LABM at SuperKEKB (KEK, Puebla, Sinaloa, Tabuk, WSU) G. Bonvicini, S. Di Carlo The work on Large Angle Beamstrahlung Monitor is conducting at LEPP on CESR by WSU group and supported by NSF grant

LABM installation and commissioning completed Jan LABM installation and commissioning completed Jan. 20, 2016 (32 PMTs, 4 viewports) http://motor1.physics.wayne.edu/~fj0465/labm/home.html Optical Channels Oho side. Detector is quiet and dark. PMT and optical components efficiency measured in situ Integral over ten years

Data obtained with first beam (LER/Nikko side) Red= LER current, blue= PMT rate PMT rate versus beam current

Angular scans Phase I detector has 4 viewports, with 2 polarizations, and 3-band spectral information (1 PMT used as control for each sub-spectrometer). Started with wide open collimators (19mm) Expect to see (0,0) peak from last bend, preminent, unpolarized, and with flat spectrum Reflections off Beam Pipe expected from general direction of IP Angular structure seen in all 8 sub-spectrometers. Backgrounds are present due to lack of SR masks during Phase I.

Oho Down (L: Pol-x, R, Pol-y, range about 23X23 mrad2, 12 mrad collimators)

Nikko Down (L: Pol-x, R, Pol-y, range about 23X23 mrad2, 19mm collimators)

Status and to do Primary and reflection peaks clearly seen. They are all along nominal vertical line. Reflections represent main backgrounds in direction of IP. They are as expected broader, less intense, redder (TiN reflectivity very similar to copper), and strongly x-polarized. As such, they can be subtracted statistically Go to 8mm collimators (another order of magnitude background reduction and sharper peak definition) at next access (3/10). Improve scanning software (correlated primary and secondary mirror motions), prepare software for data analysis if collisions are given.