Transition Edge Sensor Detectors Research Articles

Application of optimum digital filter based on genetic algorithms for transition edge sensor detector

We propose a new signal processing method to improve the energy resolution of superconducting tunnel junction X-ray detectors. An optimum FIR (Finite Impulse Response) filter design tool based on fast Fourier transform was developed using genetic algorithms. The fast Fourier transform is perhaps one of the most used algorithms today in the analysis and manipulation of digital or discrete data. The main feature of this tool is that it needs a minimum number of parameters to specify the FIR filter specifications. This tool was applied successfully on transition edge sensor detector.

Transition-Edge Sensors for Particle Induced X-ray Emission Measurements

In this paper we present a new measurement setup, where a transition-edge sensor detector array is used to detect X-rays in particle induced X-ray emission (PIXE) measurements with a 2 MeV proton beam. Transition-edge sensors offer orders of magnitude improvement in energy resolution compared to conventional silicon or germanium detectors, making it possible to recognize spectral lines in materials analysis that have previously been impossible to resolve, and to get chemical information from the elements. Our sensors are cooled to the operation temperature ( $$\sim $$ 65 mK) with a cryogen-free adiabatic demagnetization refrigerator, which houses a specially designed X-ray snout that has a vacuum tight window to couple in the radiation. For the best pixel, the measured instrumental energy resolution was 3.06 eV full width at half maximum at 5.9 keV. We discuss the current status of the project, benefits of transition-edge sensors when used in PIXE spectroscopy, and the results from the first measurements.

Design and Performance of Kilo-Pixel TES Arrays for ACTPol

ACTPol, a polarization sensitive receiver for the Atacama Cosmology Telescope, is designed to make sensitive maps of the cosmic microwave background anisotropies at arcminute scales and millimeter wavelengths by employing three arrays of superconducting transition edge sensor (TES) detectors. The ACTPol TES bolometers have a target superconducting transition temperature of 150 mK and will be cooled to a bath temperature of 100 mK with a dilution refrigerator enabling increased array sensitivity. Each array will consist of ~1000 TES detectors coupled to a micromachined silicon feedhorn stack via superconducting ortho-mode transducers and transmission lines. The superconducting detectors of the first ACTPol array have been characterized in their final receiver configuration with measurements of key TES parameters including the transition temperature, saturation power, and thermal conductance.

Development of hard X-ray and gamma-ray spectrometer using superconducting transition edge sensor

Abstract Superconducting transition edge sensors (TES) are used for high-resolution X-ray spectroscopy. In our group, we developed an Ir-TES and reported an energy resolution of 6.9 eV FWHM at 5.9 keV ( Kunieda et al., 2004 ). In this study, we have designed a new TES detector using a superconducting tin (Sn) absorber to detect high energy photons over 100 keV. The Sn absorber is coupled to an Ir/Au superconducting film which is deposited on an ultra-thin SiN membrane (500 nm thick) with a small amount of epoxy post (Stycast 2850FT) by handling with a flip-chip bonding machine. The measured energy resolution is 485 eV FWHM at 60 keV and is better than that of HPGe detector.

Prototype detector technology for the SCUBA-2 submillimetre bolometer array

This paper reports the latest design and the associated fabrication technology of the Mk II prototype infrared (IR) detector for the two 5120 pixel SCUBA-2 (submillimetre common user bolometer arry) instruments, which are to be mounted on the James Clerk Maxwell telescope (JCMT) in Hawaii. Progress is described on the design and the technology modules being developed for the new detector, which is based upon silicon micromachining. The two arrays of transition edge sensors (TES) are used to detect incoming radiation with wavelengths of 450 and 850 μ respectively and as the SCUBA-2 detector operates at about 100 mK, it consequently involves integration with low-temperature electronics and careful design of the associated interconnect. A key aspect of the connection between the TES detector and readout electronics is the use of indium flip-chip bumps, which become superconducting at cryogenic temperatures. The integration of nanoscale membranes and transition edge sensors together with microsystem technology enables SCUBA-2 to have of the order of 10 -17W (1 Hz bandwidth) sensitivity to incoming radiation.

Electronics for arrays of transition edge sensors using digital signal processing

Single-pixel transition-edge sensors (TES) are useful for a variety of applications requiring the detection of photons from sub-millimeter wavelengths to gamma rays. Arrays of TES's are required in the next-generation instruments to continue to be useful. We report on the development and performance of an electronics system used to readout and process signals from arrays of TES detectors. The system utilizes high-performance analog and digital electronics, and digital signal-processing. Because the system digitizes signals early in the signal processing chain, it is possible to implement a digital-feedback system to flux lock a SQUID amplifier and digitally process the detector (feedback) signal.