1. A PPLICATION OF SSNTD METHOD FOR MEASUREMENTS OF THE FISSION RATE AND THE NUMBER OF FISSION OF NATURAL URANIUM INSIDE INVESTIGATED ASSEMBLY. E XPERIMENTS WITH THE QUINTA TARGET ASSEMBLY (D UBNA, R USSIA, VBLHEP JINR). R ESULTS OF 46 SESSION (D ECEMBER 2012) Reports: Krystsina Husak, junior researcher of the Laboratory for Experimental Nuclear Research and Expert Analysis of Radioactive Materials of the Joint Institute for Power and Nuclear Research — Sosny

2. C O - AUTHORS : I.Zhuk, О.Bukhal, А.Safronava, А.Patapenka : Joint Institute for Power and Nuclear Research — Sosny Minsk, Republic of Belarus; М.Artyushenko, V.Sotnikov, V.Voronko : National Scientific Center Kharkov Institute of Physics and Technology Kharkov Republic of Ukraine; S. Tyutyunnikov, W. Furman, M. Kadykov : Joint Institute for Nuclear Research Dubna, Russian Federation; A. Chinenov, V Chilap: CPTP “Atomenergomash” Moscow, Russian Federation. The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 2

3. E XPERIMENTS OBJECTIVES WERE : Research experimental studies of:  natural uranium fission rate spatial distribution in QUINTA subcritical assembly;  natural uranium fission number spatial distribution in QUINTA subcritical assembly; Compare total fission number of natural U with results of earlier experiments. 3 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013

4. E XPERIMENTAL ASSEMBLY “QUINTA” The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 4

5. S ENSORS : 5 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 track detectors coupled with nat U foils lavsan strip lavsan (and mica) disk

6. S ENSORS POSITIONS The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 6 Plates number: 0 beambeam 12345

7. 7 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 R ADIAL DISTRIBUTION OF FISSION RATE. E=2 G E V. P LATA 1 (Z= 13.1 CM ).

8. 8 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 Radial distribution SSNTD - lavsan strips E = 2 GeV Distribution of fission rate Axial distribution Fission rate spatial distribution per one cm 3 and one deuteron

9. 9 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 Radial distribution SSNTD - lavsan strips E = 4 GeV Distribution of fission rate Axial distribution Fission rate spatial distribution per one cm 3 and one deuteron Outside position/ lead, 90 cm

10. 10 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 Radial distribution SSNTD - lavsan strips E = 8 GeV Distribution of fission rate Axial distribution Fission rate spatial distribution per one cm 3 and one deuteron Outside position/ lead, 90 cm

11. 11 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 N UMBER FISSION OF NAT U E=2 G E V I T OT =(3.0±0.3)10 13 End face view Side view

12. 12 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 N UMBER FISSION OF NAT U E=4 G E V I T OT =(3.1±0.3)10 13 End face view Side view

13. 13 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 N UMBER FISSION OF NAT U E=8 G E V I T OT =(8.6±0.9)10 12 End face view Side view

14. T OTAL NUMBER FISSION. I N COMPARISON WITH EARLIER RUNS. 14 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013

15. F ISSION RATE OUTSIDE QUINTA. E=2 G E V 15 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 Between sections 2&3 Between sections 3&4 Between sections 4&5 Between sections 1&2 2.44E-14 4.00E-14 3.86E-14 2.44E-14

16. 16 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 F ISSION RATE OUTSIDE QUINTA. E=4 G E V before section 1 4.46E-14 6.20E-14 5.75E-14 after section 5 2.67E-13 3.15E-14 3.91E-14 6.41E-14

17. 17 F ISSION RATE OUTSIDE QUINTA. E=8 G E V 2.16E-13 5.56E-14 6.94E-14 before section 1 after section 5 1.59E-14 2.46E-14 2.48E-14 4.11E-14 5.12E-14 3.51E-14 30 cm

18. C ONCLUSIONS : 1. Uranium fission rate decreases fast in radial distribution. The reasons are: - -QUINTA is deep subcritical assembly; - - Neutrons generated in interaction between incident deuterons and assembly material loose the energy rapidly due to collisions with uranium nuclei (Even one collision is enough the energy be less than fission threshold (1.4 МэВ)) 2. Total fission number of nat U, calculated per a deuteron and per 1 GeV energy of the deuteron, was compared with results of RunMarch-2011, RunDecember -2011, RunMarch -2012 and RunDecember -2012. It does not depend on the primal energy of the deuteron beam. 3. Results of fission rates nat U measurements at the assembly outside will be used for neutron leakage calculation. 18 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013

19. Thanks for attention! The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 19

20. 20 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013

21. Multification factor = number of fission*200 MeV (fission energy) / energy brought by incident beam+1 mf for QUINTA ≈ 3 We have to stick to the plan. And for sudden ideas we use foils which were left. 21 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013

22. Empty area (0<R<4 см и 0<Z<11.5 см )is corresponding to missing uranium rods in cental part of first section. Empty area is corresponding to missing fissile material (clearance between rods and sections). [Each section is composed of uranium rods arranged in the form of hexagonal (triangular) lattice with pitch size of 3.6 cm (aluminium covering – 0.12 cm)] 22 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013

23. I RREGULARITY OF FISSION MATERIAL IN QUINTA Calculation procedure: - Neutron field is symmetrical with respect to principal axis. - Accounting of geometry fissile material spatial arrangement. The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 Monte-Carlo calculation 23 Density of the fission material radial distribution at the assembly QUINTA

24. 24 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 H EAT PRODUCTION E=2 G E V I T OT =(3.0±0.3)10 13 End face view Side view

25. 25 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 H EAT PRODUCTION E=4 G E V I T OT =(3.1±0.3)10 13 End face view Side view

26. 26 The XII-th International School-Seminar "The Actual Problems of Microworld Physics" Gomel, Belarus, July 22 - August 2, 2013 H EAT PRODUCTION E=8 G E V I T OT =(8.6±0.9)10 12 End face view Side view