Data Format GRAAL

VARIABLE	TIGER EVT RECON correspondence	DEFINITION	COMMENT
Event	evtNo	event ID from 0 to total number of event
nGemHit		number of good hits in one event
GemHit_nHit		same as nGemHit
GemHit_nHit_view		array of number of good hits for each view in one event
GemHit_nHit_bad		number of bad hits in one event
GemHit_channel	tchannel	channel ID from 0 to 63 readed by TIGER
GemHit_chip	chip	chip ID	from 0 to 87
GemHit_ROC	tgemroc	GEMROC ID readed by TIGER
GemHit_FEB	tFEB_label	FEB label from 0 to 43 (L1 + L2) defined from mapping	from 0 to 43
GemHit_plane		hit plane	(0=L1, 1=upper L2, 2=lower L2)
GemHit_view		hit view	(2 = Phi, 3 = V)
GemHit_strip	tstrip_v	tstrip_x	strip ID from mapping as a function of channel and FEB
GemHit_q	tcharge_SH	efine of the hit readed by TIGER + calibration from FEB
GemHit_x		coordinate of the strip (in radiant if Phi, else in mm)
GemHit_pos		hit position in X reference frame
GemHit_z		hit position in Z reference frame	Z is minus the beam direction
GemHit_time	t_min_ttrigg	hit time from the trigger time
nGemCluster		number of cluster of hits in one event
GemCluster1d_nCluster		same as nGemCluster
GemCluster1d_plane		cluster plane	(0=L1, 1=upper L2, 2=lower L2)
GemCluster1d_view		(2 = Phi, 3 = V)
GemCluster1d_q		cluster charge in fC as sum of hits charge
GemCluster1d_x		coordinate of the cluster (in radiant if V, else in mm) in CC no TPC yet
GemCluster1d_z		cluster position in Z reference Z is minus the beam direction
GemCluster1d_pos		cluster position in X reference

GRAAL analysis procedure

GRAAL analysis is divided in three parts: reconstruction, tracking and analysis.

1) Reconstruciton: creates hits from the TIGER data and it clusterizes contiguous hits

2) Tracking: look for the best cluster for each detector and it measures the particle path and the residual distribution of the detector to this track

3) Studies the performance of the detector and of the cluster with a good residual distribution

Reconstruction:

-- Digitization --

Starting from the information of the output of TIGER Reconstruction Event (event.root) is associate to each collected signal the variables reported above.

The cut on the hits are the following:

Strip > 0 -> strpis are initialized to -1 and if there are problems this cut removes the hits if it is not properly filled

View > 0 -> views are initialized to -1

Channel != TP_Channel

Charge > 0.5 fC

-100 < Time < 150 ns

Remove noisy channel labelled here (chip,channel) --> (43,3), (46,26), (73,3), (87,45)

-- Clustering --

Contiguous strips are collected together where

Q_cluster = sum Q_hit

X_cc = charge centroid position

Tracking:

If cosmics run is analyzed then it divides L1 and L2 in three planes: top L2, bottom L2 and L1.

The two sides of L2 are used as tracking system. The cluster with higher charge is selected as the good one and a linear fit is performed with the two points.

If L2 top and L2 bottom are not firing at the same time then the track is not reconstructed.