Thermal crosstalk of X-ray transition-edge sensor micro-calorimeters under frequency domain multiplexing readout

Abstract

We have measured and characterized the thermal crosstalk in two different arrays of transition-edge sensor (TES) X-ray micro-calorimeters with frequency-domain multiplexing (FDM) readout. The TES arrays are fabricated at SRON and are a 8$\times$8 and a 32$\times$32 "kilo-pixel" uniform array. The amount of crosstalk is evaluated as the ratio between the averaged crosstalk signal and the X-ray pulse amplitudes. The crosstalk ratios (CR) for our detectors are compliant with the requirements for future X-ray space missions, such as Athena X-IFU (CR$<10^{-3}$ for first-neighbour pixels): we measured a nearest-neighbour thermal crosstalk ratio at a level of $10^{-4}$, with a highest crosstalk ratio of $4\times 10^{-4}$ for the kilo-pixel array (worst case, center of array) and $1\times 10^{-4}$ for the 8$\times$8 array, with a margin of improvement achievable by optimizing the Cu metallization and the width of the Si supporting structures (muntins) in the backside of the TES array chip. Based on the measured crosstalk ratios, we have estimated the impact on the spectral resolution by means of noise equivalent power (NEP) considerations and a Monte Carlo simulation, finding an average degradation in quadrature of less than 40~meV, compliant with the < 0.2~eV requirement for Athena X-IFU.

References in corpus (6)

• On the use of C-stat in testing models for X-ray spectra
• High Aspect Ratio Transition Edge Sensors for X-ray Spectrometry
• Frequency Shift Algorithm: Application to a Frequency-Domain Multiplexing Readout of X-ray Transition-Edge Sensor Microcalorimeters
• TiAu TES 32$\times$32 pixel array: uniformity, thermal crosstalk and performance at different X-ray energies
• Frequency Shift Algorithm: Design of a Baseband Phase Locked Loop for Frequency-Domain Multiplexing Readout of X-ray Transition-Edge Sensor Microcalorimeters
• Demonstration of MHz frequency domain multiplexing readout of 37 transition edge sensors for high-resolution x-ray imaging spectrometers

Cited by in corpus (3)

• Developments on frequency domain multiplexing readout for large arrays of transition-edge sensor X-ray micro-calorimeters
• Frequency domain multiplexing readout for large arrays of transition-edge sensors
• Signatures of Thermal and Electrical Crosstalk in a Microwave Multiplexed Hard X-ray Transition Edge Sensor Array