Sep 25 – 29, 2006
Valencia, Spain
Europe/Zurich timezone

Integration of the CMS regional calorimeter Trigger hardware into the CMS level-1 Trigger

Sep 26, 2006, 10:55 AM
Valencia, Spain

Valencia, Spain

IFIC – Instituto de Fisica Corpuscular Edificio Institutos de Investgación Apartado de Correos 22085 E-46071 València SPAIN


Pamela Klabbers (University of Wisconsin)


The electronics for the Regional Calorimeter Trigger (RCT) of the Compact Muon Solenoid Experiment (CMS) have been produced and tested. The RCT hardware consists of 18 double-sided crates containing custom boards, ASICs, and backplanes. The RCT receives 8 bit energies and a data quality bit from the HCAL and ECAL Trigger Primitive Generators (TPGs) and sends it to the CMS Global Calorimeter Trigger after processing. Before installation, integration tests were performed. Data was successfully received from the TPG electronics and read out with a RCT Jet Capture Card. These tests, other tests involving more trigger subsystems, their results, and the RCT installation will be described.


The electronics for the Regional Calorimeter Trigger (RCT) of
the Compact Muon
Solenoid (CMS) Experiment have been produced and the
individual boards and crates
validated. The RCT hardware consists of 18 9Ux680mm
double-sided crates containing
custom boards with custom ASICs and backplane. Including
spares, almost 1800 boards
of 6 different types have been produced. Included are a
backplane, Clock and Control
Card (CCC), Receiver Mezzanine Card (RMC), Receiver Card
(RC), Electron
Identification Card (EIC), and Jet/Summary Card (JSC). This
system will receive 8
bit transverse energies (ET) and a characterization bit from
over 8000 hadronic and
electromagnetic calorimeter towers via 4 GBaud copper links
and sum these ET's over
4x4 tower regions for jet-finding, missing ET, and total ET.
Additionally, the
individual tower energies and characterization bit are used
to find electron
candidates. These quantities are then forwarded to the
Global Calorimeter Trigger
(GCT) for further processing and sorting.

After the production and validation of the system, and
before integration with the
other trigger sub-systems, two special test boards were
developed to verify the input
and output of the RCT. The Serial Test Card mimics the input
from the calorimeter
Trigger Primitive Generators (TPGs). This card was used to
validate the links and to
check all routes on the board that could not be validated
without active links. The
Jet Capture Card (JCC) was developed to capture the output
of the JSC and if needed,
generate an external trigger. Using the ability of the RCT to
repeatedly cycle
through its LookUp Tables (LUTs), it was possible to validate
the data paths with
changing patterns for an extended period of time.

Before the JCC long-term tests were performed, small-scale
integration had already
begun. The HCAL and ECAL TPGs were each integrated
separately, providing input data
to the RCT. Data was received successfully at the RCT from
the TPGs on up to 24
links simultaneously. The RCT JCC was used to verify that
the data was aligned in
time. Additionally, the RCT LUTs were used to send data
patterns from a single crate
to the GCT for verification.

Currently, integration tests are performed in a purpose-built
aboveground facility,
with a row of racks identical to what exists underground at
CMS. At this facility
integration of multiple trigger sub-systems can be performed
at once. The ECAL and
HCAL TPG’s have now sent data simultaneously to the RCT.
This was performed with a
real CMS clocking system. In this facility the RCT sent
pattern data from two crates
to the GCT. After the GCT in the trigger chain is the Global
Trigger (GT), where data
was seen using the JCC trigger output, using patterns
generated by the RCT.

Tests to be reported on include long term tests using
patterns with the HCAL and ECAL
TPGs, integrating with the HCAL TPG’s in the Magnet Test
and Cosmic Challenge, and
using real cosmic ray data from the detectors. The RCT will
also send activity
triggers from the JCC to the GT.

Details of past and forthcoming tests and their results will
be described. In
addition, the installation and integration for CMS trigger will
have begun
underground, and this will be covered as well.

Primary author

Pamela Klabbers (University of Wisconsin)


Joseph Lackey (University of Wisconsin) Mathew Jaworski (University of Wisconsin) Monika Grothe (University of Wisconsin) Phillip Robl (University of Wisconsin) Sridhara Dasu (University of Wisconsin) Thomas Gorski (University of Wisconsin) Wesley Smith (University of Wisconsin)

Presentation materials