TANGRA – A facility for fundamental and applied research

Supervisor: Dr. I. N. Ruskov

Joint Institute of Nuclear Research

Frank Laboratory of Nuclear Physics

Dubna, Russia

Student: David Knežević

Faculty of Science

University of Novi Sad, Serbia

2015 Student Practice in JINR Fields

of Research (3rd stage)

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Project title: Non-destructive analysis of element and isotope composition

by neutron spectroscopy methods

TANGRA (TAgged Neutrons & Gamma RAys)

Signal from α detector

starts the clock Signal from γ-detector

stops the clock

Using the measured time between

signals from α- and γ- detectors, it

is possible to measure the

distance from the n-source to the

point from which the g-ray was

emmited.

Each pixel of

the α-detector

„tags“ one

neutron beam

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

ING-27 Neutron Generator

Maximal Intensity ~5·107s-1

Neutron energy 14.1 MeV

Neutron radiation

mode

Steady-state

Power supply 200 5 V

Maximum power

consumption

40 W

Dimensions 130x279x227 mm

Weight 8 kg

Operation time ~800 hours

Detector of α-

particles

9-pixel or 64-

pixel position

sensitive silicon

detector

Neutron generator 64-pixel α-detector

Produced by:

N.L. Dukhov All-Russian

Automation Research

Institute

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Developed and designed by

JINR

1) Neutron flux is known with high precision: each neutron is “tagged“ by α-detector signal.

2) The space- and time- locations of the interaction of the neutron with a target can be determined (X,Y-coordinates are given by the pixels of the α-detector; Z,t-coordinates are defined by the time-of-flight).

3) Determining the elemental composition of the object (rather than density contrast as conventional X- and γ-ray scanners do) using the characteristic g-rays of elements and isotopes that the object consists of.

4) When using α-γ coincidences the background is significantly reduced.

5) High penetration power of the fast neutrons in air: ~ 1 m

6) Practically no residual radio-activity from the investigated object

Advantages of the “tagged” neutron method (TNM)

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Aims of the project - applications

1. Basic research – Using tagged neutron beams for experimental investigations in the field of fundamental nuclear physics

2. Applied research – Development of the tagged neutron method for identification of a wider range of elements and substances

3. Methodical research – Design and construction of gamma and neutron detectors, development of algorithms for the analysis of experimental data

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Experimental setup

General experimental setup Current experimental setup

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Basic components of the setup are: Neutron Generator,

Shielding Colimators and different Neutron and Gamma

Detectors in different configurations depending on the

experiment

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Angular correlation of gamma-rays in the inelastic scattering of 14 MeV neutrons on carbon

Important for commisioning of the TANGRA setup, and also the angular anisotropy of the emmited gamma-rays has to be taken into account for usage of tagged neutron method for elemental analysis.

8 hours of irradiation with

10x10x5 cm graphite as a target

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Practical work – Calibration of a single NaI(Tl) detector

NaI(Tl)

detector Calibration

source

Different positions

relative to the

detector axis

Different

distances

We used calibration sources with different energies of characteristic

gamma-rays, chosen in such a way to maximize the energy range of the

measurements.

Practical work- Calibration of the whole „Romashka“ setup

Different

positions

Different

heights

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Different position were chosen in order to be able to calculate the

efficiency for the volumic sources as precisely as possible. For the whole

setup calibration, we used five positions, one in the center, and four in the

corners, with seven different heights for each position.

Corner positions

Results

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Collecting and proccesing of the experimental data in order to calculate the apsolute efficiency for volumetric sources is currently taking place at the TANGRA experimental facilty.

Future plans for the projects include:

1. Conduction of measurements of characteristic gamma-spectra for various elements. Creation of data base for element identification.

2. Conduction of experiments on measurements of angular correlations of gamma-ray emission in the reactions of neutron inelastic scattering on light nuclei.

3. Conduction of experiments on measurement of cross-sections in the (n,2n), (n,n`) reactions.

4. Studies of the Martian soil model.

5. Development of the technique for studies of the elemental composition of soils and minerals.

Conclusion

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA

Acknowledgments

I would like to thank the following people for their guidance, lectures and suggestions:

Dr. Ivan N. Ruskov

Dr. Yuri N. Kopatch

Dr. Sergey B. Borzakov

Mr. Dimitar N. Grozdanov

Thank you for your attention!

TANGRA - A FACILITY FOR FUNDAMENTAL AND APPLIED RESEARCH 2015 STUDENT PRACTICE IN JINR FIELDS OF RESEARCH (3RD STAGE)

DAVID KNEŽEVIĆ, FACULTY OF SCENCE, UNIVERSITY OF NOVI SAD, SERBIA