Masked strips in reconstruction

RPC­DPG Latest Results
Camilo Carrillo
on behalf of
RPC Trigger Group.
Departamento de Física
UNIVERSIDAD DE LOS ANDES
Bogotá, Colombia
CMS Week, September 2008
Muon DPG­POG Meeting

• RPC System.
Outline
• Synchronization status.
• RPC Noise studies.
• RPC Efficiency.
• Simulation / Reclusterization.
• Conclusions

Full barrel and positive endcap (RE+1 & RE+3 ) in read out
Occupancy plots (from DQM):
RPC System
One noisy chamber in this sector.
10/12 trigger crate in operation: power supplies missing.

Gas system stable : fresh injection about 10 %
Current monitor of one chamber
over one month
RPC Gas
Purifiers: automatic change over takes place without problem
Gas Flow (in and out ) monitor of
one channel over one month
Analysis module (O 2+H 2O): gas mixture is automatically analyzing before and after
the purifiers.
Gas chromatograph working fine (at the moment it is in reparation)

Synchronization

Synchronization

Noise Studies
A tool for identification of noisy strips in a
given chamber.

RPC Efficiency Segment
Same wheel and Same Sector.
For RB1, we extrapolate from MB1
For RB2 we extrapolate from MB2
For RB3 we extrapolate from MB3
For RB4 we extrapolate from MB3
and MB4
Extrapolation.
DT CSC
All DT Chambers.
For RPCs in Ring 2 we extrapolate from
Same Ring and Same Station (Disk) of
CSCs.
For RPCs in Ring 3 we extrapolate from
Same Station (Disk) but always Ring 2
of CSCs
We don't use Station 4 nor Ring 1 of CSCs

Run 58555
Event 5708904

Other view for the same Event

HV Scan with DT Segment
Extrapolation

HV Scan for W+1 Near Side
(Average Efficiency)

Simulation
The RPC simulation, since may, has reached the maximum
level of the details concerning noise and efficiency.
Maps containing the informations concerning the noise and
efficiency, strip by strip, can be loaded and used to digitize
the simulated hits. An object in ORCOFF is stored
permanently with a proper IOV.
Therefore in principle the simulation could be always
upgraded with the results coming from the prompt analysis.
This will become a standard procedure when the efficiency
will be estimated. In order to perform this upgrade the
simulation package need only the new files uploaded in
ORCOFF.

Simulation
• The previous way to run the simulation (reading from
ORCOFF) allows to get results comparable with the real
situation.
• However it didn’t allow to perform any forecast about the
influence of different parameter detectors on the L1 RPC
trigger performance.
• Files similar to the ones stored in ORCOFF are available to the
user, in order to change values of noise and efficiency of the
conditions in the wished way.
• This is crucial for the next complete study of the RPC Trigger
performance in the Barrel, but specially in the Forward part, in
order to understand the effect of noise.

RECLUSTERIZATION
• At the moment no information about noise is stored in
the ORCON/ORCOFF data bases.
• In particular, there is no information about noisy strips
that are masked.
• Currently the masked­strip information is not used in
reconstruction.
• The software to take masked strips into account is being
produced.

Masked­strip information
• The masked­strip information should be in the ORCOFF
data base in the future . In order to do this a payload
application is needed.
• In the meanwhile it will use only the fake condition stored
by means of dat file in the package
Calibration/RPCCalibration. A file called
RPCMaskedStrips.dat.
• The file will contain for each RPC roll: the RPCDetId, the
raw Id, and a list of 96 bits (“0” or “1”).
• The file is read out in the constructor of the
RPCRecHitProducer class and stored in an RPCDetId
→ RollMask map

Mask re­clusterization
• Until now If there is a masked strip between two clusters,
the two clusters remain separate.
• For the clusterization process it will be assumed that the
masked strip between two clusters had a hit, and the two
clusters will be merged.
• The software should look for clusters separated by a
masked strip, and merge them.

Mask re­clusterization
implementation
• A new class called RPCMaskReClusterizer has been
created inside the RecoLocalMuon/RPCRecHit package:
const int SIZE=96;
typedef std::bitset RollMask;
class RPCMaskReClusterizer
{
public :
};
RPCMaskReClusterizer();
~RPCMaskReClusterizer();
RPCClusterContainer doAction(const RPCDetId& ,RPCClusterContainer& , const RollMask& );
int get(const RollMask& ,int );

Reclusterization procedure
• The existing Clusterizer in the RPCRecHit package
produces a cluster container out of an
RPCDigiCollection.
• The ReClusterizer takes that cluster container and
produces a new cluster container after reclusterization.
• The ReClusterization algorithm is identical to the
Clusterization one, only the condition for merging
clusters changes from:
Adjacent clusters
→
A masked strip between two clusters

Conclusions
� The RPC system for the Barrel, RE+1 and
RE+3 are in readouts.
� RPC Gas System working in closed loop,
10% of fresh injection.
� Tools for monitoring up to strips level
(maximum granularity level) efficiency and
noise have been developed.

Conclusions
• More realistic simulations are coming
taking into account the parameters of the
detector.
• Improvements about the reconstructed
RPC Hits are under construction.
• HV Scan done for the near side in the
Barrel.
• RPC Efficiency tool looking forward for
collisions.