Photos of Scientifica & Cook Helium-Neon Lasers

These are HeNe lasers made by Scientifica & Cook in the 1970s and 1980s. The first one is complete and consists of a laser head with a two-Brewster tube with a heated filament in a laser head enclosure having painted red side and top panels. A separate unregulated power supply about the size of 2/3rds of a loaf of bread is attaches via two LEMO-style fat cables - one for the high voltage and the other for the filament power and HV return. The second one is only the power supply so far which is similar in size but ha swapped out some high value internal ballast resistor for a two-transistor regulator. It is for a more modern tube with a cold cathode so there is only a single HV cable.

[Only about 3 people per decade visit the Laser Equipment Gallery ;-), the existing format was archaic, and I am lazy. So going forward, we will use the Windows App "Web Album Generator" for most of the collections. Higher resolution versions of the photo are usually available by copying the title under the navigation links (NOT the file name) and appending a ".jpg" to it. Even higher resolution versions may be available to a good cause. Ask.]

Scientifica & Cook HeNe Lasers
Web Album: 48 Photos

Description of the Web Album photos for Scientifica & Cook HeNe laser head and power supply #1:

• System1_Overall1: This shows the dramatic ;-) laser head and power supply connected by the high voltage and filament / return cables, along with the line cord.

• System1_Back1: The back panels showing the connectors and strange black interlock plug and AC line input. The key-lock switch requires a strange round key, availability unknown.

• System1_Front1: The laser head has a black output bezel with beam shutter; the power supply has a boring blank aluminum panel.

• Head1_Top_Overall1: Right-side view showing the laser safety label.

• Head1_Top_Overall2: Left-side view showing the "Scientifica & Cook Gas Laser" label.

• Head1_Back1,2: Back end of laser head showing high voltage connector (left) and return / filament connector (right). These are similar to LEMO™ connectors. The blank aluminum plate can be removed to access the waste beam.

• Head1_Front1,2: Front end of laser head showing the black bezel and shutter knob. There is nothing contained in the bezel and it's not clear if it has any real purpose.

• Head1_Interior1-3: These show the resonator and two-Brewster tube with the covers removed. The large ballast resistor (33k ohms) and fat red HV wire go to the anode at the left; The two fat blue wires are terminated in female socket pins that attach to the filament. There are 2 separate filaments, so should one burn out, the other can be swapped in. There are five IR-suppression magnets glued directly to the tube bore.

• Head1_HR_End1: This is the HR-end of the resonator with the cover plate flipped down but still attached by the HV and filament / return wires.

• Head1_HR_Mirror_Mount1: The mirror is secured inside the mirror mount using a lock ring. The 3 screws are for alignment.

• Head1_Back_Brewster1: The Brewster window is protected by a thin plastic cover secured with an O-ring.

• Head1_Back_Third1: Close-up of the back third of the resonator.

• Head1_Middle_Third1: Close-up of the middle third of the resonator.

• Head1_Front_Third1: Close-up of the front third of the resonator.

• Head1_Tube_SN1: Tube serial number label stuck to tube.

• Head1_Filaments1: Closeup of the 2 filaments. These appear to be pristine. Too bad about the tube. ;-(

• Head1_Front_Brewster1: The Brewster window is protected by a thin plastic cover secured with an O-ring.

• Head1_OC_Mirror_Mount1: This is similar to the one in the back for the HR.

• Head1_OC_End1: This is the output-end of the laser.

• Head1_Aperture_Warning1: There is no indication of the maximum possible power from this laser. But based on the dimensions of the tube and rating of the power supply, it could be 5 mW or more.

• Head1_Laser_Label1: Ealing SCIENTIFICA GAS LASER label on the left side of the laser near the back..

• Head1_Safety_Label1: DANGER label on the right side of the laser near the back. The maximum power stamped on the label is 6 mW and the laser had a Class IIIB designation.

• Head1_Nameplate1: This is on the bottom at the back. The manufacturing date is 17-May-1977 and the head serial number is 556-5. That could translate to the 556 laser build in May (5), though I rather doubt these things were ever that popular. ;-)

• PS1_with_Cover1,2: This is the power supply that went with laser head #1. The physical construction is basically similar to that of the head but shorter. And note the convenient carrying handle. ;-)

• PS1_Back1,2: This shows the HV connector with a single large female socket, the return / filament connector with its 2 female sockets, the strange black interlock plug (assumed to be just a jumper), the Power indicator lamp, the also strange 115 V input socket, fuse, and circular key-lock switch.

• PS1_Side1,2: Views of the interior of power supply #1 showing the massive multi-tapped transformer at the left, bridge rectifier and ballast resistors next to it, followed by the 6-stage starting multiplier in parallel with 3 HV diodes to isolate it from the main output.

• PS1_Top_and_Bottom_PCBs1: The PCB on the bottom has 10 filter capacitors along with equalizing resistors for the main HV output.

• PS1_Transformer_Taps1: The transformer can be jumpered to select 1, 1.4, 1.8, or 2.5 kV nominally at 115 VAC input but that can then be fine-tuned by changing to one of the 10V taps on the input.

• PS1_Nameplate1: This has SCIENTIFICA & COOK ELECTRONICS LTD and the same SN: 556-5.

• PS1_Powering_Modern_HeNe_Laser_Tube1: This is a modern Melles Griot 05-LHR-082 HeNe laser tube. It is multi-spatial mode (MM) rated at 14 mW. The supply happily runs it tapped as shown over a voltage range of at least 110-125 VAC resulting a tube current of approximately 5.0-6.5 mA. At 6.5 mA it would produce more than 14 mW being brand new.

Description of the Web Album photos for Scientifica & Cook HeNe laser power supply #2. There is no telling where the laser head is now, probably a land-fill:

• PS2_with_Cover1-3: This is the power supply that went with laser head #2 (missing in action). This shows the HV connector (smaller than the one on PS #1) which like a modern laser has its own return. Then there is the same strange black interlock plug (assumed to be just a jumper), the Power indicator lamp, the also strange 115 V input socket, fuse, and straight key-lock switch with two (2) keys.

• PS2_Side1-3 and PS3_Top_PCB1: Views of the interior of power supply #2 showing the massive multi-tapped transformer at the left (with protective plastic sheet in the first photo), two-transistor regulator with adjustment trim-pot (range from 6 mA to below 5 mA), a 4-stage voltage multiplier in parallel with HV 3 diodes to isolate it from the main output.

• PS2_Top_and_Bottom_PCBs1: The PCB on the bottom has the bridge rectifier and 10 filter capacitors along with equalizing resistors for the main HV output.

• PS2_Transformer_Taps1: The transformer can be jumpered to select 900?, 1.4, 2.0, or 2.5 kV nominally at 115 VAC input but that can then be fine-tuned by changing to one of the low voltage taps on the input. With the taps selected as shown, this will regulate at 6.0 mA over an input voltage range of at least 110-125 VAC

• PS2_Nameplate1: This has SCIENTIFICA & COOK ELECTRONICS LTD and SN: 749.