Is there a "faster" photoelectric beam sensor?
The manual for your sensor - briefly - mentions "response time adjustment" via a screwdriver, which would explain the spread. Some applications, such as sensing someone coming through a doorway, require longer response times, so as to not trigger separately for, say, each leg.

In general, the response time of this sensor is going to be limited by the fact that it uses an electromechanical relay, which takes time to physically switch on and off. It's likely the internal electronics were designed with low speed operation in mind as well.

Broadly speaking, if you need high speed measurements, you probably want to look for a sensor that has either a transistor output (open collector, open drain, or logic level), or speaks a communication protocol like I2C or SPI. Sensors like these are likely to be designed around higher data rates and response times. Many of these more specialised sensors may be orientated around measuring distance, rather than just detecting beam breaks, but it's certainly possible to construct a beam break sensor with a fast response time; I'm just not sure if any exist commercially.

In passing, Sparkfun have a Lidar sensor that ought to meet your requirements pretty well.