open a secondary window/tab in the browser from php

Hi, I have an application that along filling in some forms, it produces a pdf file, as confirmation of all entered data. I want to send this pdf file to a different window/tab of the browser, so it is displayed and can latter be printed. In the mean time, the original window contains a confirmation message, to continue with the work flow. I would like to do this without use of JavaScript.... Any combination of headers ?? Any hints appreciated. JCG