Russian laser show 'blinds' revellers

[UV99LASER]

You can clearly see it is a pulsed yag laser in the video here http://www.youtube.com/watch?v=hXfyDUJjVq4 You can see the pulses in the video between 1:10 and 1:12 minutes.
I have five 20 to 40 watt pulsed yag lasers and that is what they look like when they are scanned.

Only a complete JACKASS would shine a laser on a human for any other reason than surgery.
Audience scanning is stupid no matter who does it or if they have a Variance for it.
Audience scanning sends the wrong message that lasers are safe to point in your eyes.
Jackasses.

[James Lehman]

Again, I'd have to agree.

If someone really wants to put on a laser show that involves scanning _toward_ people, how hard is it to figure out how to stay a few feet away from the tops of heads? If the audience is small enough and in a boxed set of seats, you can wrap all around them with no chance of ever hitting them. DUH!

James.

[Pitts]

Keep an eye on the ILDA website and forum. There is some information starting to come forward on there.

Cheers
Ray

[lasrgreg]

I'd like to make a couple of comments. To the guy who lost the show because of the nervous parents, I truly sympathize. This is a worry for all people engaged in laser displays, pretty much everywhere. Perception problems can kill us far quicker than any regulations.

Second, concerning audience scanning, it can be done safely, and produces effects that are impossible with any other medium. I will be happy to argue this with anybody! However, it must be done carefully, as one is working close to the MPE boundary, and good technique and equipment is essential.

What happened at Aquamarine 4 is probably a last minute stupid decision by someone with little knowledge of what they were working with. Promoter was probably on their back - "WHERE ARE THE LASERS!!!!" "YOU WON'T GET PAID UNLESS YOU TURN ON THE LASERS!!!" I can see this picture pretty clearly.

What is worse about this then all of the same people who probably have hearing damage from the same event? Or the accident today at a Swedish theme park that injured 30? People get hurt at events on a regular basis, whether it is their own stupidity, or they were just in the wrong place at the wrong time, or that somebody screwed up!

Does anyone remember the pyro accident at the WWE Championship at the Citrus Bowl? Line rockets going into the audience because a cable came undone? Is that as scary as a laser injury?

Laser shows actually have a very good track record in safety, in spite of all the idiots, so I think the real problem is not that they are suddenly revealed as "dangerous", but that there is a complacency among users, and discussions of safe practice are considered boring.

People call for operator certification and regulation. I have proposed this on several occasions and maybe we will see some action now. I strongly feel that industry standards are the way to go, rather than government regulation.

Let me pose this question: what is a laser certificate worth? In dollars (or currency of choice)... What will such a certification mean? To your regulators, to your customers? ESTA has a successful ETCP program, and now, several years later, it is starting to carry some weight. Some employers may require it for specific jobs. Would a similar certification for lasers be meaningful? When you are hired by a client, do they even ask about laser safety?

Finally, we are still gathering information about the incidents at Aquamarine 4. We don't know what type of lasers or what power. From the video that was in a previous post (Thank You!) I would say it is hard to tell. The first bit of footage suggests to me maybe Copper Bromide, but could also be a QS Nd:YAG. But I can't rule out even a normal CW DPSS laser. I am not sure if the footage following the camera flash is even the same event.

To the person asking about the 800 mW laser and audience scanning, let me say that the answer is complicated. A single direct 800 mW beam is dangerous for quite some distance, about 430 feet based on a 1.5 mRad beam. Scanning the beam only reduces the hazard slightly, maybe by a factor of 4. The bottom line is that if you don't have the equipment to measure the possible exposure in the audience, or don't understand what a safe exposure would be, don't produce these effects. If you want to learn how to do this, that is a different matter.

Greg Makhov
Lighting Systems Design, Inc.
greg@lsdi.com

[DZ]

Wow, THE Greg Makhov! Great to see you on this forum!

If you want to learn how to do this, that is a different matter.

Hey, speaking of this, have you heard of SELEM? I'm sure several folks would benefit from a lecture on safe audience scanning and we would be greatful to have you as a guest speaker!

[Pitts]

Hi Greg,

Great you came on the forum.

What about sharing a little of that safety training course you have been developing. The one you showed me when I was on my training with you.

I just had this very debate over "time tunnels" and audience scanning with a potential client down here. (got the old, well if you dont the other guy will treatment...well good luck).
At this time I do not yet understand enough of the potential risks and control methods so have decided audience scanning is not an option for me at this time.
There is no actual policing rules for this down here but if we want to avoid them then we need to get our act together.
This Russian matter plus dumb behaviour with high power pointers may see knee jerk reactions from ill informed government agencies, local bodies, Aviation authorities etc.

Hey don't forget I owe you and Phylis a dinner if you make it down here to NZ... and boy did that training help !!! .. (eat your hearts out guys I had two days with Greg @ LSDI with one on one training...)

Stay on the forum the guys would love your input when you have time.

Cheers

Ray
New Zealand

[Dr Laser]

Hi Greg,

Great you came on the forum.

What about sharing a little of that safety training course you have been developing. The one you showed me when I was on my training with you.

I just had this very debate over "time tunnels" and audience scanning with a potential client down here. (got the old, well if you dont the other guy will treatment...well good luck).
At this time I do not yet understand enough of the potential risks and control methods so have decided audience scanning is not an option for me at this time.
There is no actual policing rules for this down here but if we want to avoid them then we need to get our act together.
This Russian matter plus dumb behaviour with high power pointers may see knee jerk reactions from ill informed government agencies, local bodies, Aviation authorities etc.

Hey don't forget I owe you and Phylis a dinner if you make it down here to NZ... and boy did that training help !!! .. (eat your hearts out guys I had two days with Greg @ LSDI with one on one training...)

Stay on the forum the guys would love your input when you have time.

Cheers

Ray
New Zealand

If the time tunnel is done properly it's safe.

[ildadirect]

A time tunnel effect using high-inertia scanning is one of the easiest to do safely.

Use a rotating motor with a mirror, such that if power is cut to the motor, the mirror continues to rotate for a while. A scan-fail circult is used so that if power goes out or motor rotation stops (look for pulses from bars on the back of the mirror), the laser is shuttered. Due to the high inertia, the laser beam keeps moving even if the shutter circuit is relatively slow to act.

Under normal operation, the motor speed is constant. Thus, the circle swept out by the motor can be considered at any given point to be a laser pulse of constant frequency. The pulse of course is the RPM.

Measure a static beam bouncing off the (unmoving) mirror at the closest audience distance, to find the irradiance (power over area). Now you have the key parameters of irradiance and pulse duration. Calculate the MPE for an appropriately pulsed beam.

You may find you need to turn the laser down or (better) increase the divergence, in order to stay at or below the MPE for your particular pulse rate.

That's the general principle, maybe Greg can do a sample calculation. My math skills are such that I would not want to lead anyone astray .

[Pangolin]

Hi all,

We have pretty much confirmed that this show did indeed use a pulsed laser. It appears to be a Q-switched YAG. As noted by Greg in the past, the only documented and confirmed injuries to happen on a mass scale in the past, used a pulsed laser (in that case, a copper bromide laser).

The lesson? NEVER NEVER NEVER USE A PULSED LASER FOR AUDIENCE SCANNING!!

As for the actual calculations for audience scanning exposure, you can find some useful resources here:
http://www.pangolin.com/resguide09a.htm
and here:
http://www.pangolin.com/resguide09b.htm

The last time there was something stupid that happened, and that might have affected the laser industry, Patrick and I worked on a few pages to explain the great safety record of laser companies, and laser threats in general. That was regarding aircraft pilots and laser safety. You can read those pieces here:
http://www.pangolin.com/resguide09c.htmand here:
http://www.pangolin.com/resguide09d.htm

Best regards,

William Benner
President, Pangolin Laser Systems, Inc.

------------------------------------------------------

PS: The links and information provided above are not a shameless plug. Nothing about those links promote any particular company. They are put there for information only. I hope everyone will find the information useful.

Also, one thing to keep in mind. As this story progresses, news outlets will no doubt surf the web for information. We want as much GOOD information out there as possible for the news outlets. That's another reason why I have provided the links above.

[Dr Laser]

I also have a confirmation from very good source that indeed it was pulsed laser. Who the !@#$ in their right mind would do that. Also from the video clips I saw.. show SUCKED ARSE(In artistic term)!. It was basically a Medical surgery on big scale.