[Paper Review] Energy resolution and efficiency of phonon-mediated KIDs for light detection

L. Cardani, I. Colantoni+9 more|arXiv (Cornell University)|May 18, 2015

Superconducting and THz Device Technology3 citations

TL;DR

This paper presents a phonon-mediated Kinetic Inductance Detector (KID) prototype with four 40 nm aluminum resonators on a 2×2 cm² silicon chip, achieving an energy resolution of 154±7 eV and an efficiency of 18±2% when exposed to optical pulses and a ⁵⁷Co X-ray source, demonstrating its potential for large-area cryogenic light detection in rare-event searches.

ABSTRACT

The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like Dark Matter interactions or Neutrinoless Double Beta Decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm$^2$ are needed. For this reason, we are developing phonon-mediated detectors. In this paper we present the first results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2x2 cm$^2$ silicon chip. The detector, exposed to optical pulses and to a $^{57}$Co X-ray source, features an energy resolution of 154+-7 eV and an efficiency of (18+-2)%.

Motivation & Objective

• Develop large-area cryogenic light detectors for rare-event experiments such as Dark Matter and Neutrinoless Double Beta Decay.
• Address the challenge of coupling sensitive detectors to large bolometric crystals requiring active areas of several cm².
• Implement phonon-mediated energy transduction in Kinetic Inductance Detectors (KIDs) to enable efficient signal collection over large areas.
• Demonstrate energy resolution and detection efficiency suitable for next-generation bolometric experiments.
• Validate the performance of a prototype KID array with 40 nm aluminum resonators on a 2×2 cm² silicon substrate.

Proposed method

• Fabricate four 40 nm thick aluminum resonators patterned on a 2×2 cm² silicon chip to form a phonon-mediated KID array.
• Use optical pulses and a ⁵⁷Co X-ray source to calibrate and test detector response.
• Measure energy resolution by analyzing the full width at half maximum (FWHM) of the detected X-ray peak.
• Determine detection efficiency by comparing the number of detected events to the expected number from the source.
• Employ cryogenic operation to ensure low thermal noise and high sensitivity.
• Utilize multiplexed read-out of KIDs to enable scalable detection across large active areas.

Experimental results

Research questions

• RQ1 Can phonon-mediated KIDs achieve sufficient energy resolution for rare-event detection in large-area configurations?
• RQ2 What is the detection efficiency of a KID array with 40 nm aluminum resonators on a 2×2 cm² silicon substrate?
• RQ3 How does the energy resolution of the prototype compare to requirements for bolometric experiments?
• RQ4 To what extent can KIDs be scaled to large active areas while maintaining high sensitivity?
• RQ5 Can KIDs with phonon-mediated transduction efficiently detect low-energy photons from radioactive sources like ⁵⁷Co?

Key findings

• The prototype KID detector achieved an energy resolution of 154±7 eV, indicating high sensitivity to low-energy events.
• The detection efficiency was measured at 18±2%, demonstrating feasibility for coupling to large bolometric crystals.
• The detector's performance was validated using both optical pulses and a ⁵⁷Co X-ray source, confirming consistent response across different excitation types.
• The 40 nm aluminum resonators on the 2×2 cm² silicon substrate enabled effective phonon-mediated signal transduction.
• The results support the scalability of KID-based light detectors for large-area applications in rare-event physics.
• The combination of good energy resolution and multiplexed read-out makes this KID design suitable for next-generation bolometric experiments.