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The RPC charge Read-Out system of the ARGO-YBJ detector. S. Mastroianni INFN sez. di Napoli On behalf of the ARGO-YBJ Collaboration. Collaboration Institutes: Chinese Academy of Science (CAS) Istituto Nazionale di Fisica Nucleare (INFN).
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The RPC charge Read-Out system of the ARGO-YBJ detector S. Mastroianni INFN sez. di Napoli On behalf of the ARGO-YBJ Collaboration • Collaboration Institutes: • Chinese Academy of Science (CAS) • Istituto Nazionale di Fisica Nucleare (INFN) • ARGO-YBJ is a cosmic ray air shower detector based on a single layer of RPC covering a total instrumented area of ~ 10,000 m2 • High altitude site (YBJ, 4300 m a.s.l.) • Layer of RPC covering 5800 m2 ( 92% active surface) with 0.5 cm lead converter + sampling guard ring • Central Carpet: 130 Clusters, 1560 RPCs, 124800 Strips • High space-time resolution (time1 ns; space (strip) 6.5 ×62 cm2) • In stable data taking since Nov. 2007 (d.c. > 90%) • Low Multiplicity trigger with 20 fired pads on the central carpet • Trigger rate ~ 3.7 kHz, dead time ~ 4%, data acq. rate 3 MB/s; • Aims: • cosmic-ray physics (~1 TeV a few PeV) • VHE γ-astronomy (above ~300 GeV) Detector Longitude 90° 31’ 50” East Latitude 30° 06’ 38” North 4300 m above the sea level 90 Km North from Lhasa (Tibet) To investigate the PeV energy region, we must have the ability to detect air showers with a secondary charged particles density of ~ 103 particles/m2 the charge read out has been implemented by instrumenting each RPC with two Big Pads (BP 140125 cm2 ) 1 Cluster = 24 BPs ~1.7103particles/BigPad BigPad dens 1000/m2 STRIP dens 22/m2 Saturation of digital read out S. Mastroianni - 17th Real-Time Conference, Lisboa, Portugal
The Charge Meter system Duration: > 10ms Rise Time : 20-30 ns Amplitude mV40 V • The charge read-out system is based on a custom crate (MINICRATE) • - two independent sections each one manages 24 BP signals form Cluster module • 3 Charge Meter cards • 1 Control Module for the data read-out • Input signal adapted to 50 Ω with a coaxial cable (12.5 m, attenuation of ~ 5%) • a voltage filter cuts out spikes greater than 40 V • linear amplifier with variable gain (VGA: 0.33, 0.66, 1.3, 2.5, 5, 10, 20 and 40 V) • constant fraction amplifier cuts the long tail of the input signal in order to realize the coincidences on the same shower (in about 500 ns); • Peak&Hold with a tilt time of 4mV/μs, for 2 μs. • ADC digitalization within 1.4 μs • data collection managed via a custom bus protocol operated on the backplane lines. Typical m.i.p. signals in the Big Pad with the detector operated at 9.5 kV with a gas mixture made of 15% Ar, 10% I-C4H10 and 75% R143a. Rise time ~ 20-30 ns, Amplitude mV tens of Volts; duration ~ 10 μs Filter/Linear Amplifier/ Shaper/Peak&Hold/12-bit ADC/Buffer Conversion enabled by a local density trigger (16, 32, 64 hit particles for Cluster) The data read-out is managed by the Control Module that provides an interface with the Trigger and the main DAQ systems …. and each Control Module is connected in a daisy-chain network (link of 1Mbit/s) for control and monitoring purposes handles the calibration (~ 4000 BPs on a very huge surface with an extreme variation of the environmental parameters) by means of a 12-bit DAC on each CM board. S. Mastroianni - 17th Real-Time Conference, Lisboa, Portugal
The Event selection ~ Contained events The central carpet (130 Clusters) has been instrumented with all the charge read-out electronics at the YangBaJing Laboratory since November 2009. The gain of the electronics was set at he moment in order to operate in the amplitude range 0-300 mV of the input signals allowing the overlap between digital and analog readout which is another way to calibrate the analog system. Three local trigger configurations were successfully tested (16,32 and 64 particles on at least one Cluster). In about six months of data taking, a few ten million showers have been reconstructed with the analog system. Central carpet saturated ~ localized event Test results and data recorded by the charge read-out system confirm the design expectations, thus the ARGO-YBJ capability to operate at a very high particle density (> 103 particles/m2). S. Mastroianni - 17th Real-Time Conference, Lisboa, Portugal
Thank you for your attention! POSTER –PDAQ 26 S. Mastroianni - 17th Real-Time Conference, Lisboa, Portugal