A plea for safety, pl edition.

[mixedgas]

Steves two favorite beam dumps.
Both invented by others.

Believe it or not, a stack of single sided steel razor blades enclosed in a small box. The very sharp knife edges diffract the light and stainless steel is actually quite good at adsorbing. Takes massive amounts of power, very well. Just one blade on top of another, and clamped together. Somebody had a now expired patent on this.

Poor mans beam dump #2, a sort of DMills variation.
Only I use a carbon rod from a welding shop for the 45' piece.
You grind the graphite on a grinder, gives it a nice rough surface,
but makes one heck of a mess if your not careful!

Professional ones tend to use a series of blackened disks mounted in a long tube, often with fins or water cooling. There is a hole in the center of each disk, and a solid scatterer at the end: If you space the disks far enough apart, you have baffles. Usually the hole in the disks gets bigger at the back.

Graphite rods get shaped with a grinder, chuck the rod in a drill if you want a cone.

Flat graphite plates come from glassblowing places like WALE Apparatus Co.

Steve
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[mixedgas]

From Skyzan II Software, by Rockwell Laser Safety, inc

Kind Courtesy of , Laser Wizardry, INC.

.25 second standard exposure, typical for airspace safety paperwork.

Some numbers based on Wicked's claimed 445 nM Artic Blue, others are things I have needed in the past, and some are just made up examples.

The KTP532 and Tandom Pair AR/KR ion numbers are from a real show, as are the Laserscope KTP532 numbers.

Do note how things change for my 2003 New Years Eve show , when we change from graphics, to beam effects at 15' max angle from the horizon, this is why pilots are concerned about lasers, even when at altitude.

Just so they don't get reused on a submission document, by someone who is lazy, KTP and Tandem Pair numbers are copyright 2010, All rights reserved.

All numbers are in Feet, because the Aircraft governing body in the US uses FEET!

We know most nations use meters. We know we should round these off as needed.
But its just for a example.

For Mr Bionic-Badger, 223 meters, calculated, is correct for the numbers stated by Wicked for Arctic III device.

NOHD = 2.6 mW per cm ^2
SZED = 5o uWatts per cm^2
CZED = 5.0 uWatts per Cm^2
LFED = 500 nanowatts per cm ^2

Nominal Ocular Hazard DISTANCE = NOHD
Sensitive Zone Exposure Distance = SZED
Critical Flight Zone Exposure Distance, = CZED

BE CAREFUL, Please do not go measure off a distance and look down a beam based on these numbers, each individual laser is different, and thus measurements have to be made,

Steve

----------------------------------
AT 1.5 mm and 1 milliradian:
1 WATT 445 nm
WICKED Arctic III Blue

NOHD = 734 feet
SZED = 3702
CZED = 16,556
----------------------------------------
At 1.5 mm and 1.5 Milliradian
1 WATT 445 nm
Wicked Arctic III Blue

NOHD = 489 Feet
SZED = 2468
CZED = 11,037
------------------------------
At 1.5 mm and 2 milliradians for 405 mW
400 mW

NOHD = 232 Feet
SZED = 1171
CZED = 5235
-------------------------------
At 2 mm and 3 milliradians for 405
400 mW

NOHD = 155 FEET
SZED = 780
CZED = 3490
-----------------------------
1.5 mm and 2 milliradians for 650 nm
250 mW

NOHD = 183 feet
SZED = 926
CZED = 4139
------------------------------

1.5 mm and 1.5 mR 650 nm
250 mW

NOHD = 245 feet
SZED =1234
czed =5519
---------------------------
.65 mm and 1 mR 532
200 mW

.8801

NOHD = 328 feet
SZED = 1656
CZED = 7404
----------------------------------
.65 mn and 1 mR 532
1000 mW
NOHD = 734 feet
SZED = 3702
CZED 16,556
-------------------------------
KTP532 Q switched
40 watts
4 x10-3 Joule per Pulse.
4 x10-7 pulse width
10 Khz rep rate
2 mm dia
5 mR divergence

NOHD = 1761 FEET
SZED = 4683 FEET
czed = 20,942 FEET
LFED = 209,419 FEET

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

Steve's New Years EVE Show, FAA/CDRH approved, 2003
12 Watts 457-676 1 mR
Tandem pair of Ion Lasers, One Argon, One Krypton

Angle of Elevation zero degrees, (graphics mode)
NOHD = 2215 FEET
SZED = 12,827 FEET
CZED = 57,400 Feet


With respect to aircraft, my show, at 15' Up ANGLE FROM THE SCANNERS:
(Beam Effects Mode.)

NOHD = 2215, --- 651 foot altitude
SZED = 12,827, --- 3320 Foot Altitude
CZED = 57,400 ---14,856 Foot Altitude
(obviously why pilots can get very annoyed!)


Visual correction Factor for 445 nm = .0305
Visual correction Factor for 443 nm = .0275
Visual correction Factor for 405 nm = .0008
Visual correction Factor for 650 nm = .107
Visual Correction Factor for 532 nm = .8801

--- msg ends---

[dsli_jon]

..sorry, Steve...

...this little puppy has never let me down for up-to 50+W...



....real-simple to machine-up, even from scrap-stock lyin around... For anything less than 5W, you can leave the 'heat-sink' off... just pop a 'threaded-insert' in the far-end, and screw-to your
favorite-style L-brackky...

...We now return to our regularly-scheduled "Excellent-Point, Steve"...

peace...
j

[mixedgas]

Jon,

With proper credit given, can I use that JPEG on that "OTHER FORUMN?"

They have little clue about the need for such things yet.

Steve

[ElektroFreak]

Believe it or not, a stack of single sided steel razor blades enclosed in a small box. The very sharp knife edges diffract the light and stainless steel is actually quite good at adsorbing. Takes massive amounts of power, very well. Just one blade on top of another, and clamped together. Somebody had a now expired patent on this.

That's golden!! Thanks for sharing that one.

[dsli_jon]

Hey P'fesser...

Jon,

With proper credit given, can I use that JPEG on that "OTHER FORUMN?"

Of course! and certainly, no 'credit' necessary... "...found this on PL" would be best, anyway... (...get more 'converts'... )

peace...
j

[Eidetic]

The stack of razors beam dump is a Thorlabs product.

[polishedball]

Steve and Jon thanks for posting the design ideas.

John

[danielbriggs]

<OFF TOPIC>
These look cheap: http://www.lasersurplusparts.com/sho...?id_product=27

Just ordered one to give it a go. Made from graphite...
I know the guy who machines these
</OFF TOPIC>

[mixedgas]

<OFF TOPIC>
These look cheap: http://www.lasersurplusparts.com/sho...?id_product=27

Just ordered one to give it a go. Made from graphite...
I know the guy who machines these
</OFF TOPIC>

Um, yeah, the graphite needs to be at the back of a tube for high powers, just for visual safety. There is nothing more annoying then working on a lab bench all day with bright laser glare. Well, there are a few things more annoying, like music from Alanis Morrisette singing about her sex life, but not many...

But the price is not bad, considering the mess that machining carbon makes, and the time to go buy a rod.:-)


Steve