LHC LUMINOSITY (RATE) MONITORS LBNL is responsible for the design and production of the TAS and TAN absorbers for IP1 and IP5. Bill Turner of LBNL has proposed to put some kind of instrumentation in these absorbers in order to measure the luminosity (or better the relative interaction rate.) After a number of iterations the decision was to instrument only the TAN's in IP1 and IP5, but also to install the same kind of monitors in IP2 and IP8. Two kind of technologies are under study for the detectors Ionization Chamber (most probable choice) CdTe solid state detectors In IP2 and IP8 there are no TAN's and an absorber must be put in front of the detectors in order to generate the showers (3cm of Cu for CdTe and 30cm of Cu for the IC)

Beam setup at IP5 (CMS)

LUMINOSITY MONITORS IN IP2 In IP 2 the place where the “fake TAN's” would have been installed is taken by the Zero Degree Calorimeters (ZDC's.) Massimo Placidi had some contact with the ALICE people, and at that time it seamed reasonable to put 3cm of Cu in front of the ZDC's, however the integration of the two systems was not discussed. Seen that the preferred choice for IP1 and IP5 is the IC and that the IC requires 30 cm of Cu a different solution has to be found. One possibility would be to put the Luminosity monitors after the ZDC's, they will still be usable when the ZDC's are retracted (high lumi p-p runs and beam setup's), which in fact are the occasions where the luminometers are most required.

Integration of the luminometers in LHC In point 1 (ATLAS) and 5 (CMS) there are no problem since they will be inserted inside the TAN and Berkeley knows very well this devices since they built them. (ZDC's for CMS and ATLAS too??) For IP2 a first contact with Daniela Macina was established last week and seen that the ZDC's beam line is already being designed this issue becomes extremely urgent. For IP8 there is nothing going on yet but a contact with the LHC-b experiment must be established as soon as possible too.

The Ionization Chamber

The CdTe detector