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Gamma radiation calculations and gamma blocker design for the high-energy beam transport region of the European Spallation Source


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Fig. 1

The ESS linac schema.
The ESS linac schema.

Fig. 2

Schema of the A2T section of the HEBT area.
Schema of the A2T section of the HEBT area.

Fig. 3

Implemented gamma radiation spectrum from the external target wheel surface – results of simulations in the FLUKA software.
Implemented gamma radiation spectrum from the external target wheel surface – results of simulations in the FLUKA software.

Fig. 4

(a) Schematic view of the target area. Isotropic gamma source was implemented on the external surface of the target wheel (red line). (b) Dose rates obtained after the implementation of the gamma source. The origin of the z-axis starts at the proton source of the linac.
(a) Schematic view of the target area. Isotropic gamma source was implemented on the external surface of the target wheel (red line). (b) Dose rates obtained after the implementation of the gamma source. The origin of the z-axis starts at the proton source of the linac.

Fig. 5

Residual dose rates after five years of continuous irradiation, and no cooling time. The origin of the z-axis starts at the proton source of the linac.
Residual dose rates after five years of continuous irradiation, and no cooling time. The origin of the z-axis starts at the proton source of the linac.

Fig. 6

Gamma radiation dose rate vs. distance from the beam pipe. Projection on X-axis (transverse to the beam axis) at z = 579.5 m, for different cooldown times.
Gamma radiation dose rate vs. distance from the beam pipe. Projection on X-axis (transverse to the beam axis) at z = 579.5 m, for different cooldown times.

Fig. 7

Dose rate after five years of exposure and no cooling time, for different GB thicknesses.
Dose rate after five years of exposure and no cooling time, for different GB thicknesses.

Fig. 8

Residual dose rate vs. distance from the beam pipe. Projection on X-axis at z = 579.5 m after five years of exposure and no cooling time, for different GB thicknesses.
Residual dose rate vs. distance from the beam pipe. Projection on X-axis at z = 579.5 m after five years of exposure and no cooling time, for different GB thicknesses.

Fig. 9

Residual dose rate vs. distance from the beam pipe. Projection in X-axis at z = 565 m, after five years of exposure and no cooling time for different GB thicknesses.
Residual dose rate vs. distance from the beam pipe. Projection in X-axis at z = 565 m, after five years of exposure and no cooling time for different GB thicknesses.

Fig. 10

Residual dose rate inside the beam pipe as a function of GB thickness, after five years of exposure, for various cooling times.
Residual dose rate inside the beam pipe as a function of GB thickness, after five years of exposure, for various cooling times.

Proton beam parameters used in the simulation

Beam properties
Energy (GeV) 2.00
Power (MW) 5.00
Pulse current (mA) 62.50
Average current (mA) 2.50

Dose rates inside the beam pipe, after five years of exposure and various cooling times, for different GB thicknesses

GB thickness (mm) Dose rate after five years of exposure (μSv/h)

No cooling 1 hour cooling 4 hours cooling 1 month cooling
0 3800 ± 152 2060 ± 103 1700 ± 68 230 ± 9.2
50 850 ± 32 460 ± 14.8 370 ± 11 58 ± 2.8
100 180 ± 7.2 92 ± 3.4 72 ± 2.8 9 ± 0.36
150 40 ± 1.6 21 ± 0.84 18 ± 0.72 2.2 ± 0.09
200 14 ± 0.5 6 ± 0.24 5 ± 0.2 0.8 ± 0.03
400 1.150 ± 0.046 0.850 ± 0.034 0.54 ± 0.02 0.200 ± 0.008
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Inglés
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Temas de la revista:
Chemistry, Nuclear Chemistry, Physics, Astronomy and Astrophysics, other