Tenerife Microwave Spectrometer: 4K Cold Load


Credits: Instituto de Astrofisica de Canarias (IAC)

The Tenerife Microwave Spectrometer (TMS) is an experiment led by the Instituto de Astrofisica de Canarias (IAC) aimed at the absolute measure of the Cosmic Microwave Background spectral distortions between 10 GHz and 20 GHz, in 40 sub-bands 250 MHz wide each. This measure will open an unexplored window to the early Universe, probing its thermal story, the inflation Era paradigm, the nature of the Dark Matter. Besides of verifying the absolute spectral deviation from a pure Black-Body Law, TMS aims to characterize the absolute synchrotron monopole emission from our Galaxy. The TMS will also support the Quijote experiment, provide an absolute calibration, and be a prototype for similar future experiments, ground and space-based. TMS will operate from the Teide Observatory (Izaña-Tenerife, Spain) operating at 2390 above the sea level.

The TMS 4K Cold Load (TMS 4KCL) is a fundamental subsystem of TMS: it is the calibrator providing TMS with the microwave reference signal. The spectrometer has a pseudocorrelation architecture based on two identical and specular sensitive to linear polarization receivers, each provided with a feedhorn, one looking the sky, the other facing the TMS 4KCL. The two receivers and the TMS 4KCL are actively cooled, in the TMS cryostat, down to a temperature close to the brightness temperature of the sky (about 6K), including the CMB and the atmospheric emission. The TMS 4KCL shall have the spectral emission of a quasi-perfect black body, in the TMS operational frequency range, at physical temperature between 4K and 10K: it shall be able to identify the spectral distortions within a few micro Kelvin of accuracy.

The TMS-4KCL Project is based on a scientific agreement between INAF – OAS (Osservatorio di Astrofisica e Scienza dello Spazio di Bologna) e IAC (Instituto de Astrofísica de Canarias) signed in 2018. INAF-OAS is responsible of the design, manufacturing and verification. The agreement expects the completion of the TMS-4KCL manufacturing within 2020, of the thermal, mechanical and radiometric verification by middle 2021, the integration in TMS and validation within 2022. The scientific commissioning will follow.

OAS involvement:

  • Project & System Management
  • Electromagnetic design
  • Thermal Design
  • Manufacturing
  • Verification & Validation
  • Dissemination


Reference Papers:


Useful links