The document provides an overview of the HADES RPC ToF Wall cosmic ray commissioning project. It discusses (1) the instrumentation of the 6 RPC sectors and initial cosmic ray testing, (2) the collection of approximately 50 days of cosmic ray data totaling 895 GB, and (3) preliminary analysis of cosmic ray tracks using the TimTrack algorithm, including reconstructed position and time results. The aim is to validate the RPC detector performance before data taking with particle beams begins.

1. The HADES RPC Cosmic Ray Telescope:
Preliminary Analysis
Pablo Cabanelas
Laboratorio Carmen Fernández, USC
Proyecto
2nd Workshop, Compostela, February 2010

2. OUTLINE:
● Overview of the HADES RPC ToF Wall
● The Cosmic Ray Commissioning
● Close to the first TRASGO
● Preliminary Analysis Results

3. RPC

4. The HADES RPC ToF Wall
Consist on 1122 shielded 4-gap timing RPC cells
(0.280mm/gap), covering about 8m2, distributed like this:
● 6 almost-identical sectors
● 2 RPC layers per sector
● 3 columns of RPC cells per layer
● 31 RPC cells per column

5. The RPC Commissioning
From April 2009 to nowadays
1. The 6 sectors were instrumented by pairs at the
GSI and placed at horizontal position.
2. Cosmic Ray test was performed with such a
setup.
3. At the end, they were mounted on their nominal
position in HADES.
4. Currently, they are just there, a bit bored,
waiting for a beam to take data.

13. Hit distribution of cosmic rays over the 6 RPC sectors

14. Cosmic ray commissioning summary:
● 6 RPC sectors fully instrumented, tested,
validated and mounted in HADES
● About 50 days of data taken at a rate of 200
Hz over a pair of sectors
● 895 Gb of data stored
● 1122 RPC cells operative as well as 2243
channels (all but one!)

15. Preliminary Cosmic Ray Analysis with TimTrack
Proyecto
timtrack
timtrack
timtrack timtrack
timtrack A Tracking Algorithm for
timtrack TRASGOS
timtrack Already introduced
timtrack
timtrack To be presented by
timtrack J.Garzón
ttrack
tim
imtrack

16. TimTrack: L
x
z
X’ V
X0 T0
Vz
z=0 Y’
Y0 y

17. Preliminary Cosmic Ray Analysis with TimTrack
Analyzed events crossing
one set of four RPC cells
~42cm
~5cm
33cm
Ref Plane
Z
X

18. Preliminary Cosmic Ray Analysis with TimTrack
Some Ultra-Preliminary Results!!!
Reconstructed X at the
reference plane
Reconstructed X vs X' (slope):
acceptance

19. Preliminary Cosmic Ray Analysis with TimTrack
Some Ultra-Preliminary Results!!!
~6-8 ns
Two-Peak
structure
Reconstructed T0 (Time at the reference
plane) in ps [Not calibrated]

20. Close to the first TRASGO ??
2 HADES RPC sectors:
TRASGO:
Four planes of shielded 4-
Several planes (4 at least)
gap RPCs
of ?-gap RPC strips
Different Geometry -- Same FEE, DAQ and Analysis