1. UCB Bialkali Cathode Process Program
Small window cathode development, 1.22” samples
Process samples to optimize QE and bandpass
Na2KSb, K2CsSb cathodes
Ready for cathode test run #6, shoot alkalis this week.
Testing B33, B33+ITO, B33+MgO/ITO substrates
Four sample holder
2 in process chamber
1 B33
2 B33+ITO
1 B33+ITO+MgO
in each
The sensitivity of the activated photocathode is considerably higher, with a quantum efficiency of as high as 37% at about 450 Å and a sensitivity cut off energy of about 6.2 eV. The observed decrease of sensitivity at 988 and 520 Å (and probably not observed at ~670 Å) is likely to correspond to 2xEgap+Eaff,, 4xEgap+Eaff,, and 3xEgap+Eaff,, respectively. A much better spectral continuity of the illumination source is required in order to study the UV absorption fine structure.

2. Antimony Beads Test Small sample test runs, 1.22”
Have SSL bead and new
Sb-Pt bead to test.
Substrate material tests
B33
ITO and MgO ALD layers
Preparing 6th run in small tank used to process Bialkali cathodes (1.22”). 2

3. 8” Tube Windows and Body Walls
The sensitivity of the activated photocathode is considerably higher, with a quantum efficiency of as high as 37% at about 450 Å and a sensitivity cut off energy of about 6.2 eV. The observed decrease of sensitivity at 988 and 520 Å (and probably not observed at ~670 Å) is likely to correspond to 2xEgap+Eaff,, 4xEgap+Eaff,, and 3xEgap+Eaff,, respectively. A much better spectral continuity of the illumination source is required in order to study the UV absorption fine structure.
We have a batch of 5mm thick B33 windows to use for seal tests
Latest Alumina tube body wall has been metalized and seems to be sufficiently flat
Need Indium wells so we can braze assembly then do seal tests