Energy-dependent fragmentation cross sections of relativistic ${}^{12}\mathrm{C}$

The fragment production excitation functions of ${}^{12}\mathrm{C}$ interacting with carbon nuclei were measured in the energy range of 100–400 MeV/u. To measure cross sections as excitation functions, fragments produced from a thick carbon target bombarded with a monoenergetic ${}^{12}\mathrm{C}$ ion beam were detected by a telescope detector placed behind the target. By this measurement, eight isotopes—${}^{11}\mathrm{B},{}^{10}\mathrm{B},{}^{10}\mathrm{Be},{}^9\mathrm{Be},{}^7\mathrm{Be},{}^8\mathrm{Li},{}^7\mathrm{Li}$, and ${}^6\mathrm{Li}$—were identified, and the energy dependence of their production cross sections in the few 100 MeV/u range was obtained. Based on the measured cross sections, the JAERI quantum molecular dynamics model was updated to incorporate the mechanisms particularly important for peripheral collisions. The improved version of the model coupled with a statistical decay model reproduces the measured data typically within a few 10% of difference.

Figure 1

Schematic diagram of experimental setup (units are mm, not to scale). Detectors 2 and 3 were moved from position $♯1$ to $♯5$.

Figure 2

Block diagram of the signal-processing circuit. CFD: constant fraction discriminator; Disc: discriminator; Coinc: coincidence; GG: gate generator; ADC: analog-to-digital converter; TDC: time-to-digital converter; Int.Reg: interrupt register; Out.Reg: output register.

Figure 3

Two-dimensional distribution of detector 2 output vs TOF.

Figure 4

Two-dimensional distribution of detector 3 output vs TOF obtained at detection position 1 (most forward point).

Figure 5

Angular distribution of fragments produced at 400 MeV/u measured behind target. Closed circles represent measured data, and solid line shows Gaussian fit to data.

Figure 6

${}^{12}\mathrm{C}{{(}^{\mathrm{Nat}}\mathrm{C},X)}^{11}\mathrm{B}$ cross sections. $▵$: Calculation by PHITS-JQMD-2.0; $\times$: Calculation by PHITS-JQMD; blue filled circles: measurement in this experiment; the circles filled with other colors denote literature data.

Figure 7

${}^{12}\mathrm{C}{{(}^{\mathrm{Nat}}\mathrm{C},X)}^{10}\mathrm{B}$ cross sections.

Figure 8

${}^{12}\mathrm{C}{{(}^{\mathrm{Nat}}\mathrm{C},X)}^{10}\mathrm{Be}$ cross sections.

Figure 9

${}^{12}\mathrm{C}{{(}^{\mathrm{Nat}}\mathrm{C},X)}^9\mathrm{Be}$ cross sections.

Figure 10

${}^{12}\mathrm{C}{{(}^{\mathrm{Nat}}\mathrm{C},X)}^7\mathrm{Be}$ cross sections.

Figure 11

${}^{12}\mathrm{C}{{(}^{\mathrm{Nat}}\mathrm{C},X)}^8\mathrm{Li}$ cross sections.

Figure 12

${}^{12}\mathrm{C}{{(}^{\mathrm{Nat}}\mathrm{C},X)}^7\mathrm{Li}$ cross sections.

Figure 13

${}^{12}\mathrm{C}{{(}^{\mathrm{Nat}}\mathrm{C},X)}^6\mathrm{Li}$ cross sections.

Figure 14

Contribution to ${}^7\mathrm{Be}$ production in ${}^{12}\mathrm{C}{(}^{\mathrm{Nat}}\mathrm{C},x)$ reactions from different impact parameter ranges as simulated using JQMD-2.0.

Figure 15

Double-differential neutron production cross sections of 100 MeV/u ${}^{12}\mathrm{C}({}^{\mathrm{Nat}}\mathrm{C}$,x) reactions calculated by JQMD, JQMD-2.0, and literature data [49].

Figure 16

Double-differential neutron production cross sections of 290 MeV/u ${}^{12}\mathrm{C}{(}^{\mathrm{Nat}}\mathrm{C},x)$ reactions calculated using JQMD, JQMD-2.0, and literature data [50].

Figure 17

Double-differential neutron production cross sections of 290 MeV/u ${}^{12}\mathrm{C}{(}^{\mathrm{Nat}}\mathrm{C},x)$ reactions at 20 degrees calculated using JQMD, JQMD-2.0, and literature data [51].

Figure 18

Contribution to neutron production double-differential cross sections in ${}^{12}\mathrm{C}{(}^{\mathrm{Nat}}\mathrm{C},x)$ reactions by 290 MeV/u ${}^{12}\mathrm{C}$ from different impact parameter ranges in simulation using JQMD-2.0.