Where can i find PIR specification?

Hi, I am doing my final year project regarding to PIR sensor which i am going to use PIR sensor to sense the human body temperature. I have do some research on PIR. I found out that is very difficult to get the PIR sensor information. Now, even i don't know there are how many types of PIR sensor in the maket which is easily to get.May somebody guide my where should i go, to search (internet) for the PIR temperature sensor infomation? hank you very much.

I just tried a Google search for 'ir temperature sensors' and it came up with several sources.

Thank you. But the sensor i using is PIR sensor. The sensor that i ca search from google is IR temperature sensor. PIR is just a litter pyroelectrical infrared component. May i know is therer any other source to get this PIR sensor? thank ouy very much.