Scintillating Fiber Hodoscope for Bremstrahlung Luminosity Monitor
Abstract
The performance of a scintillating fiber (2mm diameter) position sensitive detector (4.8 × 4.8 cm^2 active area) for the luminosity monitor (LMPSD) at the VEPP-2M electron-positron collider at the Budker Institute of Nuclear Physics in Novosibirsk, Russia is described. Custom electronics is triggered by coincident hits in the X and Y planes of 24 fibers each, and reduces the 64 channel photomultiplier signals (one for each 25 cm long fiber) to a 10 bit (X,Y) address. These hits are accumulated in a CAMAC memory register at 10 kHz and provide a real time 2D display of the VEPP-2M collision vertex in the control room every few seconds. The width of the strongly peaked distribution ( ~ 3-4 mm at 1.6m from the E_beam = 500 MeV collision vertex of VEPP-2M ) is used to measure the angular distribution of single bremstrahlung photons incident on a BGO crystal luminosity monitor. Subtracting the expected QED angular distribution fit from the data yields a background which is in agreement with an independent determination of the VEPP-2M luminosity.
- Publication:
-
APS Meeting Abstracts
- Pub Date:
- May 1996
- Bibcode:
- 1996APS..MAY..J908B