http://ServerName/xrayhistory/(ei15rqrcmc0d1srlkko4bjmo)/xrayhistory.aspx

What is this: (ei15rqrcmc0d1srlkko4bjmo)? (in my page url)

That isn't part of the path to my page but it gets added when I run it.
I am using Windows authentication. Could it be the Windows SID?
It is not always the above characters, it changes each time I log in.
Is there a way to avoid it?

Thanks