A new receiver for the South Pole Telescope, SPT-3G, was deployed in early 2017 to map the cosmic microwave background at 95, 150, and 220 GHz with
∼
16,000 detectors, 10 times more than its ...predecessor SPTpol. The increase in detector count is made possible by lenslet-coupled trichroic polarization-sensitive pixels fabricated at Argonne National Laboratory, new 68
×
frequency-domain multiplexing readout electronics, and a higher-throughput optical design. The enhanced sensitivity of SPT-3G will enable a wide range of results including constraints on primordial B-mode polarization, measurements of gravitational lensing of the CMB, and a galaxy cluster survey. Here we present an overview of the instrument and its science objectives, highlighting its measured performance and plans for the upcoming 2018 observing season.
The third-generation South Pole Telescope camera is designed to measure the cosmic microwave background across three frequency bands (centered at 95, 150 and 220 GHz) with
∼
16,000 transition-edge ...sensor (TES) bolometers. Each multichroic array element on a detector wafer has a broadband sinuous antenna that couples power to six TESs, one for each of the three observing bands and both polarizations, via lumped element filters. Ten detector wafers populate the detector array, which is coupled to the sky via a large-aperture optical system. Here we present the frequency band characterization with Fourier transform spectroscopy, measurements of optical time constants, beam properties, and optical and polarization efficiencies of the detector array. The detectors have frequency bands consistent with our simulations and have high average optical efficiency which is 86, 77 and 66% for the 95, 150 and 220 GHz detectors. The time constants of the detectors are mostly between 0.5 and 5 ms. The beam is round with the correct size, and the polarization efficiency is more than 90% for most of the bolometers.
The South Pole Telescope third-generation (SPT-3G) receiver was installed during the austral summer of 2016–2017. It is designed to measure the cosmic microwave background across three frequency ...bands centered at 95, 150, and 220 GHz. The SPT-3G receiver has ten focal plane modules, each with 269 pixels. Each pixel features a broadband sinuous antenna coupled to a niobium microstrip transmission line. In-line filters define the desired band-passes before the signal is coupled to six bolometers with Ti/Au/Ti/Au transition edge sensors (three bands
×
two polarizations). In total, the SPT-3G receiver is composed of 16,000 detectors, which are read out using a 68
×
frequency-domain multiplexing scheme. In this paper, we present the process employed in fabricating the detector arrays.
The third-generation upgrade to the receiver on the South Pole Telescope, SPT-3G, was installed at the South Pole during the 2016–2017 austral summer to measure the polarization of the cosmic ...microwave background. Increasing the number of detectors by a factor of 10 to
∼
16
,
000
required the multiplexing factor to increase to 68 and the bandwidth of the frequency-division readout electronics to span 1.6–5.2 MHz. This increase necessitates low-thermal conductance, low-inductance cryogenic wiring. Our cold readout system consists of planar thin-film aluminum inductive–capacitive resonators, wired in series with the detectors, summed together, and connected to 4K SQUIDs by
10
-
μ
m
-thick niobium–titanium (NbTi) broadside-coupled striplines. Here, we present an overview of the cold readout electronics for SPT-3G, including assembly details and characterization of electrical and thermal properties of the system. We report, for the NbTi striplines, values of
R
≤
10
-
4
Ω
,
L
=
21
±
1
nH
, and
C
=
1.47
±
.
02
nF
. Additionally, the striplines’ thermal conductivity is described by
k
A
=
6.0
±
0.3
T
0.92
±
0.04
μ
W
mm
K
-
1
. Finally, we provide projections for cross talk induced by parasitic impedances from the stripline and find that the median value of percentage cross talk from leakage current is 0.22 and
0.09
%
from wiring impedance.
We have developed superconducting Ti transition-edge sensors with Au protection layers on the top and bottom for the South Pole Telescope’s third-generation receiver (a cosmic microwave background ...polarimeter, due to be upgraded this austral summer of 2017/2018). The base Au layer (deposited on a thin Ti glue layer) isolates the Ti from any substrate effects; the top Au layer protects the Ti from oxidation during processing and subsequent use of the sensors. We control the transition temperature and normal resistance of the sensors by varying the sensor width and the relative thicknesses of the Ti and Au layers. The transition temperature is roughly six times more sensitive to the thickness of the base Au layer than to that of the top Au layer. The normal resistance is inversely proportional to sensor width for any given film configuration. For widths greater than five micrometers, the critical temperature is independent of width.
During the austral summer of 2016–2017, the third-generation camera, SPT-3G, was installed on the South Pole Telescope, increasing the detector count in the focal plane by an order of magnitude ...relative to the previous generation. Designed to map the polarization of the cosmic microwave background, SPT-3G contains ten 6
′
′
-hexagonal modules of detectors, each with 269 trichroic and dual-polarization pixels, read out using 68
×
frequency-domain multiplexing. Here we discuss design, assembly, and layout of the modules, as well as early performance characterization of the first-year array, including yield and detector properties.
The primary objective of the review is to assess the potential of lymphatic-targeted drug delivery systems, with a particular emphasis on their role in tumour therapy and vaccination efficacy.
The ...lymphatic system's crucial functions in maintaining bodily equilibrium, regulating metabolism, and orchestrating immune responses make it an ideal target for drug delivery. Lymph nodes, being primary sites for tumour metastasis, underscore the importance of targeting the lymphatic system for effective treatment.
Nanotechnologies and innovative biomaterials have facilitated the development of lymphatic-targeted drug carriers, leveraging endogenous macromolecules to enhance drug delivery efficiency. Various systems such as liposomes, micelles, inorganic nanomaterials, hydrogels, and nano-capsules demonstrate significant potential for delivering drugs to the lymphatic system.
Understanding the physiological functions of the lymphatic system and its involvement in diseases underscores the promise of targeted drug delivery in improving treatment outcomes. The strategic targeting of the lymphatic system presents opportunities to enhance patient prognosis and advance therapeutic interventions across various medical contexts, indicating the importance of ongoing research and development in this area.
In this work, we have measured the properties of membrane-suspended bolometer thermal links and microstrip transmission lines in the transition-edge sensor arrays for the third-generation camera for ...South Pole Telescope (SPT-3G). A promising technique for controlling the end point of the release etch that defines the thermal link has been developed. We have also evaluated the microstrip loss in our detectors by measuring the optical efficiency of detectors with different lengths of microstrip line. The loss tangent is sufficiently low for the use in multi-chronic pixels for cosmic microwave background instruments like SPT-3G.
The Coulomb gap observed in tunneling between parallel two-dimensional electron systems, each at half-filling of the lowest Landau level, is found to depend sensitively on the presence of an in-plane ...magnetic field. Especially at low electron density, the width of the Coulomb gap at first increases sharply with in-plane field, but then abruptly levels off. This behavior appears to coincide with the known transition from partial to complete spin polarization of the half-filled lowest Landau level. The tunneling gap therefore opens a window onto the spin configuration of two-dimensional electron systems at high magnetic field.
Abstract
High angular resolution cosmic microwave background experiments provide a unique opportunity to conduct a survey of time-variable sources at millimeter wavelengths, a population that has ...primarily been understood through follow-up measurements of detections in other bands. Here we report the first results of an astronomical transient survey with the South Pole Telescope (SPT) using the SPT-3G camera to observe 1500 deg
2
of the southern sky. The observations took place from 2020 March to November in three bands centered at 95, 150, and 220 GHz. This survey yielded the detection of 15 transient events from sources not previously detected by the SPT. The majority are associated with variable stars of different types, expanding the number of such detected flares by more than a factor of two. The stellar flares are unpolarized and bright, in some cases exceeding 1 Jy, and have durations from a few minutes to several hours. Another population of detected events last for 2–3 weeks and appear to be extragalactic in origin. Though data availability at other wavelengths is limited, we find evidence for concurrent optical activity for two of the stellar flares. Future data from SPT-3G and forthcoming instruments will provide real-time detection of millimeter-wave transients on timescales of minutes to months.
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