gain’effects’for’ald’mgocoated’ mcps’gain$map$histogram$in$xshows$leu$side$has$...
TRANSCRIPT
Standard MCP, a,er a MgO ALD deposi7on on one half
The MgO coated area is clear on one side, but oxidized on the other (there is NO NiCr on top of the MgO).
Gain Effects for ALD MgO Coated MCPs Standard MCP + scrubbing. Borosilicate MCP pairs:-‐ UHV bake and scrub, scrub without bake.
1
10
100
1000
750 800 850 900 950 1000 1050 1100
Gain
Gain
Gai
nMCP Voltage
3.2 nA input0.5 nA input
The gain curve uncoated is comparable with other standard MCPs. Note that with the higher input signal the MCP saturates when too much current is drawn.
Bare MCP gain curve
1050v on standard MCP, 1050v on #161MCP The MgO coated area is unresponsive (there is NO NiCr on top of the MgO), the MgO coated area has low QE, -‐ absorbs the UV strongly.
On front -‐ standard MCP + half ALD MgO. On front -‐ #161 ALD MCP Behind -‐ #161 ALD MCP. Behind -‐ standard MCP + half ALD MgO. 200v over 0.75mm gap between MCPs. 200v over 0.75mm gap between MCPs.
GAIN MAP FLUX IMAGE
1050v on standard MCP, 1050v on #161MCP
The MgO coated area has much less gain than the uncoated MCP, by a factor of 5.
Gain map histogram in X shows leU side has gain 2x the right side, and right side is ~ same as bare MCP. So gain increases by x10 aUer annealing.
GAIN MAP
On front #161 ALD MCP, standard MCP with half ALD MgO behind, 200v over 0.75mm gap between MCPs.
1050v on front #161 MCP, 1050v on standard MCP
The #161 provides 200v electrons to the MgO coated MCP.
AFTER ANNEALING
GAIN MAPS
On front #161 ALD MCP, standard MCP with half ALD MgO behind, 200v over 0.75mm gap between MCPs.
1050v on front #161 MCP, 1050v on standard MCP
AFTER ANNEALING
0 Coul cm-‐2 0.000045 Coul cm-‐2 0.0011 Coul cm-‐2 0.0074 Coul cm-‐2 0.01 Coul cm-‐2
The thick MgO (leU half) starts out 2x the gain of the very thin MgO (right half), degrades to the same value then progressively increases to ~8x the gain of the right half. Normal MCP would have dropped gain by x3 by 0.01 Coul cm-‐2.
0.022 Coul cm-‐2 0.036 Coul cm-‐2 0.057 Coul cm-‐2 0
5 106
1 107
1.5 107
2 107
2.5 107
0 0.01 0.02 0.03 0.04 0.05 0.06
Gai
n
Extracted Charge (C cm-2)
On front #11863-‐097(serial #180) + #12317-‐141 behind, 200v over 0.75mm gap between MCPs. Scrub with no bake. Test sequence:-‐ Test gain Scrub 0.01 C cm-‐2, retest gain Up to air for 5 min, pump down, retest gain Scrub 0.04 C cm-‐2, retest gain Unpumped for 2 months (poor vacuum), Pump down, retest gain Scrub 0.048 C cm-‐2, retest gain
Indicates that the gain rises by x2 over 0.05C cm-‐2 from ini]al value which is already 2x standard MCP. Even with air exposures.
On front #164 + #163 behind, 0.001” gap between MCPs. UHV bake and then long term scrub.
101
102
0 1 2 3 4 5 6 7
25µm pair 40:1b25um Pair 40:1a6µm pair 80:1 164-163 Lifetest613-612 Lifetest
Gain
(re
lativ
e)
Extracted Charge (C cm-2)
103
104
105
106
107
108
0 1 2 3 4 5 6 7 8
2000 V1750 V1450 V1300 V
Gain
Extracted Charge (C cm-2)
0.1
10
1000
105
107
800 1000 1200 1400 1600 1800 2000
Post N2 ExposurePre N2 Exposure
Gai
n
MCP Pair Voltage
Gain curve rises by x10 during 350°C Vacuum bake.
7C cm-‐2 charge Extrac]on at 105 gain shows small gain decrease.
Gain stability During scrub is excellent at gain of ~ 2 x 106
Gain stability on re-‐exposure to dry N2 for 15 min very good.