moment coupling g_{d} or via the gradient coupling g_{aNN}. We calibrate the detector and characterize the excitation spectrum and relaxation parameters of the nuclear spin ensemble with pulsed magnetic resonance measurements in a 4.4 T magnetic field. We sweep the magnetic field near this value and search for axionlike dark matter with Compton frequency within a 1 MHz band centered at 39.65 MHz. Our measurements place the upper bounds |g_{d}|<9.5×10^{-4} GeV^{-2} and |g_{aNN}|<2.8×10^{-1} GeV^{-1} (95% confidence level) in this frequency range. The constraint on g_{d} corresponds to an upper bound of 1.0×10^{-21} e cm on the amplitude of oscillations of the neutron electric dipole moment and 4.3×10^{-6} on the amplitude of oscillations of CP-violating θ parameter of quantum chromodynamics. Our results demonstrate the feasibility of using solid-state nuclear magnetic resonance to search for axionlike dark matter in the neV mass range.
Design of Cryogenic SiGe Low-Noise Amplifiers Weinreb, S.; Bardin, J.C.; Mani, H.
IEEE transactions on microwave theory and techniques,
11/2007, Letnik:
55, Številka:
11
Journal Article
Recenzirano
Odprti dostop
This paper describes a method for designing cryogenic silicon-germanium (SiGe) transistor low-noise amplifiers and reports record microwave noise temperature, i.e., 2 K, measured at the module ...connector interface with a 50-Omega generator. A theory for the relevant noise sources in the transistor is derived from first principles to give the minimum possible noise temperature and optimum generator impedance in terms of dc measured current gain and transconductance. These measured dc quantities are then reported for an IBM SiGe BiCMOS-8HP transistor at temperatures from 295 to 15 K. The measured and modeled noise and gain for both a single-and two-transistor cascode amplifier in the 0.2-3-GHz range are then presented. The noise model is then combined with the transistor equivalent-circuit elements in a circuit simulator and the noise in the frequency range up to 20 GHz is compared with that of a typical InP HEMT.
This paper presents a compact broadband cryogenic low noise amplifier (LNA) with simultaneous noise and power matching with transformer-based feedback. The LNA is composed of an input impedance ...transforming network and three-stage amplifiers to achieve simultaneous broadband low-noise and power matching. The first stage is a cascode amplifier with a drain source-coupled transformer. The second stage is a current-reuse broadband amplifier, and the third stage is an inductive-peaking cascode common-source amplifier. The LNA is packaged in a custom chassis and measured at 300K and 16K. At 300K probing measurement, the LNA achieves minimum noise Fig. of 1.42dB and S11< -10dB from 3.6-8.2 GHz with 34dB-35.9dB gain. The overall group delay is less than 0.3ns and IIP3 is ≥ -6dBm across the frequency range. At 16K, the LNA achieves a minimum noise Fig. (NF) of 0.065dB and NF < 0.3dB from 4.2-9.2 GHz with 31.4dB-34.7dB gain.
We present the performance of a superconducting nanowire that can be operated in two detection modes: (i) as a kinetic inductance detector (KID) or (ii) as a single-photon detector (SPD). Two ...superconducting nanowires developed for use as single-photon detectors (SNSPDs) are embedded as the inductive (L) component in resonant inductor/capacitor (LC) circuits coupled to a microwave transmission line. The capacitors are low loss commercial chip capacitors and limit the internal quality factor of the resonators to approximately
Q
i
=
170
. The resonator quality factor,
Q
r
≃
23
, is dominated by the coupling to the feedline and limits the detection bandwidth to on the order of 1 MHz. When operated in KID mode, the detectors are AC biased with tones at their resonant frequencies of 45.85 and 91.81 MHz. In the low-bias, standard KID mode, a single photon produces a hot spot that does not turn an entire section of the line normal but only increases the kinetic inductance. In the high-bias, critical KID mode, a photon event turns a section of the line normal and the resonance is destroyed until the normal region is dissipated. When operated as an SPD in Geiger mode, the resonators are DC biased through cryogenic bias tees and each photon produces a sharp voltage step followed by a ringdown signal at the resonant frequency of the detector which is converted to a standard pulse with an envelope detector. We show that AC biasing in the critical KID mode is inferior to the sensitivity achieved in DC-biased SPD mode due to the small fraction of time spent near the critical current with an AC bias.
Ali CMB Polarization Telescope (AliCPT) is the first Cosmic Microwave Background (CMB) polarimeter with a large focal plane camera to be deployed in the Northern Hemisphere, in the Tibetan Plateau. ...Here we present the design of a dichroic (90/150 GHz) focal plane camera capable of hosting up to 32,376 Transition-Edge Sensor (TES) bolometers operating from a base temperature of 280 mK. Detectors are fabricated as monolithic arrays of 1,704 feedhorn-coupled and polarization-sensitive TES bolometers that are packaged in independent modules and read out with a microwave multiplexing architecture. A custom RFSoC-based system manages the multiplexing readout. Prototype AliCPT pixels have been fabricated and characterized, demonstrating passband performance within 2.5% of design and cross-polarization systematic sensitivity <inline-formula><tex-math notation="LaTeX">\leq</tex-math></inline-formula>2%.
PDF
