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Coherent everpulse 11 nd:YAG LASER information needed

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Z28Fistergod

Mon May 11 2009, 12:09AM

Registered Member #2040 Joined: Fri Mar 20 2009, 10:13PM
Location: Fairfax VA
Posts: 180

Ideally I would like a copy of the user manual and/or service manual. What I really need to know is what the pulse forming network looks like, capacitor ratings, series inductors, and the like. I have searched the web extensively and can't find much beyond the basic specs so any information I can get would be greatly appreciated. Thanks.

...

Mon May 11 2009, 12:49AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

If you want a reasonable answer you are going to need to provide a lot more information than the name of the laser. Your best bet at finding a manual would be to contact coherent, but it won't be much good since the manual for big yag lasers usually don't include much information on how to build a new pfn for the laser head (they are 60 pages of relevant safety information, how to wire in the system, if you are lucky there will be decent specifications and alignment procedures).

However there is hope--yag lasers are pretty forgiving in what you feed them, and are all built pretty much the same so if you can provide some basic specs (flash lamp length/diameter, rod dimensions, what kind of cooling, etc) we can probably point you in the right direction.

And you definitely need to post more pictures of the beast! I am pretty sure the everpulse are Nd:glass lasers good for tens of joules output energy!

Z28Fistergod

Mon May 11 2009, 01:36AM

Registered Member #2040 Joined: Fri Mar 20 2009, 10:13PM
Location: Fairfax VA
Posts: 180

LOL
If I had a lot more information I wouldn't be asking this question!
I'll tell you everything I know.

60J peak pulse energy @ 1ms
40J nominal with 4.5% efficiency
14" rod and 2 flashlamp's
water cooling

Which means a capacitor bank energy of 889J at 40J. Efficiency probably drops a bit at peak power so I can make a rough estimate of about 1500J at 60J output energy. That gets me a little closer but I am still in relatively poor shape since I don't know the operating voltage. Maybe we can make a rough estimate based on tube length, being 14" long I would guess more than 1kv and less than 2kv, but this is a complete guess. Once I know the voltage I can assume a current pulse of somewhere around 500us(?) since the laser pulse is 1ms, and maybe reverse engineer the series inductance also.

Anyway there is a whole lot of assuming going on and I would much rather have some solid figures.

I contacted Coherent and they say that they sold their medical division to Lumines and I should contact them. Lumines never manufactured the laser and they have no idea what I'm talking about. I sent another email to Coherent and I'm waiting for a reply. So, like I said any information is appreciated. Thanks.

Steve Conner

Mon May 11 2009, 09:20AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Do the flashlamps have part numbers on them? Whoever manufactured the laser, they probably bought the lamps from someone else, like Perkin-Elmer. So you could get the lamp datasheet, and that might tell you more about what kind of igniter and PFN to use.

Z28Fistergod

Mon May 11 2009, 12:11PM

Registered Member #2040 Joined: Fri Mar 20 2009, 10:13PM
Location: Fairfax VA
Posts: 180

I don't have the head yet so I can't say.

...

Mon May 25 2009, 05:34AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Most flashlamps are made semicustom (which is a large part of why they are so expensive new), and the part numbers are per order and you would need to convince the manufacture (probably Perkins-elmers) to tell you information about them--which is a pretty long shot.

However, perkin-emers has some very complete literature abotu their tubes, which can be found

clck the 'catalog' pdf link on the right side of the screen, I would assume it is a QXF series, which is good for 1.5-5kv and about 1-3KA current. The catalog also explains now to design your PFN network around the tube, so it should at least be a good start.

MinorityCarrier

Tue May 26 2009, 10:38PM

Registered Member #2123 Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312

Our Nd:YAG laserscribe uses OEM Ar flash lamps model L6474. the tube is just under 15cm long, .5 cm diameter. Flash lamp water cooling is by immersion in 18-megohm de-ionized water. That needs to be changed out as the water slowly dissolves metal, it's resistance falls, and begins to shunt some of the flashlamps power dropping overall laser output..

Just my two cents...

likewhat

Wed May 27 2009, 02:07AM

Account deactivated by user request on 6/11/2009.
Registered Member #1071 Joined: Fri Oct 19 2007, 02:13AM
Location:
Posts: 44

I recently built an amplifier for a YAG laser and i will tell you what I used for it.

The laser head part is from a metal cutting laser but I am using it in a MOPA where I am putting a 100ps pulse from a modelocked oscillator into it to get higher power. It has a single flashlamp about 10 inches long. I am using a 400uF capacitor that I charge to 2kV. The way this thing works it you charge the capacitor up against the flashlamp, no switch or inductor involved, although the charging cable is about 8 feet long so that probably slows it down quite a bit. The triggering is done by an ignitor that is capacitively coupled to the charging cable. The ignitor has a small capacitor at 500V that is discharged through an SCR into a transformer. when triggered, it throws the 2kV side of the flashlamp up to about 20kV for about 2 us. the 2kV charge on the capacitor was picked because below this the lamp would not break down, it would just flash while the ignitor pulse was on, but the main capacitor would not flow through it. I dont need much energy from this thing, but 400uF was the capacitor that I had lying around, I would rather use maybe a 100uF.

With the longer lamp you may need to use either a bigger ignitor or more voltage on the capacitor, my supply goes to 10kV i think, but that is getting a bit scary with 400uF capacitor.

Dont know if that helps or not, but that is what i did.

Z28Fistergod

Wed May 27 2009, 02:18AM

Registered Member #2040 Joined: Fri Mar 20 2009, 10:13PM
Location: Fairfax VA
Posts: 180

Well thanks everybody, I have made some progress through E-Bay of all places. There is a guy selling the power supply for the laser and in the listing he shows that there are two storage capacitors, 185uF 3000V Maxwell pulse capacitors. So that helps me out a lot, now if I can figure out the inductance I would be set.

LutzH

Mon Jun 08 2009, 07:50PM

Registered Member #1721 Joined: Sat Sept 27 2008, 08:44PM
Location:
Posts: 136

Hello:

Here is your solution:

Do a Yahoo search under "Fenix Calculator"

Then enter all the lamp parameters, and you will have everything to calculate anything you need :)

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