Department of Electronics - IPN - IN2P3

General & technical Departments
The electtrroni
ics off ALIICE dimuon ttrracki ing chamberrs
IPNO Participation : V. Chambert, P. Courtat, S. Drouet, B.-Y. Ky, J-M. Martin, C. Oziol
Collaboration : Institut de Physique Nucléaire d’Orsay, Saha Institute of Nuclear Physics, Istituto
Nazionale di Fisica Nucleare Sezione di Cagliari, Subatech Nantes
L’électronique des chambres à fils du bras Dimuon d’Alice
Le bras Dimuon de l’expérience Alice du Cern comprend entre autres un système de reconstruction de traces des
particules composé de 10 chambres à fils reparties dans 5 stations. L’IPNO a en charge la coordination de
l’électronique pour tout le bras Dimuon, ainsi que la construction de la station 1. Le système de lecture des
chambres comprend des cartes frontales de lecture et de numérisation des données, des bus de transmission vers
les châssis CROCUS de lecture et un châssis de transmission et de mise en forme du trigger. Après une brève
présentation de ces systèmes nous décrirons de façon plus détaillée le système CROCUS.
Electronics architecture
The ALICE dimuon arm is, for the main parts, composed of
several absorbers, of a trigger system, of a dipole and of a
tracking system. The tracking system is composed of five
stations with two chambers for each of them.
IPN Orsay is in charge of the electronics coordination for
the tracking system (fig 1). It means that front-end
electronics (≈20 000 Manu boards, more than 10 6 channels),
CROCUS read out crates (≈ 22 crates), trigger dispatching
crates (2 crates) and the related software were designed at
Orsay and we will produced for the whole Dimuon
collaboration.
Besides these elements, data bus transmission (bus patch)
were designed at Orsay but each station adapted the system
for its needs and produced them.
Orsay is also responsible for the design and production of
transmission boards called translators and bridges both for
station 1 and 2.
CROCUS crate
A rough estimation of the typical information
number to read in the case of a “mean” collision gives
about 150 kB distributed in the five stations. Using a safety
factor of 2, the electronics will have to handle an
acquisition rate of 1200 evts/s for the lead beams and of
DETECTOR
FEE
FEE
2 x 32
PADs
PATCH BUS
Up to 26 or 3 x 17
MANU BOARD.
Up to 100 PATCH BUS
per detector.
HIGH VOLTAGE
MANU
SLOW CONTROL
DETECTOR: Chapter 1
FEE: Chapter 2
MANU: Chapter 2.1
READ OUT: Chapter 3
DISPATCHING: Chapter 3.2
CROCUS: Chapter 3.3
SOFTWARE: Chapter 3.4
LOW VOLTAGE: Chapter 4
HIGH VOLTAGE: Chapter 5
SLOW CONTROL: Chapter 6
EMC: Chapter 7
ALICE TRACKING DIMUON SYSTEM:
ELECTRONICS & SOFTWARE
Translator
Board.
LOW VOLTAGE
EMC
10 Meter max
Ribbon cable
READ OUT.
CROCUS Crate
Up to 50 PATCH BUS connected.
FRT
DAQ
Optical link:
DDL
100 meter.
PC
CRT
SOFTWARE
Ribbon cable
40 meter
TCI
One crate for all
CROCUS.
FFT FTD
Link to download:
Pedestals.
DSP code.
From CTP
Trigger information:
L0, L1…..
ETHERNET:
- Monitoring.
- Stand alone DAQ.
- Test configuration.
fig 1:
2000 evts/s for the high intensity Ca beams.
- 142 -
The choice has been done to use DSP AD21160M (Digital
Signal Processor) farms to achieve the data readout coming
from the FEE. These DSPs are gathered in « clusters » in 20
specific crates called CROCUS (Cluster Read Out
Concentrator Unit System). Each crate is composed of 5
cards called « frontal » directly connected to the Patch
buses by ribbon cables and of a concentrator card which
collects the data coming from all the frontal cards then,
after, formatting, transmits them to the SIU (Source
Interface Unit) which will achieve the transmission towards
the DDL (Detector Data Link) (fig 1). This modularity
provides a high readout speed and minimizes the