Clustering features of the $^7$Be nucleus in relativistic fragmentation
  Charge topology of fragmentation of 1.2 A GeV $^7$Be nuclei in nuclear track emulsion is presented.The dissociation channels $^4$He + $^3$He, 2$^3$He+ n, $^4$He + 2$^1$H are considered in detail. It is established that the events $^6$Be + n amount about to 27 % in the channel $^4$He + 2$^1$H. 
N. K. Kornegrutsa, D. A. Artemenkov, P. I. Zarubin, R. R. Kattabekov,   K. Z. Mamatkulov
nucl-ex