I personally don't have the datasheet on the 8844 but I do have some information I can fill you in on with these tubes, plus I happen to have an 8844 myself
http://troysvintagevideo.0catch.com/tubes.html . Anyways the 8844 is a 2/3" vidicon with magnetic focus and separate mesh and 90mA heater and from CQ-TV magazine issue 149 here are the list of 8844 equivalents with the same characteristics: E1170, M7075, P8037, TV8800, XQ1310, XQ1311, 20PE13, 20PE13A, 8823 and 9831. These 2/3" vidicon tubes were very widely used in many semi professional cameras along the lines of the Sony AVC-3250 studio camera and many other brands that used 2/3" vidicon tubes. The quality from these tubes are absolutely awesome when in good shape and well set up, you get a nice crisp, sharp B&W picture! The easiest way I know of to test the tubes is to get a working camera that uses these type of tubes and replace the tube with the tube you're testing and see if it outputs an image, I know the Sony AVC-3250 uses this tube type so if you have one of those that works you're in business.