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Scientific Report 2007-2009<br />
Laboratories and Facilities of the Department of Physics<br />
L19. Laboratory of the KLOE-ROMA group<br />
The group of the Physics Department participates to the KLOE experiment at the DAΦNE e + e − collider of the Frascati<br />
Laboratories of INFN since 1992.<br />
Recently the group has been involved in the intense activity<br />
for the KLOE-2 experiment, which will start its data taking data<br />
in 2010 with an upgraded detector. One of the main improvements<br />
is a small angle electron and positron tagger, made by a<br />
pair of compact calorimeters, called low energy taggers (LET).<br />
These calorimeters are made of LYSO scintillating crystals and<br />
read-out by silicon photomultipliers, and the Roma group has<br />
the responsability of their design, construction, installation and<br />
test. Among the several activities, it can be mentioned the test<br />
of the scintillating properties of the LYSO crystals performed inside<br />
a black box with a small 137 Cs source with the experimental<br />
set-up shown in Fig.1. The same set-up using a LED as a light<br />
source has been used to test the performance of the silicon photomultipliers,<br />
and also of other kinds of photodetectors (e.g. high<br />
quantum efficiency photomultipliers for a preliminary study of Figure 1: The experimental set-up for the test of scintillating<br />
crystals and photodetectors.<br />
the KLOE upgrade.)<br />
Another activity of the group focused on the study of the response<br />
of the lead-scitillating fiber calorimeters to neutrons of<br />
kinetic energy in the range between 20 and 180 MeV. A prototype calorimeter realized in the Roma Laboratory has been<br />
successfully tested at the neutron beam of the TSL Laboratory of the Uppsala University (Sweden), showing an enhanced<br />
detection efficiency with respect to equivalent bulk scintillator counters.<br />
http://www.roma1.infn.it/exp/kloe/<br />
Related research activities: P19, P20, P21.<br />
L20. The ATLAS-KLOE-DREAM laboratory<br />
The laboratory has been used in the past to prepare and test detectors for the particle physics experiment KLOE at the<br />
e+e- collider DAPHNE of the INFN Laboratori Nazionali di Frascati and for the experiment ATLAS at the LHC accelerator<br />
at CERN. In the next future some tests will be performed for the DREAM Collaboration studying a new approach (dual<br />
read out) to optimize hadronic calorimetry in high energy experiments.<br />
For the KLOE experiment in the laboratory has been prepared a small prototype of the big central chamber<br />
before moving that in a test beam at CERN, where a full test of<br />
this drift chamber, operated with a helium - isobuthane mixture,<br />
has been performed also in a magnetic field. This small detector<br />
served also to study the final configuration of the wires in the<br />
chamber of the KLOE detector. For ATLAS in the laboratory<br />
has been prepared and operated the system used to test about<br />
15000 drift tubes before they were assembled in the chambers,<br />
built in Rome, for muon detection in the big spectrometer of<br />
the experiment. The system is visible in the figure. For each<br />
tube the mechanical wire tension and the leakage current in<br />
HV (3080 V for a 4 × 10 4 gain at the wire) were measured. An<br />
accurate system checked the wire off-centerig in the tube with a<br />
10 microns rms in projection. Also the gas leak of the tubes was<br />
measured (gas leaks smaller than 10 −8 bar liter/s at 3 absolute<br />
Figure 2: The system for the test of the drift tubes for<br />
bars were required). All these tests were controlled by a computer.<br />
A non invasive technique to replace broken wires in drift<br />
the muon chambers of ATLAS.<br />
tubes glued in the chambers was then developed in this laboratory and used in other laboratories of the ATLAS Collaboration.<br />
Related research activities: P1, P2, P3, P19, P20, P21.<br />
<strong>Sapienza</strong> Università di Roma 190 Dipartimento di Fisica