The intensity and the shape of 1 GeV protons beam from the JINR Dubna Nuclotron (November 2003)

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1 The intensity and the shape of 1 GeV protons beam from the JINR Dubna Nuclotron (November 2003) A. Krása, F. Křížek, A. Kugler, M. Majerle, and V. Wagner Nuclear Physics Institute of the Academy of Sciences of the Czech Republic, Řež near Prague, 25068, Czech Republic The experiment was carried out at the superconducting, strong focusing synchrotron named Nuclotron with proton energy 1 GeV on the Energy plus transmutation installation using a Pb/U assembly. The irradiation began at 13:44:41 and finished at 19:59:43 on 30 th November The course of the irradiation is in Fig.1. The irradiation continued for t irr = s and the total number of beam protons was I(p) = as determined by the current integrator (which suffered from a significant systematic error). Therefore, the beam geometry and total beam flux were measured by the neutron activation analysis method using activation foils of 27 Al, 197 Au, and nat Cu (69.17% 63 Cu, 30.83% 65 Cu). In the process of irradiation, the stable isotopes were transmuted by (p,x nyp)-reactions into radioactive ones. intensity [10 10 protons/bunch] time [seconds] Figure 1: The course of irradiation with 1 GeV protons.

2 2 Beam intensity The total beam intensity was determined by activation of beam monitors composed of 8 8 cm 2 Cu foils with a thickness of 25 µm placed closely in front of the target. The yields (i.e., number of activated nuclei per one gram of activated material and per one incident proton) of several (p,x)-reactions were measured and the following isotopes were identified: 24 Na, 59 Fe, 52 Fe, 58 Co, 57 Co, 56 Co, 55 Co, 54 Mn, 52 Mn, 51 Cr, 48 Cr, 48 Sc, 47 Sc, 46 Sc, 44m Sc, 57 Ni, 48 V, 43 K, 42 K. The values of integral proton flux calculated from yields of each isotope are shown in Table I and Fig.2. The weighted average value of the integral proton flux determined by the activation was (3.26 ± 0.08) The value χ 2 = 1.3. The error of integral proton flux includes statistical errors and inaccuracies of determination of the corresponding cross-sections of (p,x)-reactions, which were acquired by interpolation using EXFOR/CSISRS data base values (mostly [2], [3]), see also Fig.2. proton flux [10 13 ] Na24 Co58 Mn54 Cr51 Sc44m Sc47 flux of 1 GeV protons K42 Co57 Fe52 K43 Mn52 Co56 Sc46 Co55 V48 Sc48 Fe59 Ni57 Cr number of the isotope in the Table 1 Figure 2: Values of integral proton flux determined according to the yields of identified isotopes. The central thick line is weighted average, thinner lines represent error of weighted average.

3 3 Table I: Values of integral proton flux calculated from yields of identified isotopes, cross-sections of corresponding (p,x)-reactions isotope half-life [d] σ [mb] σ [mb] σ / σ [%] I p [10 13 ] I p [10 13 ] 1 24 Na Co Mn Cr m Sc Sc K Co Fe K Mn Co Sc Co V Sc Fe Ni Cr Beam position The beam geometry was studied with the use of high-energy proton reactions on nat Cu. A group of five Cu foils (size 2 2 cm 2 with approximately 50 µm thickness) were placed closely in front of the target and compared the yields in different foils, see TableII, Fig.3 or fluxes through foils, see Fig.4. We used two simple assumptions: the central foil is fully covered,

4 4 Table II: Ratios of yields in central foil to other foils (weighted averages over all observed isotopes). ratio error centre/left centre/down centre/right centre/up ratio central/foil left down right up foil K42 Sc44m Sc47 Mn52 K43 V48 Ni57 Cr48 Co58 Mn54 Cr51 Co57 Fe52 Co56 Sc46 Co55 Fe59 Figure 3: Ratios of yields in central foil to other foils for observed isotopes. the proton distribution is homogenous. From these values, we determined the proton flux in front of the target had ellipse shape with major axis 4 cm (in vertical direction), secondary axis 3 cm (in horizontal direction). The center of the ellipse was shifted 0.5 cm upwards, 0.2 cm to the right, see Fig.5. Conclusions The integral proton flux was determined to be (3.26 ± 0.08) The proton flux in front of the target had ellipse shape with major axis 4 cm and secondary

5 5 flux 1.2E E E E E E E+00 centre left down right up foils Co58 Mn54 Cr51 Sc44m Sc47 K42 Co57 Fe52 K43 Mn52 Co56 Sc46 Co55 V48 Sc48 Fe59 Ni57 Cr48 Figure 4: Fluxes through set of five foils, determined from all observed isotopes. Figure 5: Scheme of shape and position of the beam. axis 3 cm. The center of the ellipse was shifted 0.5 cm upwards, 0.2 cm to the right. [1] Firestone R. B. Table of Isotopes, 8th Edition [2] Aleksandrov Yu. V., et al. (P,X) Reactions Cross Sections in Aluminium at Medium Energy Protons and Production Cross Section For Radioactive Nuclides In Copper Target Bombarded

6 6 by 660 MeV Protons // Jaszuk C. M. and Kaminski W. A., Nuclear phenomenology and neural networks, <<Conference on Nuclear Spectroscopy and Nuclear Structure>>, Moscow, [3] Michel R., et al. Nuclide Production by Proton-Induced Reactions On Elements (6 Z 29) in the Energy Range from 800 to 2600 MeV // Nuclear Instruments and Methods in Physics Research B V P

Cross-section Measurements of Relativistic Deuteron Reactions on Copper by Activation Method

Cross-section Measurements of Relativistic Deuteron Reactions on Copper by Activation Method Nuclear Physics Institute, Academy of Sciences of the Czech Republic Department of Nuclear Reactors, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague Cross-section