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Scientific Report 2007-2009
Laboratories and Facilities of the Department of Physics
L16. Electronics and Silicon detectors Lab
The Laboratory of electronics and silicon detectors is primarily
involved in the experiments of ultrarelativistic heavy ion and nuclear
physics with particle beams: ALICE experiment at CERN
and JLAB12 experiment at Jefferson Laboratory in the USA. The
Laboratory is also involved in the R&D activities for PET use
in medical applications with Silicon Photon Multiplier (SiPM)
detectors: AX-PET Collaboration at CERN and TOPEM Collaboration
in a R&D of INFN. In addition the Laboratory is
developing a Fast Photometer System based on silicon detector
SiPM for variable star measurements: collaboration with SCAE
group of our Department.
The instrumentation allows the Laboratory to develop electronics
on FPGA and allows testing FPGA and ASIC dedicated
to the reading of silicon detectors using a logic analyzer and Pattern
Generator both interfaced with a PC. A manual type Probe
Station allows the test on wafers with diameter up to 8” (see Figure
1). It is available a data acquisition system via VME to PC
Figure 1: 8” wafer in 0.25 micron CMOS thecnology
used for SDD ASIC in ALICE experiment.
using dedicated software (Labview). A climatic chamber allows tests on individual silicon detectors in the range between
10 ◦ C and 70 ◦ C with a current I = I(V ) measurement through Pico Ammeter. Finally, an optical pulsed system based on
LED allows their characterization in terms of response to short pulses (down to 0.9 ns).
http:www.roma1.infn.it/exp/alice
Related research activities: P8.
L17. SCILab
In the SCI-Laboratory have been developed, in
Collaboration with other Institutions and University
since 10 years several prototypes of particle
Detectors by collection of light emitted by scintillating
plates. To optimize the light collection efficiency
the Wave Length Shift fibers located on a
side of a plate or in a groove of a tile were extensively
studied. The Test results of these prototypes
were used to build the muon time stamp Detector
(CMP) and the Preshower Detector designed
to separate the electron/pion. Both Detectors were
installed into the 2 TeV Central Detector at Fermilab,
CDF, USA. Application of commercial photomultiplier
tubes with single anode or multi-anode
were investigate by different light readout to maximize
the amplification of the signal. Recently in
the Laboratory we have started Tests of the Silicon
Photomultipliers (SiPM),Fig. 1, for a new generation
of Calorimetry Detectors (FACTOR Experiment,
INFN ), Muon Detector (T995 Experiment
at FNAL) and track reconstruction of large zenith
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Figure 2: PMT signals (black and blue) of a muon track detected
by the telescope and digitized by the DRS4 with 2GS/s. The 1x1
mm 2 SiPM signal (green) detected by a tile insert in the telescope is
shown. The time difference between SiPM and PMT’s is due to length
difference of the cables. The telescope tiles are 10 cm apart along the
vertical axis.
angle atmospheric showers. The Laboratory is equipped with a DAQ chain that uses fast VME electronics: Time Digital
Converter with time resolution of few ps, Analog Digital Convertor to integrate the PMT signal, NIM Logic Units and a
GHz Pulse generator used for the characterization of the scintillators. To test the performances of the prototypes we use a
radioactive source ( 60 Co) or a muon telescope able to select cosmic rays. The telescope covers a solid angle of 1/64 stereo
radians and is equipped with a low threshold discriminator (5 mV) that provides a TTL/NIM trigger sent to a 6 GS/s
waveform Digitizing Board (DRS4) with 12 bit resolution, readout speed 30 MHz, jitter less than 100ps. The digitization is
transmitted by USB2 cable to a PC and analyzed by Linux software, Fig 1.
Related research activities: P9, P10, P11.
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SiPM
Sapienza Università di Roma 188 Dipartimento di Fisica