6.
如下图在直三棱柱\(ABC-{{A}_{1}}{{B}_{1}}{{C}_{1}}\)中,\(\angle BAC=\dfrac{{ }\!\!\pi\!\!{ }}{2}\),\(AB=AC=A{{A}_{1}}=1\),已知\(G\)与\(E\)分别为\({{A}_{1}}{{B}_{1}}\)和\(C{{C}_{1}}\)的中点,\(D\)与\(F\)分别为线段\(AC\)和\(AB\)上的动点\((\)不包括端点\()\),若\(GD\bot EF\),则线段\(DF\)长度的取值范围为\((\) \()\).