Ideas for finding UV from streamers in ProtoDUNE Ideas, drawings, - - PowerPoint PPT Presentation

Ideas for finding UV from streamers in ProtoDUNE

Ideas, drawings, photos, etc. by Francesco Pietropaolo, Jim Stewart, Heng-Ye Liao, Bo Yu... and possibly others (slides put together by Glenn H-S.)

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What are the streamer-vulnerable locations in SP?

We need to know where it is happening to know how to scale “HV downtime”. (~10% in PD-SP) At a cathode corner: FD-SP has 2x more cathodes. -> 20% HV downtime. Anywhere along cathode vertical edge or endwall HV edge: FD-SP has 2x as many cathodes, 2x height. -> 40% HV downtime. Anywhere on cathode horizontal edge, or on horizontal FC or ground plane: FD-SP 10x length, 2x cathode or 2x width. -> 200% HV downtime. On beam plug. FD-SP has 0x as many beam plugs. -> 0% downtime.

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Replace NP04 camera 202 with PMT

Cameras 201, 202, and 203 are fisheye cameras installed in acrylic tubes that intrude into the cryostat from ports 14.2, 18.2, and 9.3 (resp.). They can be removed and replaced without draining the detector. Cam-202 is upstream beam right, near beam plug. Francesco: Replace camera tube 202 with a TPB-coated PMT. Acrylic is non UV-transparent, so entire tube must be removed,

• replaced. Some exposure of argon to air inevitable [unless some

kind of large “glove bag” can be rigged]. The PMT could be positioned to aim at the Top/Upstream/BeamLeft GP in the CPA surrounding with the possibly to rotate it from outside.

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View from Cam-202 before filling.

Upstream wall Beam right field cage and ground plane Endwall Beam plug

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Another photo, and Glenn’s sketch of Francesco’s idea

Photo (provided by Heng-Ye) of steel tube intrusion at bldg 182. Rotatable tube or

• ther structure

PMT TPB Beam right Beam left Beam plug

Not drawn to scale!

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More-directional UV detector using SiPM (Jim)

Tube lined with absorbing baffles. TPB-coated SiPM Aperture

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Rotate and tilt on fork with control rods

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Tiltable mirror design (MicroBooNE paper)

Mirror Camera and UV pinhole can look down to know well where we’re pointing

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Other miscellaneous thoughts so far

• For deployment: try large “glove bag” to prevent contamination. (Similar idea used

to prevent KamLAND contamination during camera viewport installation.)

• Could we put a UV-transparent acrylic dome on Cam-202 tube? Then mount

pinhole UV detector on conventional ethernet-controlled pan-tilt-zoom (PTZ) camera used as guide cam. Less complicated than mirror?

• Mirror: “Al+MgF2 is measured to have a specular reflectivity of ∼91% at argon

emission wavelength” -- https://arxiv.org/pdf/physics/0511093.pdf

• If we really need a 128-nm UV CCD camera, could one take an astronomical CCD

and coat it with TPB? (Commercial EUV-VUV-xray cameras exist, but all seem to have low QE right where we need it. Also horribly expensive)

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Pros, cons, and timeliness

• PMT: Pro: quick, not much R&D needed. Pro: large area, large sensitivity. Con: not

very directional.

• SiPM “pinhole camera”: Pro: quick, not much R&D needed. Pro: more directional.

Con: high directionality requires higher pointing accuracy, more raster scans. Con: small aperture means low flux sensitivity.

• Visible camera + pinhole UV schemes (mirror or PTZ camera mount): Pro: good

directionality and pointability, easier to have controlled raster scan. Con: low flux

• sensitivity. Con: more R&D needed, not quick.
• Multi-pixel UV camera: Pro: real imaging. Con: lots more R&D needed, could be

costly.

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