Kinetic Inductance Detectors and readout electronics for the OLIMPO experiment

Abstract

Kinetic Inductance Detectors (KIDs) are superconductive low-temperature detectors useful for astrophysics and particle physics. We have developed arrays of lumped elements KIDs (LEKIDs) sensitive to microwave photons, optimized for the four horn-coupled focal planes of the OLIMPO balloon-borne telescope, working in the spectral bands centered at 150 GHz, 250 GHz, 350 GHz, and 460 GHz. This is aimed at measuring the spectrum of the Sunyaev-Zel'dovich effect for a number of galaxy clusters, and will validate LEKIDs technology in a space-like environment. Our detectors are optimized for an intermediate background level, due to the presence of residual atmosphere and room-temperature optical system and they operate at a temperature of 0.3 K. The LEKID planar superconducting circuits are designed to resonate between 100 and 600 MHz, and to match the impedance of the feeding waveguides; the measured quality factors of the resonators are in the 10 4 − 10 5 range, and they have been tuned to obtain the needed dynamic range. The readout electronics is composed of a cold part, which includes a low noise amplifier, a dc-block, coaxial cables, and power attenuators; and a roomtemperature part, FPGA-based, including up and down-conversion microwave components (IQ modulator, IQ demodulator, amplifiers, bias tees, attenuators). In this contribution, we describe the optimization, fabrication, characterization and validation of the OLIMPO detector system.

DEMETRA: Suppression of the Relaxation Induced by Radioactivity in Superconducting Qubits

“…KIDs recently gained a lot of attention as they offer exquisite energy resolution and are naturally multiplexed in the frequency domain, enabling the realization of large arrays monitored with a few readout lines. For this reason, they are now subject of an intense R&D activity for applications in astrophysics [17][18][19][20][21][22][23], in X-ray spectroscopy [24,25], in the search for Dark Matter [26,27], in precision measurements of the coherent elastic neutrino-nucleus scattering [28] and in double-beta decay searches [29][30][31][32][33].…”

Millimetric Sardinia radio Telescope Receiver based on Array of Lumped elements kids

“…It is centered at 90 GHz with ∼ 25 GHz of bandwidth. The readout system is based on an FPGA, successfully used for OLIMPO [16].…”

In-Flight Performance of the LEKIDs of the OLIMPO Experiment

“…In addition, the OLIMPO detectors had to be designed to operate at 0.3 K and for a minimum detectable frequency of 135 GHz. These constraints determined the choice of aluminum 30 nm thick, for which we measured the critical temperature, T c = 1.31 K, the residual resistance ratio, RRR = 3.1, the sheet resistance, R s = 1.21 Ω/ , and the surface inductance, L s = 1.38 pH/ , [26,27]. Fig.…”

“…The bias/readout system is composed of two independent chains, each serving two detector arrays and based on one ROACH2 board, including a MUSIC DAC/ADC board, and analog microwave components as amplifiers, bias tees, IQ modulator, IQ demodulator and attenuators. These systems, together with the firmware and the client software, were developed, tuned and characterized on the ground and described in [27,30]. The power dissipation system of the bias/readout electronics was modified in order to allow the components to work nominally in the stratospheric environment, where the external pressure of about 3 mbar results in a drastic reduction of convective cooling with respect to the ground.…”