Integration interval in tech refers to:
The function f(x) is called the integrand, the points a and b are called the limits (or bounds) of integration, and the integral is said to be over the interval [a, b], called the interval of integration. A function is said to be integrable if its integral over its domain is finite.
So it can be translated to:
مجال عملية التكامل/ المدى عملية التكامل/ فاصل الزمني لعملية التكامل