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We present the design and characterization of the polarbear experiment. polarbear will measure the polarization of the cosmic microwave background (CMB) on angular scales ranging from the experiment's 3.5′ beam size to several degrees. The experiment utilizes a unique focal plane of 1,274 antenna-coupled, polarization sensitive TES bolometers cooled to 250 milliKelvin. Employing this focal plane along with stringent control over systematic errors, polarbear has the sensitivity to detect the expected small scale B-mode signal due to gravitational lensing and search for the large scale B-mode signal from inflationary gravitational waves. polarbear was assembled for an engineering run in the Inyo Mountains of California in 2010 and was deployed in late 2011 to the Atacama Desert in Chile. An overview of the instrument is presented along with characterization results from observations in Chile. © 2012 SPIE.

Sophisticated front-end electronics are a key part of practically all modern radiation detector systems. This chapter introduces the basic principles and their implementation. Topics include signal acquisition, electronic noise, pulse shaping (analog and digital), and data readout techniques.

This paper describes the AC-coupled, single-sided, p-in-n silicon microstrip sensors used in the Semiconductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The sensor requirements, specifications and designs are discussed, together with the qualification and quality assurance procedures adopted for their production. The measured sensor performance is presented, both initially and after irradiation to the fluence anticipated after 10 years of LHC operation. The sensors are now successfully assembled within the detecting modules of the SCT, and the SCT tracker is completed and integrated within the ATLAS Inner Detector. Hamamatsu Photonics Ltd. supplied 92.2percent of the 15,392 installed sensors, with the remainder supplied by CiS.

The past quarter century has brought about a revolution in front-end electronics for large-scale detector systems. Custom integrated circuits specifically tailored to the requirements of large detector systems have provided unprecedented performance and enabled systems that once were deemed impossible. The evolution of integrated circuit readouts in strip detectors is summarized, the present status described, and challenges posed by the sLHC and ILC are discussed. Performance requirements increase, but key considerations remain as in the past: power dissipation, material, and services. Smaller CMOS feature sizes will not provide the required electronic noise at lower power, but will improve digital power efficiency. Significant improvements appear to be practical in more efficient power distribution. Enhanced digital electronics have provided powerful trigger processors that greatly improve the trigger efficiency. In data readout systems they also improve data throughput, while reducing power requirements. Concurrently with new developments in high energy physics, detector systems for cosmology and astrophysics have made great strides. As an example, a large-scale readout for superconducting bolometer arrays is described.

Imaging sensors and readout electronics have made tremendous strides in the past two decades. The application of modern semiconductor fabrication techniques and the introduction of customized monolithic integrated circuits have made large scale imaging systems routine in high energy physics. This technology is now finding its way into other areas, such as space missions, synchrotron light sources, and medical imaging. I review current developments and discuss the promise and limits of new technologies. Several detector systems are described as examples of future trends. The discussion emphasizes semiconductor detector systems, but I also include recent developments for large-scale superconducting detector arrays.

We describe the development of an antenna-coupled bolometer array for use in a Cosmic Microwave Background polarization experiment. Prototype single pixels using double-slot dipole antennas and integrated microstrip band defining filters have been built and tested. Preliminary results of optical testing and simulations are presented. A bolometer array design based on this pixel will also be shown and future plans for application of the technology will be discussed.

The development of planar fabrication techniques for superconducting transition-edge sensors has brought large-scale arrays of 1000 pixels or more to the realm of practicality. This raises the problem of reading out a large number of sensors with a tractable number of connections. A possible solution is frequency-domain multiplexing. I summarize basic principles, present various circuit topologies, and discuss design trade-offs, noise performance, cross-talk and dynamic range. The design of a practical device and its readout system is described with a discussion of fabrication issues, practical limits and future prospects.

An FPGA based digital signal processing (DSP) system for biasing and reading out multiplexed bolometric detectors for mm-wavelength telescopes is presented. This readout system is being deployed for balloon-borne and ground based cosmology experiments with the primary goal of measuring the signature of inflation with the Cosmic Microwave Background Radiation. The system consists of analog superconducting electronics running at 250 mK and 4 K, coupled to digital room temperature backend electronics described here. The digital electronics perform the real time functionality with DSP algorithms implemented in firmware. A soft embedded processor provides all of the slow housekeeping control and communications. Each board in the system synthesizes multi-frequency combs of 8 to 32 carriers in the MHz band to bias the detectors. After the carriers have been modulated with the sky-signal by the detectors, the same boards digitize the comb directly. The carriers are mixed down to base-band and low pass filtered. The signal bandwidth of 0.050 Hz-100 Hz places extreme requirements on stability and requires powerful filtering techniques to recover the sky-signal from the MHz carriers. Index Terms--Digital signal processing, field programmable gate arrays, frequency division multiplexing, millimeter wave astronomy, real time systems, SQUIDs.

A frequency-multiplexed readout for arrays of high-resolution gamma detectors based on superconducting transition edge sensors (TESs) is described.

Frequency-domain readout multiplexer for transition-edge sensor (TES) bolometers is described and measurements of an eight-channel multiplexer are presented. The demodulated noise spectra from multiplexed sensors are found to show the expected white noise levels at frequencdcies above 200 mHz.

Low-dose-rate effects (LDREs) in bipolar technologies complicate the hardness assurance testing for high energy physics applications. The damage produced in the ICs in the real experiment can be underestimated if fast irradiations are carried out, while experiments done at the real dose rate are usually unpractical due to the still high total doses involved. In this work, the sensitivity to LDREs of the two bipolar technologies proposed for the ATLAS-SCT experiment in the LHC at CERN is evaluated, its magnitude measured at the total dose of interest for the transistors, and accelerated tests are performed, when necessary, on the actual ICs using high temperatures in order to mimic the effects of the low dose rate. One of the proposed technologies (DMILL) has been found free of LDREs, thus easing the radiation damage studies performed on it. The other one (CB2) suffers from LDRE. The effects have been measured for the individual devices. Experiments have been carried out to find the temperature that best mimics the LDRE at high dose rates. This temperature has been used in accelerated tests that have been performed on the chip fabricated with this technology in order to obtain the ionization damage that this IC will suffer under the real conditions. Index Terms--Bipolar integrated circuits, Bipolar transistors, ionisation damage, low-dose-rate effects (LDRE), radiation detectors, radiation effects.

The development of antenna-coupled bolometers using Transition-Edge Sensors (TES) for millimeter waves is reported. The results of the electrical and optical characterization of single bolometers pixels are presented.