Troitsk nu-mass

Unique Scientific Setup, INR RAS

Troitsk nu-mass overview

Institute for Nuclear Research Russian Academy of Sciences
Head: academician RAS, Tkachev Igor I.
Moscow, Troitsk, Fizicheskaya str, 27

Goal of the research

The device is designed for precise measurement of the beta spectrum from decays of tritium to search for sterile neutrinos in the mass range up to 5-6 keV, possibly up to 7 keV, in the absence of additional systematic effects. From the point of view of explanation dark matter in the form of the existence of warm weakly interacting particles (WIMP), interesting is precisely this range of masses of sterile neutrinos - in the region several kiloelectronvolts. Actually the nature of dark matter, its detection are among the most important areas of research in modern physics and cosmology.

13.7 Mlrd 13.7 Mlrd
One of the theories for evolution of the Universe

The project offers an extension of the research program at the Troitsk Nu-Mass facility in the INR RAS in the direction of searching for an exotic particle - sterile neutrinos.

The two main components of the Unit are a gas source and an electromagnetic spectrometer - are unique. The gas source of hydrogen isotopes helps to avoid extremely undesirable effects of distortion of the electron spectrum from implanted or frozen sources. Electrostatic spectrometer of electrons with magnetic adiabatic collimation has currently the world's best energy resolution of about 0.3 electron volts.

The installation includes a cryogenic helium liquefaction system up to 50 liters of liquid helium per hour and cost in modern prices of about 2 million euros.

The plant is equipped with a large fleet of various cryogenic and vacuum systems, experimental stands, recording electronics and computer systems.

Primary advandages of the setup

Installation Troitsk nu-masses at the moment has no analogues, both in Russia and in the world. On its basis, the most exact limitations on the upper boundary of the neutrino mass were obtained. These restrictions are of a fundamental nature and have been included in all modern bases data on the properties of elementary particles. Annually publication with these data is cited 50-60 times. The uniqueness of the installation is determined by two main components: a gas-free gas source of tritium and an electrostatic spectrometer with a magnetic adiabatic collimation. All components of the installation are unique developments Soviet and Russian scientists. Tritium source allows to work with gaseous tritium, while maintaining the conditions of high vacuum in other parts of the installation. Electrostatic spectrometer 10 meters long and about 40 cubic meters in volume has the world's best energy resolution of about 0.3 electron volts for electrons with an energy of 18 keV.

The cryogenic equipment includes a cryogenic helium liquefaction system from LINDE (Germany) for about 2 million euros. The system provides liquid helium not only needs of the experiment, but also scientific organizations in the city of Troitsk.

All elements of the installation - vacuum and cryogenic systems - are equipped with modern computer control equipment for controlling and controlling the vacuum, temperatures and gas composition of the source.

When measuring, modern electronics are used to record and collect information. In addition, the plant includes a number of vacuum stands, which are used to test individual vacuum cells, to develop and test              new types of electron detectors.

Mounting of spectrometer inner electrode:
Сборка спектрометра


The installation includes the following scientific equipment:
A flawless gas source of hydrogen isotopes, a magnetic electrostatic spectrometer, a cryogenic complex with a helium liquefier, vacuum test benches, two experimental halls. In addition, a precision electron gun with an electron energy of up to 35 keV is installed in the back of the gas source, which is capable of "firing" simultaneously the source and the spectrometer.

In addition to the main equipment, the experiment has two vacuum test benches equipped with the necessary electronics and computer technology.

A gas-free gas source of tritium with a closed circulation of working gas; internal superconducting solenoids 5 meters long during installation:


Integral electrostatic spectrometer with magneto-optical adiabatic collimation, MAC-E filter:

1 - spectrometer supports, 2 - input and output cups, 3 - warm axial windings, 4 - main high-voltage electrode, 5 - electrodes under zero potential, 6 - detector system with liquid nitrogen cooling, 7 - set of superconducting magnets.

Cryogenic complex with helium liquefier LINDE and compressor station:

Linde компрессор

An electron gun with an energy of up to 35 keV and a resolution of 0.3 eV, located in the far part of the gas source:


One of the rooms is equipped for vacuum test equipment testing:


Vacuum chamber for test measurements during installation:


In addition, in order to maintain all the systems in operation and to provide the corresponding work stations in accordance with the Labor Code, the installation includes a system of cold and hot water supply, as well as heating of the experimental halls during the cold period.

Primary research

Search for new phenomena outside the Standard Model of elementary particle physics, search for sterile neutrinos in a cosmologically interesting mass region, development of experimental techniques and software for direct measurement experiments neutrino mass.

The project is aimed at direct laboratory searches for sterile neutrinos. The importance of this kind of search experiments in addition to the constraints arising from different theoretical models is undeniable. The specific task is to significantly improve existing restrictions on the mixing angle of sterile and active neutrinos in the mass range from tens of electron volts and up to 15-17 keV. This range of mass values ​​is not available in oscillatory experiments planned in a number of world scientific centers.

An essential advantage of the installation is the presence of a gas source of hydrogen isotopes. This type of source avoids the extremely undesirable effects of distortion of the electron spectrum from implanted or frozen sources. For solutions we plan to perform a precise measurement of the spectrum of the beta decay of tritium in the whole kinematically accessible energy region, in contrast to the earlier measurements near the boundary point. The laboratory has extensive experience in this installation. In 2013, significant modernization of individual plant elements and the entire power supply system was completed.

The installation started calibration and testing of a new generation of silicon detectors with a structure of charge carrier drift. Detectors are multi-pixel and have very small capacity, at the level of dozens of femtofarads, which allows to drastically reduce noise level. The thin entrance window allows one to drop to an energy of 1-2 keV for the incident electrons. Detectors are developed at the Max Planck Institute in Munich, Germany. A joint agreement has been concluded for joint work. The installation of the Trout of the nu-masses has unique sources of electrons, including electrons from the decay of tritium, which was the determining factor for these joint works.

In parallel with the main project for the search for sterile neutrinos, a compact solid-state source is being searched for a new generation of experiments. In particular, it is promising to develop a solid, safe source of tritium based on graphene. Hydrogen sources on graphene, in general terms, are considered as an option for the safe storage of hydrogen as a new generation fuel.

The installation has received the unsurpassed best limitation on the mass of electron neutrinos:



List of typical services provided

In addition to the main scientific activity related to the precision measurements of the electron spectrum in the decay of tritium, it is possible to perform other works and services at the facility:

  • Investigation and precision measurement of the emission spectra of electrons from gaseous and solid substances in the energy range from 5 to 30 keV.
  • Study of electron scattering by means of a precision electron gun on gaseous samples.
  • Testing of elementary particle detectors in vacuum chambers using different types of sources, including tritium. It is possible to provide high vacuum and cryogenic temperatures.

When performing work for the benefit of outside organizations, the calculation is carried out in the hours of operation of all or part of the installation. At the same time, the cost of services includes the payment of employed personnel, the cost of the necessary materials (for example, liquid nitrogen and gaseous helium, if the work is related to the use of cryo equipment) and preliminary technical work, electricity, overhead, etc.

It should be noted that the installation is available for obtaining bakavrskaya and magistor degrees in the field of experimental and applied nuclear physics under the guidance of qualified specialists.

Regulations for access to the CNU

For the work in the external customer's interlaces, an application must be submitted, which indicates the essence of the planned work or the required experimental developments, the approximate terms of implementation, information about the customer, as well as other information needed for planning the use of equipment. The status of consideration of the application can be checked on this site. After consideration of the application and in the event of its adoption, a civil law contract should be concluded on the performance of work or the provision of services.

The procedure for calculating the cost of non-standard services

The calculation will be made depending on the type and conditions of the provision of services.

Request form

In order to request facility services, submit the following form:

Plans and development

In accordance with the preliminary plans and according to incoming applications in 2018, it is planned to conduct three measurement sessions. The beginning of the first session on April 9, 2018, the end on April 28.
The main work will be devoted to the development of a measurement technique with a multi-pixel silicon drift detector and a set of statistics on the search for sterile neutrinos.

Personnel of the installation

The team of the group working on the plant is 12 highly qualified specialists. Of these, 1 doctor of science, 4 candidates of sciences, 3 engineers in cryogenic engineering, several research workers, 2 mechanics. The device can work up to 2000 hours per year (in case of appropriate financing).

Educational capacity of the installation

The installation provides unique educational opportunities for engineers and physicists, since students and graduate students can not only solve the specific problems they are working on, but also study many aspects of physics and engineering, such as vacuum technology, cryogenics, electronics and much more. At the moment two students of MIPT and one graduate student of INR are involved in the research.


INR RAS: prospekt 60-letiya Oktyabrya 7a, Moscow 117312

Troitsk subdivissuion: ul. Fizicheskaya 27, Moscow, Troitsk 108840

Tel: +7(495)850-42-01,

Head of the project, academician RAS Igor Tkachev, e-mail:

Contact person, prof. dr. Vladislav Pantuev, e-mail:

2010 photo with the founder and former leader of the experiment academician Vladimir Lobashev:

Members ofTroitsk nu-mass II experiment at 2010