Speakers
Francesco Cafagna
(Universita e INFN, Bari (IT))
Michele Quinto
(Universita e INFN-Bari (IT))
Description
To further extend the measurement potentialities for the experiment at
luminosities where the pile-up and multiple tracks in the proton
detectors make it difficult to identify and disentangle real
diffractive events from other event topologies, TOTEM has proposed
to add a timing measurement capability to measure the
time-of-flight difference between the two outgoing protons.
For such a precise timing measurements, a clock distribution system that
empowers time information at spatially separate points with picosecond
range precision, is needed.
For the clock distribution task, TOTEM will adopt an adaptation of the
Universal Picosecond Timing System,
developed for the FAIR (Facility for Antiproton and Ion Research)
facility at GSI, actually installed as BUTIS system.
In this system an optical network, using dense wavelength division
multiplex (DWDM) technique, is used to transmit two reference clock
signals from the counting room to a grid of receivers in the
tunnel. To these clocks another signal is added that is reflected back
and used to continuously measure the delays of every optical
transmission line; these delay measurements will be used to correct the
time information generated at the detector location.
The usage of the DWDM make it possible to transmit multiple signals
generated with different wavelengths, over a common single mode
fibers. Moreover allows to employ standard telecommunication modules
conform to international standards like the ITU (International
Telecommunications Union) ones.
The prototype of this system, showed that the influence of the
transmition system on the jitter is negligible and that the total
jitter of the clock transmission, is practically due to the inherent
jitter of clock sources and the end user electronics.
By the time of the Conference, the system will be commissioned in the interaction point 5 (IP5) TOTEM control room. Details on the system design, tests and characterization, will be given in this contribution.
Authors
Francesco Cafagna
(Universita e INFN, Bari (IT))
Michele Quinto
(Universita e INFN-Bari (IT))
