ArgoYBJ: further steps for the next thfuture WAPP 2009 Bose Institute, Mayapuri, Darjeeling Dec 12 th 2009 By R. Santonico.
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ArgoYBJ: further steps for the next thfuture
WAPP 2009Bose Institute, Mayapuri, Darjeeling
Dec 12th 2009By R. Santonico
Argo is an unprecedented combination of:
• Large detection area (about 7000 m2 of RPCs)• Full coverage (92%)• High granularity (about 150000 read out strips)• High time resolution (2 ns)• High altitude (YBJ 4300 m asl)
His purpose is to image the shower front and to lower the threshold energy to a few hundreds GeV
10 Pads = 1 RPC (2.80 1.25 m2)
Gas Mixture: Ar/ Iso/TFE = 15/10/75
78 m
99 m
74 m
111 m
RPC 5600 m2 ( 92% active surface)• sampling guard-ring
Central Carpet:130 Clusters
1560 RPCs
124800 Strips
BIGPAD 1
ADC
RPC
Read-out of the charge induced on
“Big-Pads”
12 RPC =1 Cluster ( 5.7 7.6 m2 )
8 Strips = 1 Pad (56 62 cm2)
BIGPAD2
The ARGO-YBJ detector
Main improvement items: on the analysis
An unprecedented detector requires an unprecedented approach to the analysis
• Shower front reconstruction:- Usually made by fitting the shower front with a conical surface- Can we do better eg using a parabolic surface o fit the front? - Crucial improvement for a good direction reconstruction of very
low energy primaries (20-30 hits below 1 TeV)• Gamma-hadron discrimination- Not implemented so far in the analysis- Crucial for the γ-ray astrophysics- A strong effort has to be invested to exploit the potential of
Argo for the γ/h discrimination
Galactic plane
HESS J1841-055
CRAB
MGRO J2031+41
PSR J2021+4026
542 days
2007 day 311–2009 day 220
nhit > 40 Smoothing window radius = 1.3°
Percent variation542 days
2007 day 311–2009 day 220
Moon shadow: all data (2006+2007+2008)
N > 6043 s.d.
9 standard deviations / month
PSF of the detector
2063 hours on-source
θ < 50°
Main improvement items: on the detector
• Analog read out- Allows to study the shower core details in the meter
scale- Extends the multiplicity measurements up to densities
of several thousend particles per m2• Use radio wave detecting antennas- to complement the information supplied by the RPC
carpet with radio signals emitted by cosmic showers-
E 100 TeV
Strip Big Pad
E 1000 TeVStrip
Big Pad
A radio wave antenna for Argo
• Radio wave signals generated by Extensive Air Showers are random signals of limited duration and wide frequency band
• They are not easy to be detected by standard “resonating” antennas
• “Progressive wave” antennas being intrinsically wide band seem to be particularly suitable for their detection
• A prototype antenna of this kind was tested at YBJ
Argo “big pad” signal vs Antenna signal and its FFT
Next steps
• The noise below 20 MHz is now well filtered in the prototype antenna
• A trigger channel searching for coincidences with the RPC carpet will be stably implemented at the beginning of 2010
• Crucial to understand what role the antenna can have for a low energy oriented detector like Argo
Conclusions
• An improvement of the analysis methods will allow Argo to fully express its scientific potential
• The multiplicity analog read out is extremely promising to study dense shower cores in detail
• The complementation of the RPC carpet with a radio wave antenna might open a new horizon
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