Fragmentation of 1.2 A GeV ${}^7$Be nuclei in nuclear photographic emulsion

The charge topology of peripheral fragmentation of 1.2 A GeV ${}^7$Be nuclei in a nuclear emulsion is presented. The dissociation of ${}^7$Be nuclei via the channels ${}^7$Be${\to }^4$He + ${}^3$He, ${}^7$Be$\to$2${}^3$He + n and ${}^7$Be${\to }^4$He + 2${}^1$H is considered in detail. It is found that in the channel ${}^7$Be${\to }^4$He + 2${}^1$H, events related to the channel ${}^7$Be${\to }^6$Be + n with the cascade decay ${}^6$Be${\to }^4$He + 2p account for about 27 %.