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			Track to cluster association
			-------------------------------
ntcl ......... # of tracks-to-cluster association

************** arrays of NTCL ******************8

Asstr(ntcl) ... track # associated
Asscl(ntcl) ... cluster # associated
xext(ntcl) .... Xextrapolation
yext(ntcl) .... Yextrapolation
zext(ntcl) .... Zextrapolation
Assleng(ntcl).. Length from first hit to the cal. surface
AssChi(ntcl) .. Association Chi2