Projectile Detector - Am i using bad op-amps?

Hi guys,

I am designing a projectile detector using an IR LED and an IR photodiode. I have whipped up a circuit that works for low speed projectiles, however it doesnt work quite the same for higher speed projectiles.

Here is my circuit:


PARTS:
*uA741 Op-Amps
*1/4 watt resistors
*200k 3/4 turn potentiometers

THE DESIGN:
On the left side, I have circled the virtual ground circuit. I did this to raise the ground potential of the photodiode well above the ground potential of the second comparator op-amp (since the uA741 does not operate well within about 1.9v of its power or ground rails). The virtual ground is then connected with a reverse biased photo diode to the input of my comparator, which is then wired with the shown feedback loop.

THE PROBLEM:
When moving something quickly through the sensor, I get about a 40mV rise in voltage for the time that the object is in the sensor. When I move something more slowly through the sensor, I get a full 4.4v rise in voltage. I need to find a way to get a full 4.4v rise even for a fast moving projectile.

I am curious if my op-amps are just slow acting, and dont have enough time to rise to full potential for the quick projectile. Should I look at higher quality op-amps? Any suggestions? Is there some other problem Im not aware of?
I also wondered, if I chose a higher potential difference between supply rails, like 9V instead of 5V, would that help get the gain I am looking for?

Thanks for your help, guys!
John

From the 741 spec sheet, its slew rate is slow, compared to many other op amps. Example, the 5534 is a popular high-quality type.

I'm not sure how to advise on whether your setup would benefit from an op amp that works from a single supply, or from a bipolar supply.