This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility:


peer-reviewed publication

trusted source


New type of bolometer detector for far-infrared telescopes

New type of bolometer detector for far-infrared telescopes
(a) SEM micrograph of a spiral antenna coupled MgB2 HEB from the same batch as HEB-A. The inset is a 3D model of the MgB2 submicrometer-bridge and part of the contact pads and the spiral antenna. The colors indicate different materials. (b) Optical micrograph of a device chip, containing four HEBs, from the same batch as HEB-B. A layer of 500 nm thick Si3N4 is sputtered to cover the surface of the chips except for the bonding pads to isolate MgB2 bridges from water and air. The inset in (b) is an artistic impression of HEB-B, which shows exactly the same layout as the design. (c) The resistances of HEB-A and HEB-B as a function of temperature, where the critical temperatures are 33.9 and 38.4 K, respectively. Credit: Journal of Applied Physics (2023). DOI: 10.1063/5.0128791

To study how stars and planets are born we have to look at star cradles hidden in cool clouds of dust. Far-infrared telescopes are able to pierce through those clouds. Conventionally, niobium nitride bolometers are used as the detectors, despite their low operating temperature of 4 Kelvin (-269° Celsius).

Now Yuner Gan (SRON/RUG), together with a team of scientists at SRON, TU Delft, Chalmers University and RUG, has developed a new type of bolometer, made of magnesium diboride, with an operating temperature of 20 Kelvin or above. This can significantly reduce the cost, complexity, weight and volume of the space instruments.

Conventional, superconducting niobium nitride (NbN) hot electron bolometers (HEBs) are so far the most sensitive heterodyne detectors for high-resolution spectroscopy at far-infrared frequencies. Heterodyne detectors take advantage of a local oscillator to convert a terahertz line into a gigahertz line.

This allows them to measure not only the intensity in great detail but also the frequency. Heterodyne detectors have been successfully applied in balloon and space telescopes and are candidates to serve in future missions. Ground telescopes cannot see far-infrared radiation as it is blocked by the Earth's atmosphere.

One drawback of such is its bandwidth, that covers a limited spectral line in one measurement. Another restriction comes from the low operating temperature. Cooling down to 4 Kelvin, either by using a vessel with or a mechanical pulse tube, is undesirable for a space observatory considering the constraints on mass, volume, , and cost.

Yuner Gan and her colleagues have now developed a far-infrared HEB detector based on a new superconducting material—magnesium diboride (MgB2)—which has a relatively high critical temperature of 39 Kelvin. This allows them to get a higher , at 20 Kelvin or more. They have also demonstrated that the novel HEBs have promising sensitivities and a much increased frequency bandwidth.

The publication in the Journal of Applied Physics was selected for the Special Collection Recognizing Women in Applied Physics.

More information: Y. Gan et al, Heterodyne performance and characteristics of terahertz MgB2 hot electron bolometers, Journal of Applied Physics (2023). DOI: 10.1063/5.0128791

Journal information: Journal of Applied Physics

Citation: New type of bolometer detector for far-infrared telescopes (2023, February 17) retrieved 6 June 2023 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Explore further

Bolometers operate at higher temperatures using new superconducting material


Feedback to editors