photo-detector tube construction laboratory considerations dean walters argonne national laboratory

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Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

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Page 1: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

Photo-detector Tube Construction Laboratory Considerations

Dean WaltersArgonne National Laboratory

Page 2: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

2D. Walters

[email protected]

Collaboration Meeting

11 June 2009

Requirements of a Tube Construction Laboratory

Center will need to include:

– Wet chemistry cleaning

– Plasma Etching

– Vacuum Firing

– Test Equipment

– Photocathode deposition and photo-detector assembly system The center should locate all of the operations in a central location to minimize

handling and to control the surface qualities for repeatable results.

– The center needs to control dust and particulate contamination.

– It needs to control temperature and humidity, important in the Midwest.

– It needs services for water, electrical, dry nitrogen, liquid nitrogen, compressed air, process gases, and exhaust gas venting.

– It should be near the materials characterization laboratories. This will be the central point where the parts from external suppliers will be

delivered This is a tube construction center where the anticipated production rate will be

1-2 units a week.

Page 3: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

3D. Walters

[email protected]

Collaboration Meeting

11 June 2009

Initial Steps

Prior to starting the construction of the tube the parts need to be prepared.

Page 4: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

4D. Walters

[email protected]

Collaboration Meeting

11 June 2009

Outline of Processes for the Manufacture of a Photo-detector Tube

Lower Body Construction Cleaning Facility Photocathode Fabrication Photo Detector Assembly System

Page 5: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

5D. Walters

[email protected]

Collaboration Meeting

11 June 2009

Lower Tube Assembly The parts making up the Lower Tube Assembly will be pre-processed

prior to being assembled.

– The anode plate will be glass fritted sealed to the side-wall.

– The NEG strip will be cut and formed to fit within the glass locating pins.

– The MCP’s will be plasma cleaned and then assembled into the Tube Assembly.

MCP’sAnode plate fritted to side-wall

NEG Strip

The top face of the side-wall will be coated with chromium & indium to facilitate the top seal.

Indium on side-wall

Page 6: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

6D. Walters

[email protected]

Collaboration Meeting

11 June 2009

Top Plate

Wet chemistry and plasma cleaning The top plate will need to be prepared for the top seal.

– Using a mask to protect the area of the photocathode, chromium & indium will be deposited onto the glass plate.

– Then heat cleaning can be employed to purify the indium which will aid in the integrity of the joint.

Page 7: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

7D. Walters

[email protected]

Collaboration Meeting

11 June 2009

Photocathode Deposition & Photo-detector Assembly System

Dual chamber manual process system Deposition Chamber

– Ability to degas sources without contaminating other parts.

– Once shutter is open, it will act a shield for the other parts to prevent accidental deposition

– There will be the ability to monitor the deposition through current measurement while the photocathode is being illuminated

Scrubbing and Bonding Chamber– This will house the electron source

to scrub the MCP.– The detachable cylinder will apply

the force necessary to affect a pressure indium seal.

System will be bakeable to 350 C

Page 8: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

8D. Walters

[email protected]

Collaboration Meeting

11 June 2009

Industrial Photo-detector Processing System

Page 9: Photo-detector Tube Construction Laboratory Considerations Dean Walters Argonne National Laboratory

9D. Walters

[email protected]

Collaboration Meeting

11 June 2009

Conclusions

As steps are worked out more of the requirements for the construction of the tube become better known.

– The anode will be silk screen onto the bottom plate.

– The side-wall will be frit sealed onto the bottom plate

– The MCP’s will be coated using ALD and processed in an high temperature that will leave them in a very clean condition.

– An indium joint is being worked on that will be the final tube seal.

– The processes within the final processing station are now becoming better known.• Final vacuum bake of all components• Activation on NEG• Final plasma clean-up of MCP• Deposition of photocathode using in-situ monitoring• Indium seal to complete the tube• Determination of indium seal integrity• Determination of photo-detector operation• Controlled venting of the system