Projects/Copper

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Oxford Lasers Cu10 10Watt Copper Vapour Laser

Reading Hackspace have a pair of Oxford Lasers CU10 copper vapour lasers under refurbushment.

SAFETY

Additional hazards specific to these lasers.

  • Laser Beam. The laser emits light strongly in both the green(510.6 nm) and the yellow(578.2nm) parts of the spectrum. Normal protective eyewear for green DPSS or Argon lasers is not suitable.
  • High voltages. The voltages present (10kV +) in the laser control unit and the laser head are lethal. There are interlocks on the removable covers and these must not be disabled.

When working on any part of the laser the power cord must be removed from the mains supply. Exposed 240V supply is present in all parts of the control unit and on the printed circuit boards. When working on the High voltage side of the control unit or the head thehigh voltage circuit breaker must be tripped out, and all the capacitors discharged with the earthed wand.

  • High temperatures. The head operates at high temperature and may remain very hot for hours after use. All laser fans in head and control unit must be unobstructed
  • High pressure gas. The neon gas used by the laser is at high pressure.
  • Vacuum. Parts of the control unit and head may be at low vacuum making implosion hazard if broken.

Documentation CU10 Specific

  • Edwards E2M1.5 Vacuum Pump

File:Files Pumps Rotary Vane Pumps Edwards Edwards E2M1.5 Rotary Vane Pump Manual.pdf

  • Thyratron

The thyratron is a EEV (E2V) CX1535 Hydrogen Thyratron capable of 25kV at 1000A peak (25 MegaWatts!). They have limited lifetime, so please keep a lookout on the surplus market.

File:Thyratron info.pdf

There is a full datasheet included here, but I can't extract just the CX1535 part. [1]

  • Thyratron Oil

The manual specifies Shell Diala B G oil (4.7litres) for the Thyratron tank. Shell Dialla B is now replaced with Shell Diala S2 ZU-I, though this is not having a G suffix (gas absorbing) We should check with manufaturer the best currently available oil.

Oxford Lasers CU10 Manual

File:Copperlasers.zip

Applications

Micromachining, Dye pumping and high speed imaging.

Thou shalt not pump narrow-band dyes in thy hackspace lest the men with guns appear.

Current Status

These Copper Vapour lasers were sold to Danny Briggs in 2014. He got one working again and posted this video: [2] It looks like they are now homeless again and coming back to rLab in the near future

Pics and video

  • Gas Related
Neon bottle inside Laser
Neon bottle inside Laser
Where the regulator needs to connect. The cylinder outlet is just behind "Park on the lable"
Where the regulator needs to connect. The cylinder outlet is just behind "Park on the lable"
The internal pipes and the int/ext gas switch all appear to be 1/4" Swagelok type.
The internal pipes and the int/ext gas switch all appear to be 1/4" Swagelok type.
External connection is a 1/4" BSP
External connection is a 1/4" BSP



  • Laser Head
The laser head is seperate from the power and control module and they connect via a large umbilical cable carrying electrics and gasses.
The laser head is seperate from the power and control module and they connect via a large umbilical cable carrying electrics and gasses.


At the rear end of the laser head is the rear mirror which is totally reflecting. The Umbilical enters the laser head here. The "laser on" light and the rear interlock can also be seen.
At the rear end of the laser head is the rear mirror which is totally reflecting. The Umbilical enters the laser head here. The "laser on" light and the rear interlock can also be seen.


The large aluminium block is insulated from the head chassis and is at high potential (10kV) when operating. The first of 3 fans in the laser head can be seen and it blows air onto the heatsink. The heatsink is sealed to the large pyrex tube running the length of the laser. The large blue capacitor (1nf 30kV)is charged from the power unit over the black coaxial cable, and discharges through the laser tube. The heatsink has a silica window for the laser light to exit. The window is removable for cleaninr and reloading the copper in the laser
The large aluminium block is insulated from the head chassis and is at high potential (10kV) when operating. The first of 3 fans in the laser head can be seen and it blows air onto the heatsink. The heatsink is sealed to the large pyrex tube running the length of the laser. The large blue capacitor (1nf 30kV)is charged from the power unit over the black coaxial cable, and discharges through the laser tube. The heatsink has a silica window for the laser light to exit. The window is removable for cleaninr and reloading the copper in the laser
One of three gas connections between the control unit and the laser head can be see passing through an electromagnetic valve. This pipe (yellow) carries neon gas into the laser tube via the high voltage end.
One of three gas connections between the control unit and the laser head can be see passing through an electromagnetic valve. This pipe (yellow) carries neon gas into the laser tube via the high voltage end.
This centre fan blows hot air out from the laser head. The fan shown here was a previous "fix" to the head. The fan is a 240V type not 12V and may be mounted the wrong way round, so must be checked.
This centre fan blows hot air out from the laser head. The fan shown here was a previous "fix" to the head. The fan is a 240V AC type, not 12V DC and may be mounted the wrong way round, so must be checked.
The bottom (white) gas pipe to the control unit connects to the vacuum pump, and the top (black) gas pipe connects to the pressure gauge in the control unit. Both are isolated by electromagnetic valves. They both connect through a 60 micron filter to the ground end heatsink.
The bottom (white) gas pipe to the control unit connects to the vacuum pump, and the top (black) gas pipe connects to the pressure gauge in the control unit. Both are isolated by electromagnetic valves. They both connect through a 60 micron filter to the ground end heatsink.
The ground end heatsink is cooled by another fan.
The ground end heatsink is cooled by another fan.
The front mirror is only slightly reflecting and is the laser output port. I sliding shutter with a heatsink is provided to shut off the beam
The front mirror is only slightly reflecting and is the laser output port. I sliding shutter with a heatsink is provided to shut off the beam


The laser head is extended to include a small optical table area 475mm long and 200mm wide. This area can be used to set up optics to modify the beam before exiting the head. The table surface sits 75mm below the centre of the beam and has 6mm * 1.0mm tapped holes on a 25mm grid.
The laser head is extended to include a small optical table area 475mm long and 200mm wide. This area can be used to set up optics to modify the beam before exiting the head. The table surface sits 75mm below the centre of the beam and has 6mm * 1.0mm tapped holes on a 25mm grid.



This area has a seperate cover and is outside the laser interlocks.
This area has a seperate cover and is outside the laser interlocks.


schematic of the gas flow in the head
Schematic of the gas flow in the head
 electrical schematic of  the head
Electrical schematic of the head
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