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Megagrant on Cosmology and European Competition

Name
Leonid
Surname
Kuzmin
Scientific organization
Chalmers University of Technology
Academic degree
Dr.Sci.
Position
Professor
Scientific discipline
Physics & Astronomy
Topic
Megagrant on Cosmology and European Competition
Abstract
For investigation of the Cosmic Microwave Background we developed the Cold-Electron Bolometers (CEB) insensitive to Cosmic Rays.
We are invited to develop detectors for the OLIMPO and LSPE experiments devoted to Syunyaev-Zel’dovich effect.
We are developing multichroic systems based on concept of Resonance CEB invented by Swedish-Russian collaboration for the European COrE space mission. CEB is the only European concept daring to compete with dominating of American concepts.
However, these opportunities to go to the international level do not find proper support of MON.

Keywords
No
Summary

The Cosmic Microwave Background is a powerful probe for the primordial universe and the high energy physics; through the SZ effect it can provide information about the physics of galaxy clusters. The recent joined analysis of BICEP2 experiment and Planck satellite rejected a B-modes detection by   BICEP2, demonstrating the stringent necessity of multifrequency CMB experiments to correct the observations from the dust contributions. The Planck mission produced accurate maps of the sky with performances close to be limited by Cosmic Rays (CRs). This demonstrated the mandatory development of bolometers less affected by the interaction with CRs.

We propose the development of the Cold-Electron Bolometers (CEBs) based on direct electron cooling of the absorber by SIN tunnel junctions.

First tests have provided high level of the immunity of the CEBs chips.  Further tests, with a larger statistics, would strongly confirm these results. CEBs represent a promising alternative to commonly used TES detectors which suffer for CRs sensitivity and other issues (saturation problems, sensitivity to magnetic fields...).

We plan to assess the level of immunity of CEBs towards CRs; optimized CEBs arrays will be developed for studying the interactions with radioactive sources, providing a stringent result about their level of immunity.

In the second part we will develop detectors for the OLIMPO experiment, devoted to Syunyaev-Zel’dovich spectro-photometric observations of galaxy clusters.

In the third part we will develop detectors for the LSPE experiment devoted to study of the primordial universe and the properties of the interstellar dust.

In the field of multifrequency systems we are developing multichroic systems based on two concepts: Resonance Cold-Electron Bolometer (RCEB) and Seashell Slot Antenna. Both concepts were invented by Swedish-Russian collaboration and are developed by ESA (European Space Agency) consortium.

 

The Cosmic Microwave Background (CMB) is the radiation emitted when the universe was about 380000 years old. Its polarized component, B-modes, is a powerful probe for understanding the primordial universe and the high energy physics. Moreover, the CMB interaction with intracluster gas of galaxy clusters (the so called SZ effect) can provide information about the physics of galaxy clusters itself. Recent Planck and BICEP2 experiments only improved upper limits on B-modes. Moreover, the Planck mission was close to be limited by interactions between its detectors and Cosmic Rays (CRs). These demonstrated the necessity of developing multi-frequency experiments to correct B-modes observations from astrophysical contaminant signals with detectors immune to CRs.

We propose the development of the Cold-Electron Bolometers (CEBs), based on direct electron cooling of the absorber by Superconductor-Insulator-Normal tunnel junctions. The smaller volume of absorber makes CEBs intrinsically insensitive to CRs with respect to commonly used bolometers. In this aim, we will fabricate CEBs arrays optimized to strongly assess their level of immunity towards CRs. We propose to develop CEBs for the Italian balloon borne experiments OLIMPO and LSPE, devoted to multifrequency observations of the SZ effect and B-modes, respectively.

CEB is considered as the third concept for a new European COrE (Cosmic Origias aExplorer) space mission after TES and KID American concept. CEB developed by Swedish –Russian collaboration is the only European concept osmelivshayasya to compeate with dominating of American concepts. It looks that we have a unique chance to participate and really contribute to international development of Cosmology.  However, our authorities do not support this participation. This opportunity to go to the international level declared in goals of Megagrants really does not find any support of authorities. Besides that, a very low level of support money is delayed by half a year or more. It creates very difficult situation with support of scientists, especially young scientists. We can accept that MON has problems with money as in whole in Russia but delay with payment is fully responsibility of the MON.