Project Investigation of Prompt Fission Neutron Emission in Fission (“ЕNGREN”)

 

Investigations of prompt fission neutron emission are of importance in understanding the fission process in general and the sharing of excitation energy among the fission fragments in particular. Experimental activities at JINR on prompt fission neutron (PFN) emission are underway for more than 20 years. Main focus lied on investigations of prompt neutron emission from the reactions ²⁵²Cf (sf) and ²³⁵U(n,f) [2-20,23-26] in the region of the resolved resonances. For the last reaction strong fluctuations of fission fragment mass and the mean total kinetic energy distributions have been observed as a function of incident neutron energy [16, 37]. In addition fluctuations of prompt neutron multiplicities were also observed in [44]. The goal of the present study is to verify the current knowledge of prompt neutron multiplicity fluctuations and to study correlations with fission fragment properties. Recent measurement of PFN multiplicity in resonance neutron induced fission of ²³⁵U(n,f) reaction [27] reveal surprising result, stimulated us to investigate the PFN multiplicity at IREN with new high efficiency  experimental setup.

 

Collaboration

Frank Laboratory of Neutron Physics, JINR, Dubna Moscow region

State University  «Dubna»

UniversityNovi-Sad,Scince Faculty,Physics Division,Novi-Sad,Serbia

Institute of Nuclear Physics and Enginering of Bulgarian Academy of Science (BAS), Sofia, Bulgaria

Project Lider: Zeynalov Sh.S.

Project Deputy: Mytsina L.V.

 

1. Introduction

The possible correlation between the variation of prompt fission neutron (PFN) multiplicity and the fission fragments (FF) total kinetic energy (TKE) variation measurement is the goal of the project. Investigations of PFN properties for more than six decades have reached considerable success due to efforts have been applied to modification of method with low geometric efficiency method (LGE) first suggested by H.R. Bowman et al in Phys. Rev. 126, 2120 (1962). C. Budtz-Jorgensen and H.H. Knitter, suggested twin back-to-back ionization chamber (TBIC) for correlated FF and PFN properties investigation. TBIC along with PFN detector located at ~0.5-0.7 m distance along the axis of the chamber was called method of PFN investigation with low geometric efficiency (LGE ~0.001) [1]. This method provides information on main parameters characterizing correlated FF: TKE, masses, PFN multiplicity, and PFN velocity measured by TOF method. Several experiments improved understanding of fission process with a new data obtained on PFN properties in reactions ²⁵²Cf(sf), ²³⁵U(n_th,f) и ²³⁵U(n_res,f) published in [2-20,23-26]. Interpretation of the experiments was done in the framework of multi modal random neck rupture (MM-RNR) model of low excitation energy fission. The model considers nuclei leaving the compound state by various paths to disintegration. These paths (fission modes) related to Bohr fission channels chosen in stochastic manner by the fissile system. Furman and J. Kliman found link between fission channels and fission modes, providing the way of evaluation the probabilities of fission mode realization using experimental data.

            Recently correction of PFN multiplicity dependence on FF mass and TKE for ²³⁵U(n_th,f)  reaction was reported in [23] (see Fig. 1). Investigations carried out in IBR30 in 1999-2000 pulsed reactor in Dubna [16,17], confirmed existence of TKE variations in neutron resonances first reported by F.-J. Hambsch et al in IRMM [36].  PFN multiplicity measurement with LGE was carried out at GELINA in 2007-2008, using PFN detectors from DEMON collaboration and TBIC loaded by1 mg U235. However, statistical accuracy of data taken in resonances was not enough for reliable PFN multiplicity analysis. Therefore, we developed setup with chamber loaded by 230 mg ²³⁵U target (99.999%) and PFN detector composed of 32 fast neutron detection modules (76 mm diameter, 51 mm thickness) located at distance ~54 cm from the target (LEM =0.012). We expect improve the statistical accuracy of measurement at 9.2 flight path of IREN facility (full neutron beam intensity ~2*10¹¹ sec/4π) at least by order of magnitude.

 

2. Current Status of PFN Investigations

 

First investigation of PFN multiplicity in resonance induced fission reveal multiplicity variations between ²³⁵U(n,f) reaction in resonance energy neutron region [11]. Later in experiments performed in EC-JRC-IRMM [36] variations of TKE in resonance region of neutron energy was observed as demonstrated in Fig. 1. Recently experiments, intended to investigate the

 

Fig. 1 TKE variations in ²³⁵U(n_res,f) reaction measured in GELINA (left graph) and IBR30 (right graph)

 

correlations between FF TKE and PFN multiplicity variations was reported in [27, 33]. Authors used position-sensitive TBIC as FF detector and the array of 12 PFN detection modules. The aim of the experiment was simultaneous measurement of FF TKE and PFN

Fig. 2 Correction of PFN multiplicity dependence on mass&TKE measured in ²³⁵U(n_th,f) in Dubna. Blue line taken from Ref. [40]. Black line is corrected NuBar(A) improves a mass resolution of FF obtained using 2E method.

 

multiplicity variation using LEM. However, simultaneous measurement of FF TKE and PFN has limitation on the target material weigh (should be as thin as possible). For PFN multiplicity variation investigations in JINR at IREN facility we divided experiment by two steps. At the first step PFN multiplicity measured with thick target of 230 mg. At this step we expect most possible PFN production/detection efficiency with available neutron beam intensity. During preparation

 

 

                                               Fig. 3. Experimental setup developed for use in ENGREN project

 

of the project test measurements were carried out. Fig. 4 demonstrates simplified setup used to estimate the time required for PFN variation measurement at IREN facility, having beam intensity ~2*10¹¹ n/sec*4π. Distance between fission chamber and the neutron detector was 17.5 cm in order the PFN detecting efficiency to be close to the PFN detection efficiency of the setup shown in Fig. 3. Fig. 4 demonstrates data acquisition system setup, developed for digitization of PFN and fission detector pulses. Data acquisition software was partially ready, but can be used for test experiment. Only two out of 40 digitization channels were used in test experiment. Resonance neutron time of flight (tof) was measured using time stamps provided by CAEN N6730 waveform digitizer. To obtain correct tof value “T-Zero” pulse from the IREN generated just before neutron burst was used to reset the time stamps counter.

 
Fig. 4 Diagram of the electronic apparatus of data acquisition system

 

             

Fig. 5 Simplified setup

 
Pulse from fission chamber, connected to fission detection initiates time stamp write operation  into waveforms memory buffer. Each fission chamber pulse caused recording of event, consisted of time stamp and two waveforms, recorded from fission chamber and PFN detector.  Data analysis performed offline, creating two types of tof-distributions. In first one each fission event was counted forming tof-distribution. In second one only events where fission events coincided

 

 

Fig. 6 Tof-distributions with demand of coincidence between fission chamber (red curves) and without demand of coincidence (blue curves). Graphs plotted for data collected in two days (~45 hours). Right graph demonstrates thermal neutron energy range of tof-distribution)

 

 

Fig. 7 Fission chamber and PFN detector coincidence waveforms (left graph). Neutron gamma separation graph (central graph). PFN separated from gammas (right graph demonstrates that share of PFN with demand of coincidence is only ~0.13 part of full FF counts, meaning that PFN share is 0.015 of FF counts

 

with PFN detector pulse within 80 ns formed conditional tof-distribution as demonstrated on Fig. 6.  Coincidence between fission event and PFN registration can be caused by prompt gammas.  Hence the coincidence events should be refined from gammas using pulse shape analysis as demonstrated in Fig. 6. The share of PFN is only 0.13 of data collected with coincidence between fission chamber and PFN detector and it is only 0.016 of FF counts. From data analysis of measurement with simplified setup we concluded that for strongest resonances 45 hour measurement of PFN multiplicity provides ~3% of statistical accuracy. 

 

3. Data analysis procedure

 

Data analysis procedure was performed off-line as was described above. Data collected with demand of coincidence with PFN detector first refined from prompt gammas by pulse shape analysis. Then using thermal part of tof-distribution one can obtain average PFN detecting efficiency ξ by normalizing the total number of refined PFN counts to total number of FF. Assuming validity of the formula:

Where we use the following definitions: PFN and FF – are the numbers of PFN and FF respectively, detected in the thermal part of tof-distribution. ξ– is the PFN detection efficiency and 2.41 – is the NuBar value for ²³⁵U(n_th,f) reaction known from the literature. Then for resonances and resonance groups we can use the following formula to calculate the  dependence on neutron energy:

 

                                                .

 

4. Conclusions

The share of PFN is only 0.13 of data collected with coincidence between fission chamber, henсe the share of PFN counts is only 0.016 of FF counts. From analysis of data measured with simplified setup (target of 230 mg) we concluded that for strongest resonances 45 hour measurement of PFN multiplicity would give ~3% of statistical accuracy. For statistical accuracy of ~3% in mass&TKE variation with 1 mg target we will need at least 50 weeks of measurement.  Additionally 50 weeks would be necessary for development apparatus and data acquisition software and preparations at the channel 2 of IREN.  

 

5. Outlook

We are planning to get new data on PFN properties in resonance neutron energy range of ²³⁵U(n,f) reaction as calibration of our method. The next step we will perform measurement of PFN emission in  fission of ²³⁷Np, ²³⁹Pu in the resonances.

 

References

1. Nifenecker, H. Prompt neutron yields of the fission fragments of ²⁵²Cf as a function of the charge of the fragments / H. Nifenecker, M. Ribrag, J. Frehaut, J. Gauriau // Nuclear Physics A - 1969. - Vol. 131, No. 2. - P. 261-266.
2. К.А. Петржак, Г.Н. Флеров, Спонтанное деление урана, Доклады АН СССР - 1940. - Т. 28, № 6. - С. 500-501.
3. Hahn O. and F. Strassmann, Nachweis der Entstehung aktiver Bariumisotope aus Uran und Thorium durch Neutronenberstrahlung, Naturwissenschaften – 1939. -  27. -P. 89-95
4. Meitner and O.R. Frisch, Disintegration of uranium by neutrons: a new type of nuclear reaction, Nature - 1939. - Vol. 143. - P. 239-240.
5. R. Frisch, Physical evidence for the division of heavy nuclei under neutron

        bombardment Nature, 1939. - Vol. 143. - P. 276.

6. R. Bowman, S. G. Thompson, J. C. D. Milton, W. J. Swiatecki, Velocity and angular distributions of prompt neutrons fromspontaneous fission of 252Cf , Physical Review - 1962. - Vol. 126, No. 6. - P. 2120-2136.
7. R. Bowman, S. G. Thompson, J. C. D. Milton, W. J. Swiatecki, Further Studies of the Prompt Neutrons from the Spontaneous Fission of Cf²⁵², Physical Review - 1963. - Vol. 129, No. 5. - P. 2133-2147.
8. Skarsvag, I. Singstad, Angular correlation of fission fragments and prompt gamma rays from spontaneous fission of Cf252, Nuclear Physics - 1965. - Vol. 62, No. 1. - P. 103-112.
9. E. Howe, T.W. Phillips, C.D. Bowman, Phys. Rev. C 13, 195 (1976)
10. Oed, P. Geltenbort, F. Gonnenwein, T. Manning, D. Souque, High resolution axial ionization chamber for fission products Nuclear Instruments and Methods in Physics Research - 1983. - Vol. 205, No. 3. - P. 615 – 617
11. Budtz-Jorgensen and H.-H. Knitter, Simultaneous investigation of fission fragments and neutrons in ²⁵²Cf(sf), Nuclear Phys A – 1988. - Vol. 490, P. 307 – 328.
12. S. Vorobyev, O.A. Sherbakov, Yu.S. Pleva, A.M. Gagarski, G.V.Valski, G.A.Petrov, V.I.Petrova, T.A. Zavarukhina, Measurements of angular and energy distributions of prompt neutrons from thermal neutron-induced fission Nuclear Instruments and Methods in Physics Research A - 2009. - Vol. 598. - P. 795-801.
13. S. Kapoor, R. Ramanna, P.N. Rama Rao, Emission of Prompt Neutrons in the Thermal Neutron Fission of U²³⁵ Physical Review – 1963. –Vol. 131, -P. 283-296.
14. S. Samant, R.P. Anand, R.K. Choudhury M. S. Samant, S. S. Kapoor, and D. M. Nadkarni, Prescission neutron emission in ²³⁵U(n_th,f) through fragment-neutron angular correlation studies Physical Review C -1995. –Vol. 51. –P. 3127-3135.
15. Oberstedt, F.-J. Hambsch, and F. Vives, Fission-mode calculations for ²³⁹U, a revision of the multi-modal random neck-rupture model, Nuclear Physics A – 1998. – Vol. 64. No. 4. – P. 289-305.
16. Zeinalov Sh.S., Florek M., Furman W.I., Kriatchkov V.A., Zamyatnin Yu. S., Neutron energy dependence of ²³⁵U(n,f) mass and TKE distributions around 8.77 eV resonance VII International Seminar on Interaction of Neutrons with Nuclear – Dubna: JINR, -1999. -E3-1999-212. –P. 258-262.
17. Zeinalov Sh.S., Florek M., Furman W.I., Kriachkov V.A., Zamyatnin Yu.S, Neutron Energy Dependence of Fission Fragment Mass & TKE Distributions of ²³⁵U(n,f)- Reaction Below 10 eV, Dynamical Aspects of Nuclear Fission: Proceedings of the 4-th International Conference - Casta-Papiernicka: Slovak Republic, - ed. J. Kliman - World Scientific, Singapore, 2000. -P. 417-423.
18. Zeynalov Sh., Hambsch F-J., Varapai N., Oberstedt S., Serot O., Prompt fission neutron emission in resonance fission of ²³⁹Pu, XII International Seminar on Interaction of Neutrons with Nuclear – Dubna: JINR, -2004. –E3-2004-169. –P. 371-379.
19. A.Sokol, Sh.S.Zeinalov, S. Šaro, M.Hussonnais, H.Brucherseifer, G.V.Bouklanov, M.P.Ivanov, Yu.S.Korotkin, V.I.Smirnov, L.P.Chelnokov, G.M.Ter-Akopian, G.N.Flerov, Preliminary results on the study of ²⁵⁹Md spontaneous fission parameters, JINR Rapid Communications - 1986. – No. 19-86. P. 45-49.
20. A.Sokol, Sh.S.Zeinalov, G.M.Ter-Akopian, Prompt fission neutron multiplicity of ²⁵⁶Fm, Atomnaya energiya – 1989. – Vol. 67, P. 357-358.
21. Bohr, J.A. Wheeler, The mechanism of nuclear fission, Physical Review, 1939. - Vol. 56, No. 5. - P. 426-450.
22. Brosa, S. Grossmann, Nuclear scission, A. Mũller, Physics Report, 1990. - Vol. 197, No. 4. - P. 167-262.
23. Sh. Zeynalov, Sedyshev, V. Shvetsov, O. Sidorova, Prompt fission neutron investigation in ²³⁵U(n_th,f) reaction, EPJ Web of Conferences 146, 04022 (2017) , DOI: 10.1051/epjconf/201714604022
24. Sh. Zeynalov, Sedyshev, V. Shvetsov, O. Sidorova, Position sensitive twin ionization chamber for nuclear fission investigations, Applications of Nuclear Techniques (CRETE17), International Journal of Modern Physics: Conference Series, Vol. 48 (2018) 1860123 DOI: 10.1142/S2010194518601230
25. Sh. Zeynalov, Sedyshev, V. Shvetsov, O. Sidorova, Prompt Fission Neutron Investigation in ²³⁵U(n_th,f) and ²⁵²Cf(sf) Reactions, Wonder-2019, EPJ Web of Conferences 211, 04003 (2019), DOI:10.1051/epjconf /2019/21104003
26. Zeynalov, P. Sedyshev, O. Sidorova, V. Shvetsov, Nuclear Fission Investigation with Twin Ionization Chamber, Applications of Nuclear Techniques (CRETE19), International Journal of Modern Physics: Conference Series, in print
27. Alf Gook, Franz-Josef Hambsch, and Stephan Oberstedt. EPJ Web of Conferences 1 , 05001 (2016)
28. V. Zeynalova, Sh.S. Zeynalov, F.-J. Hambsch, S. Oberstedt, Bulletin of Russian Academy of Science: Physics, 73, 506-514 (2009).
29. Zeynalov, O. Zeynalova, F.-J. Hambsch, S. Oberstedt, A new approach to prompt fission neutron TOF data treatment, Physics Procedia 31 ( 2012) 132 – 140
30. Zeynalova, Sh. Zeynalov , F.-J. Hambsch and S. Oberstedt, “DSP Algorithms for Fission Fragment and Prompt Fission Neutron Spectroscopy in Application of Mathematics in Technical and Natural Sciences-2010, edited by M. D. Todorov and C. I. Christov, AIP Conference Proceedings 1301, American Institute of Physics, Melville, NY, 2010, pp. 430-439
31. Zeynalov, O. Zeynalova, F.-J. Hambsch, P. Sedyshev, V. Shvetsov, Ionization chamber for prompt fission neutron investigation, Physics Procedia 59 (2014) 160 – 166
32. Zeynalov, S., Hambsch, F.-J., Oberstedt, S., 2011. ND-2013, Korean Phys. Soc. 59, 1396
33. Al-Adili, D. Tarrio, F.-J. Hambsch, A. Gook, K. Jansson, A. Solders, V. Rakopoulos, C. Gustavson, M. Lantz, A. Materrs, S. Oberstedt, A.V. Prokofiev, M. Viladi, M. Osterlund, and S. Pomp, EPJ Web of Conferences 122, 01007 (2016)
34. Zeynalov, P. Sedyshev, O. Sidorova, V. Shvetsov, Applications of Nuclear Techniques (CRETE17), International Journal of Modern Physics: Conference Series, Vol. 48 (2018) 1860123.
35. Gook, F.-J. Hambsch, and M. Vidali, Prompt neutron multiplicity in correlation

with fragments from spontaneous fission of ²⁵²Cf.  Phys. Rev. C 90, 064611 (2014)

36. -J. Hambsch, H.-H. Knitter, C. Budtz-Jorgensen, and J.P. Theobald, Fission mode fluctuation in the resonances of ²³⁵U(n,f), Nuclear Physics A -1989. -Vol. 491. –P. 56 – 90.
37. Gook, W. Geerts, F.-J. Hambsch, S. Oberstedt, M. Vidali, Sh. Zeynalov A position sensitive twin ionization chamber for fission fragment and prompt neutron correlation experiments, Nuclear Instruments and Methods in Physics Research A830 (2016) 366
38. Gook, F.-J. Hambsch, S. Oberstedt, Prompt neutron emission and energy balancer in ²³⁵U(n,f), ND-2016, EPJ Web of Conferences 146, 04007 (2017)
39. Laurent, P. Marini, G, Belier, T. Bonnet, A. Chatillon, J. Taieb, D. Etasse, M.Devlin, R. Haight, New prompt fission neutron spectra measurements in the ²³⁸U(n,f) reaction with dedicated setup at LANCE/WNR, ND-2016, EPJ Web of Conferences 146, 04014 (2017).
40. F. Apalin, Yu. N. Gtitsuk, I.E. Kutikov, V.I. Lebedev, and L.A. Mikaelyan, Nucl. Phys. 55, 249 (1964)
41. B. Kaufman, E.P. Steinberg, B.D. Wilkins, J. Unik, A.J. Gorsky and M.J. Fluss, Nucl. Instr. and Meth. 115 (1974) 47.
42. Budtz-Jorgensen, H.-H. Knitter, Ch. Straede, F.-J. Hambsch and R. Vogdt, Nucl. Instruments and Meth. A258 (1987) 209-220
43. C. Vu, A. M. Sukhovoj, L. V. Мitsyna, Sh.Zeinalov, N. Jovancevic, D.Knezevic, M.Krmar, and A.Dragic, Representation of Radiative Strength Functions within a Practical Model of Cascade Gamma Decay, PHYSICS OF ATOMIC NUCLEI Vol. 80 No. 2 (2017)

  

Collaboration

Shakir Zeynalov – PhD in Physics.

Has competence and good experience in realization of national and international projects (IAEA, 1997-1999, EC-JRC-IRMM, 2004-2009). He has experience in the following research areas: Heavy ion reaction, alpha spectroscopy, fission investigation of heavy ion production reactions, spontaneous fission, neutron induced fission, Multiple neutron and gamma emission detectors, design of modern experimental facilities for investigation of nuclear fission, nuclear electronics system design, design of digitization system and digital signal processing, computer programming using modern software and operating systems.

 

Sidorova Olga – PhD in mathematics.

Has good experience in solution of partial derivative equations of mathematical physics, has good experience in using specialized packages of programs (ORIGIN, MathLab) for data analysis in scientific investigations. She is professional in applications of digital signal processing for analysis of pulses from nuclear detectors. In addition she is specialist in Monte Karlo simulation of detector system response to particle registration  

 

Mytsina Ludmila –PhD in Physics.

Has good experience in data analysis of experimental data.

 

Suhovoy Analoly –PhD in Physics.

Has good experience in data analysis of experimental data.

 

Grigorian Roland, Kamyshnikov Denis - students from Dubna  University

 

Yovancheich Nicola – PhD in physyics, from the University Novi-Sad, Serbia

 

Semkova Valentina – PhD in physyics,  from Institute of Nuclear Physics and Nucler Energy of Bulgarian Academy of Science, Bulgaria.

 

Kuznetsov Alexey – Head of FLNP Workshop

 

Lebedev Artem – engineer

 

 

Contacts

Project Lesader Shakir Zeynalov- This email address is being protected from spambots. You need JavaScript enabled to view it.

Project deputy Mytsina Ludmila This email address is being protected from spambots. You need JavaScript enabled to view it.

Adressс: Frank Laboratory of Neutron Physics (FLNPH),  Joint Institute for Nuclear Research (JINR), Joliot-Curie  6, 141980 Dubna, Moscow region, Russian Federation

 

*Testing mode

Responsible for the facility
Inga Zinicovscaia
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
tel. +7 (496) 21 6-56-09

 

Group Staff

 

The principal characteristics of neutron activation analysis facility REGATA 

Distance between irradiation  and measurement positions  (Ch2)  (Ch1-cadmium case)	60 m 70 m
Air pressure	3-7 bar
Transportation capsule types	polyethylene,  teflon,  aluminum, titanic
Internal volume of transportation capsule (Ø 16  mm, H - 22- 35 mm)	3.5 – 5.5 сm3
Maximum irradiation time with 2.0 Mw power for capsules: polyethylene   teflon	0.5 h 3 h
Transportation time for capsule: polyethylene teflon , aluminum	10-20 s 3-8 s
Thermal neutron flux     Ch2	1.5× 1012 n/s сm2
Resonance neutron flux    Ch1	3.6× 1011 n/s сm2
Mass of sample for analysis depends from type of sample	1 mg – several grams
Detection limit depends on elemental composition of the sample and type of sample and can reach, for example, 10-10  for vegetable samples. Around 45 elements can be determined for such type of samples.

 

The principal characteristics of  spectrometers and spectra analysis

- Four HPGe detectors with efficiency 40-55% and resolution 1.8-1.9 keV (Canberra)
- Spectrometric electronics - analog type and digital processors (Canberra)
- Automated system for spectra measurement for three detectors
- Software for spectra analysis - Genie-2000 (Canberra)
- Software package for storage of information and automation of all stages of NAA (FLNP JINR)
- Low background detector with low background shield (Canberra) for measurement of environmental samples

 

Projects: 

Грант РФФИ 18-29-25023 мк «Изучение процессов сорбции и аккумуляции ионов металлов из комплексных растворов на различных типах биологических сорбентов», 2018-2020 гг.

Грант РФФИ 19-015-00145 А «Изучение влияния наночастиц металлов на репродуктивную функцию самок мышей и оценка когнитивных способностей потомства, подвергшегося воздействию наночастиц в период пренатального развития», 2019-2021 гг.

The project "TANGRA" (TAgged Neutrons and Gamma RAys) is devoted to study of neutron-nuclear interactions, using the tagged neutron method (TNM).  The essence of TNM is to register the characteristic nuclear gamma-radiation, resulting from the interaction of neutrons from the binary d(t, 4He)n reaction with the nuclei of the substances under study, in coincidence with the accompanying alpha-particles detected by the position-sensitive alpha detector located inside the neutron generator vacuum chamber.

 

Collaboration: JINR (FLNP, VBLHEP, DLNP, LRB), Dubna, Russia VNIIA (Moscow, Russia) Diamant LLC, Dubna, Russia SINP-MSU (Moscow, Russia) INRNE-BAS (Sofia, Bulgaria) IC-ASM (Chisinau, Moldova) IGGP-ANAS (Baku, Azerbaijan) DP-Banaras Hindu University (Varanasi, India) SEPE, Xi’an Jiaotong University (China) Alexandria University (Egypt) University of Novi Sad (Serbia) Ruđer Bošković Institute (Zagreb, Croatia)

 

I. TANGRA Setups

Multidetector, multipurpose, multifunctional, mobile systems, to study the characteristics of the products from the nuclear reaction induced by 14 MeV tagged neutrons. TANGRA Setups consist of a portable generator of “tagged” neutrons with energies of 14.1 MeV, ING-27, with or without an iron shield-collimator, 2D fast neutron beam profilometer, arrays of neutron-gamma detectors in geometry of daisy-flower (Romashka, Romasha, HPGe), and a computerized system for data acquisition and analysis (DAQ).

 

NaI(Tl) Romashka

 

            

Number of NaI(Tl) detectors: 22
NaI(Tl) crystals: hexagonal prism (78 x 90 x 200 mm)
PMT type: Hamamatsu R1306
Gamma-ray Energy-resolution ~ 7.2% @ 0.662 MeV
Gamma-ray Energy-resolution ~ 3.6% @ 4.437 MeV
Gamma-ray Time-resolution ~ 3.8ns @ 4.437 MeV

 

BGO Romasha

Number of BGO detectors: 18
BGO crystals: cylinder (76 x 65 mm)
PMT type: Hamamatsu R1307
Gamma-ray Energy-resolution ~ 10.4% @ 0.662 MeV
Gamma-ray Energy-resolution ~ 4.0% @ 4.437 MeV
Gamma-ray Time-resolution ~ 4.1ns @ 4.437 MeV

 

HPGe Romasha

 

Number of HPGe detectors: 1
Type: Ortec®GMX 30-83-PL-S, f57.5 x 66.6 mm
Gamma-ray Energy-resolution ~ 3.4% @ 0.662 MeV
Gamma-ray Energy-resolution ~ 0.3% @ 4.437 MeV
Gamma-ray Time-resolution ~ 6.1 ns @ 4.4437MeV

 

II. Science

• Neutron Induced Nuclear Reaction Characteristics:
  Neutron-Nuclear Reactions theory
  Nuclear Astrophysics (Fusion in Tokamak and Stars)
  Neutron-Nuclear Reactions in Advance Reactors
• Elemental and Isotopic Composition of materials
  Nuclear Forensics (Explosives, Drugs, Fissile Materials)
  Art, Archeology, Mining (Diamonds, Coke)
  Nuclear Geophysics and Planetology (Water on Mars)
  Neutron Imaging, Radiography and Tomography
  Neutron-Nuclear Medicine (Cancer treatment)
•  Methodical Research
  Detectors for use in intense neutron fields
  Algorithms for the analysis of experimental data

 

III. Contacts

TANGRA collaboration,                   tangra.collaboration@ mail.ru
Leader: Y.N. Kopatch,                     kopatch@ nf.jinr.ru
Deputy: V.M. Bystrytsky,                 bystvm@ jinr.ru
Coordinator: I.N. Ruskov,                ivan.n.ruskov@ gmail.com
Address: Frank Laboratory of Neutron Physics (FLNF), Joint Institute for Nuclear Research (JINR), Joliot Curie str. 6, 141980 Dubna, Moscow region, Russia

 

*Testing mode

 

Neutron radiography and tomography (NRT)

 

Resposible for the facilty

The neutron radiography and tomography methods are a powerful tool of non-destructive analysis, playing an important part in industrial and scientific research. The fundamental difference in the nature of neutron interaction with matter compared to X-rays provides additional benefits to neutron methods, including sensitivity to light elements, notable difference in contrast between neighboring elements or isotopes, high penetration into metals or heavy elements. All these features make neutron radiography and tomography highly demanded tools with a growing range of applications in industry, geophysics, paleontology, archeology and other various fields, including cultural heritage investigations. A neutron radiography and tomography facility operates at the IBR-2 high-flux pulsed reactor. The main parameters of this facility are listed below. 

Fig. 1. At the top: The layout of the neutron radiography and tomography facility on the 14^th beamline of the IBR-2 high-flux pulsed reactor. The length of the collimator system is 11 m, and the linear dimensions of the neutron beam at the output of the system are 20×20 cm. The goniometer is used for performing the neutron tomographic experiments. A specially constructed detector system based on a high-resolution CCD camera is used for neutron detection. At the bottom: a primary schema of the neutron radiography experiment: a neutron radiographic image of the object is formed using the scintillator screen. Neutron radiography image is recorded by means of the CCD video camera.

 

Several neutron radiography images, as examples, are shown in Figure 2.

Fig. 2. Neutron radiography images of metal casing hard drive, padlock and part of turning lathe.

 

Table 1. Main parameters of the neutron radiography station at the IBR-2 reactor

L/D ratio  Aperture diameter D Distance between input aperture and sample L Beam dimension: Field of view (FOV) Neutron beam flux	200-2000 10-50 mm 10 m 20x20 cm2 5.5(2)x106 n/cm2/s
CCD camera type  Active pixels Pixel size (µm) CCD chip area (mm) Digitization Cooling method	VIDEOSCAN-11002-2001   4008x2672 9x9 12 Bits Peltier element
Scintillator screen specifics	6LiF/ZnS scintillator Gadox scintillator
Spatial resolution	134 µm
Imaging data processing	ImageJ, H-PITRE, VGStudio MAX 2.2 software

 

References

1. Kozlenko D.P., Kichanov S.E., Lukin E.V., Rutkauskas A.V., Bokuchava G.D., Savenko B.N., Pakhnevich A.V., Rozanov A.Yu., Neutron Radiography Facility at IBR-2 High Flux Pulsed Reactor: First Results, Physics Procedia 69, 87 – 91 (2015).
2. Kozlenko D. P., Kichanov S. E., Lukin E. V., Rutkauskas A. V., Belushkin A. V., Bokuchava G. D., Savenko B. N. Neutron radiography and tomography facility at IBR-2 reactor, Phys. Part. Nuclei Lett., 13: 346 (2016).
3. E.V. Lukin, D.P. Kozlenko, S.E. Kichanov, A.V. Rutkauskas, G.D. Bokuchava, B.N. Savenko “First attempts on energy-selective neutron imaging at IBR-2”, Physics Procedia, 69, 271 – 274 (2015).
4. S.E. Kichanov, D.P. Kozlenko, T.I. Ivankina, A.V. Rutkauskas, E.V. Lukin, B.N. Savenko “The Neutron Tomography Studies of the Rocks from the Kola Superdeep Borehole”, Physics Procedia, 69, 537 – 541 (2015).
5. S. Kichanov, I. Saprykina, D. Kozlenko, K. Nazarov, E. Lukin, A.
Rutkauskas, B. Savenko, “Studies of Ancient Russian Cultural Objects Using the Neutron Tomography Method” J. Imaging, 4(2), 25 (2018) 6. S. E. Kichanov, D. P. Kozlenko, E. V. Lukin, A. V. Rutkauskas, E.
A. Krasavin, A. Y. Rozanov, B. N. Savenko “A neutron tomography study of the Seymchan pallasite”, Meteoritics & Planetary Science, 53, 10,
2155-2164 (2018)
7. S.E. Kichanov, D.P. Kozlenko, A.K. Kirillov, E.V. Lukin, B., Abdurahimov, N.M. Belozerova, A.V. Rutkauskas, T.I. Ivankina, B.N. Savenko “A structural insight into the Chelyabinsk meteorite: neutron diffraction, tomography and Raman spectroscopy study”, SN Applied Sciences, 1:1563 (2019).