Article about Audience Scanning

Discussion in 'Laser Safety' started by Pangolin, Jan 17, 2003.

  1. Pangolin

    Pangolin Staff Member

    Hi all,

    Welcome to our forum on Laser Safety. I am hoping that there will be some lively discussions here.

    Let me start things out on the right foot by saying that there has been some very good research in the field of Audience Scanning recently, particularly by John O'Hagan of the National Radiological Protection Board (NRPB) in the United Kingdom. John has actually produced his doctoral thesis on the topic of A Risk Assessment Methodology for the Use of Lasers in the Entertainment Industry. In particular, his thesis covers safe Audience Scanning techniques. It is an excellent document of over 200 pages. John has made this available on our web page at:

    For those who don't want to quite delve into a 200 page document, you can find a pretty good write-up on producing safe shows using audience scanning techniques at the page:

    This is an article written by me back in 1997. I think it is a particularly good article -- not only because I wrote it, but because it covers things at a pretty understandable level, and yet goes into enough detail to be valuable. This article was also reviewed by Greg Makhov -- ILDA Safety Committee Chairman, and John O'Hagan of the NRPB. This article has withstood the test of time and of peer review.

    Enjoy and feel free to ask questions!!

    Best regards,

    William Benner
    Pangolin Laser Systems

    [ May 30, 2003, 08:26 PM: Message edited by: Pangolin ]
  2. paul

    paul Member

    we've been using John O'hagan from the NRPB on installations in the uk as weve been having inconsistency with council health an saftey on crowd scanning, most of our installs in the uk are 500mw 532nm diodes and from what John O'hagan
    has said is that even when using a difraction grating with out a zero order is that you are still over the mp level. John Tira of the NRPB will not let us crowd scan using the above as it is according to his (NO) meter 130 times over the limit. so this document is going to be very intresting to read, after dealing with them previously.
  3. Pangolin

    Pangolin Staff Member

    Hi Paul,

    Well John O'Hagan certainly knows what he is talking about and I regularly consulted with him during the wriging of that article and even now. If John says there is a problem, then there is. He is not one who just says or does things just to be mean...

    If you are really using a diffraction grating, then it could be that single beams coming from this grating are over the average MPE.

    John is a member of this message forum. Perhaps he will comment when he gets a chance.

    William Benner
    Pangolin Laser Systems