Space Sciences Laboratory, University of California, BerkeleySSL-UCB, ALD MCP Test Progress

ML201-B-2 12nm ALD

After cleaning

After cleaning

ML201-B-1 6nm ALD

Space Sciences Laboratory, University of California, Berkeley

Initial Imaging Results on Standard MCPswith 6nm ALD coating, single MCP, phosphor

1150v MCP, 2800v Screen, UV floodPhotonis ML201-B-1 MCP, 86MΩ

1050v MCP, 2900v Screen, UV floodPhotonis ML201-B-1 MCP, 86MΩ

Shows definite enhancement of brightness in ALD area, due to GAIN increase!No degradation of image quality, except at the boundary zone for coating

ALDALD

No ALDNo ALD

Space Sciences Laboratory, University of California, Berkeley

1100v MCP, 2700v Screen, UV floodPhotonis ML201-B-2 MCP, 90MΩ

Shows definite suppression of brightness in ALD area, UV QE reduction!No degradation of image quality, except at the boundary zone for coating

ALD

No ALD

Initial Photon Counting Resultswith 12nm ALD coating, single MCP, phosphor

Space Sciences Laboratory, University of California, Berkeley

Initial Photon Counting on Standard MCPsStacked as a pair with 6nm/12nm ALD coating

2400v MCPs, UV flood, MCP pair,Photonis ML201-B-1 (6nm) top, ML201-B-2 bottom (12nm)

2400v MCPs, UV flood, MCP pair,Photonis ML201-B-1 (6nm) top, ML201-B-2 bottom (12nm)

GAIN MAP IMAGE

6 nm/12 nm

6 nm/0 nm

0 nm/0 nm

0 nm/12 nm

6 nm/12 nm

6 nm/0 nm

0 nm/0 nm

0 nm/12 nm

Using our photon counting imaging detector (25mm cross delay line) we stacked the ALDcoated MCPs in a pair, 6nm on top, 12nm underneath, with the ALD layers rotated to givefour combinations of MCP configurations.

Legend:-

?? nm/ ?? nm

Top MCP / bottom MCP

Space Sciences Laboratory, University of California, Berkeley

Initial Photon Counting Results on Standard MCPsNormal uncoated MCP area,

BUT - low UV response due to small events being electronically rejected!

6 nm/12 nm

6 nm/0 nm

0 nm/0 nm

0 nm/12 nm

12 nm coated MCP area under uncoated MCP,

higher UV response due

to higher gain - norejected events.

6nm coated MCP over uncoated MCP, - low UV response due to ALD coating suppressing nichrome photoemission!

6nm coated MCP over 12nm coated MCP, - low UV response due to ALD coating suppressing the nichrome photoemission!

IMAGING

Space Sciences Laboratory, University of California, Berkeley

Initial Photon Counting Results on Standard MCPs

6 nm/12 nm

6 nm/0 nm

0 nm/0 nm

0 nm/12 nm

12 nm MCP under uncoated MCP

is 3.5x higher UV QE than 6nm coated on top of 12nm MCP

uncoated MCPs are 1.5x higher

UV QE than 6nm coated MCP on top of uncoated MCP

Image MAP Histograms

Space Sciences Laboratory, University of California, Berkeley

6 nm/12 nm

6 nm/0 nm

0 nm/0 nm

0 nm/12 nm

Initial Photon Counting Results on Standard MCPs

Normal uncoated MCP area,

Lowest gain!

12 nm coated MCP area under uncoated MCP,- moderate gain increase.

6nm coated MCP over uncoated MCP, - moderate gain increase!

6nm coated MCP over 12nm coated MCP, - big gain increase!

GAIN MAP

Average gain is about 5 x 106

Space Sciences Laboratory, University of California, Berkeley

Initial Photon Counting Results on Standard MCPs

6 nm/12 nm

0 nm/0 nm

0 nm/12 nm

6 nm/0 nm

GAIN MAP Histograms

6nm on top or 12 nm under

Gives similar gain enhancement

6nm on top gives x2 gain enhancement

6nm on top of 12nm gives x2 gain enhancement

6nm on top plus 12 nm under

gives >4x gain enhancement

Space Sciences Laboratory, University of California, Berkeley

Initial Photon Counting Results on Standard MCPsStacked as a pair with 6nm/12nm ALD coating

Summary• ALD Al2O3 coatings decrease the UV efficiency significantly

• Need to put ALD under the electrode if we want UV QE

• ALD Al2O3 coatings increase the MCP gain significantly

• Both top and bottom MCP coatings are beneficial

• ALD Al2O3 coatings don’t seem to affect the imaging quality

• Still to do• Consequences for background rates?• Wider range of applied voltages/gains• More detailed imaging performance issues• Scrubbing and thermal ramifications