设\(f\left( x \right)\)是定义在\(R\)上的偶函数，对任意\(x\in R\)，都有\(f\left( x+4 \right)=f\left( x \right)\)，且当\(x\in \left[ -2,0 \right]\)时，\(f\left( x \right)={{\left( \dfrac{1}{3} \right)}^{x}}-6.\)若在区间\(\left( -2,6 \right]\)内关于\(x\)的方程\(f\left( x \right)-{{\log }_{a}}\left( x+2 \right)=0\left( a > 1 \right)\)恰有\(3\)个不同的

实数根，则实数\(a\)的取值范围是(    )