1. The IFR Online Detector Control at the BaBar experiment at SLAC
Pierluigi Paolucci
Stanford Linear Accelerator Center and I.N.F.N. of Naples
21 November 2018
Pigi Paolucci

2. Summary Introduction; Software: IFR description; System Overview;
Hardware:
System Overview;
Single Rate;
Analog readout;
Wiener Crate.
Software:
System Overview;
EPICS;
State Machine;
Component Proxy;
Data Analysis;
Conclusions.
21 November 2018
Pigi Paolucci

3. Introduction I
BaBar is a B-factory experiment on the PEP II accelerator at the Stanford Linear Accelerator Center;
The goal of this detector is to search for and study possible CP violation in the decay of the B meson;
Such studies will require both high statistics and good control of systematics
Stable and continuos operation under well-controlled conditions
Online Detector Control plays an important role.
21 November 2018
Pigi Paolucci

4. Introduction II BaBar consists of 5 sub-detectors:
Silicon Vertex Tracker;
Drift Chamber;
Detector of Internally Reflected Cherenkov ;
ElectroMagnetic Calorimeter;
Instrumented Flux Return.
m detection and neutral hadron identification
21 November 2018
Pigi Paolucci

5. Introduction III The Instrumented Flux Return consists of:
342 RPC chambers in the Barrel region;
432 RPC chambers in the Endcap region;
80 High voltage channels;
about 3000 front-end electronic cards;
48 low voltage power supplies;
8 DAQ crates;
21 November 2018
Pigi Paolucci

6. ODC hardware schema RPC: Single Rate, Dark Current and Gas system.
Front-end: Low Voltage and Single Rate.
Detector: Trigger, Temperature and DAQ crate.
ODC hardware schema
21 November 2018
Pigi Paolucci

7. IFR Online Detector Control Overview
Control and Monitor: hardware software
High Voltage
Low Voltage
DAQ crate
Monitor:
Single Counting Rate
Dark Current
“Iron” Temperature
Gas system;
Trigger
TOTAL
21 November 2018
Pigi Paolucci

8. Detector Control DAQ system I
Master VME crate placed in the electronic room with:
CPU MVME 177;
HV controller;
2 “CAN-bus” boards;
6 VME Scalers;
3 Gate Generators;
5 Interlock boards.
21 November 2018
Pigi Paolucci

9. Detector Control DAQ system II
8 Slave custom crate placed on the detector
8 digital multiplxers:
32 ECL input channels;
Reset and Clock (NIM);
2 ECL/NIM output signals;
8 analog boards(CAN-bus);
1 controller:
opto-coupled DMUX input and output signals.
21 November 2018
Pigi Paolucci

10. Single Counting Rate
The 1608 fast-OR signals, generated by the front-end cards connected to the longitudinal strips, are used to monitor the Single Counting Rate of each RPC chamber.
A digital multiplexer with 32 ECL input channels is used in order to reduce the number of channels to acquire.
Using 8 Slave Crates DMUXs channels the whole RPC system is monitored with 4 scaler boards.
21 November 2018
Pigi Paolucci

11. More hardware subsystems
The Slave crate contains also 8 General Monitor Boards used in BaBar to monitor analog information:
RPC dark current, low voltage and temperature
The HV system consists of 5 CAEN SY127 mainframes.
Each HV channel is split in 36 using an HV box placed on the detector. This box provides also 36 analog signals proportional to the RPC dark current.
21 November 2018
Pigi Paolucci

12. Slave Crate HV system Detector Electronic house Fast-OR signals
Analog signals
CaenNET
CAN-bus
Electronic house
21 November 2018
Pigi Paolucci

13. 21 November 2018
Pigi Paolucci

14. Software Overview (EPICS)
The BaBar/IFR Online Detector Control use VxWorks and EPICS to implement slow control data flow and to develop part of the readout module.
21 November 2018
Pigi Paolucci

15. EPICS structure
IFR software package has been developed starting from the EPICS database:
2600 hardware records +
1400 software records used to summarize the results and the status of each IFR subsystem/sector.
Each record contains information as:
scan period, alarm limit, alarm severity Hardware
units, precision, conversion, link Software
alarm/database/monitor dead-bands EPICS tools
All the EPICS tools have access to the records.
21 November 2018
Pigi Paolucci

16. Software Overview (EPICS)
Some EPICS tools are used in the BaBar experiment as the Alarm Handler.
It display the Alarm Status of all the EPICS records, organized in “logical” threes.
21 November 2018
Pigi Paolucci

17. Component Proxy Is a special software layer above EPICS structure;
It fill the gap between EPICS and the BaBar Online;
It also bridges the semantic gap between the C-language EPICS part and the Object-Oriented-C++ parts (Run Control, Archiving and Analysis.
21 November 2018
Pigi Paolucci

18. EPICS is interfaced with the BaBar Run Control through the Component Proxy and with the BaBar Database through the Archiver and KeyLookup processes.
Java is used to analyze the data retrieved from the db and to produce a set of histograms used during the data tacking.
21 November 2018
Pigi Paolucci

19. BaBar Alarm Structure Each EPICS channel has 2 alarm limits:
The first one is just a warning (color code is yellow);
The second one is a real alarm (color code is red).
The alarms are sent from the EPICS database to the EPICS Screen, Alarm Handler, Java Browser and Database.
21 November 2018
Pigi Paolucci

20. Single Rate Monitor EPICS Proxy database ntupla 21 November 2018
Pigi Paolucci

21. IFR State Machine
BaBar has 3 different operating States, runnable, injectable and calibration corresponding at different hardware/software configuration of each subsystem.
An EPICS State Machine (sequencer) receives the State key from the Run Control and set the IFR configuration (HV, LV and DAQ).
It can work in Local mode (from the IFR console) or in Global mode (from the PEPII or BaBar console).
It calculates also the status of each IFR hardware subsystems.
21 November 2018
Pigi Paolucci

22. IFR Console
21 November 2018
Pigi Paolucci

23. Wiener Crate Monitor
21 November 2018
Pigi Paolucci

24. HV Console
21 November 2018
Pigi Paolucci

25. Conclusions The IFR Detector Control is working since January 1999.
The data collected up to now have been used to study the performances of the detector during the Cosmic Run and to monitor it during the Data tacking.
All the ODC information are stored into the BaBar database permitting to use the detector conditions in the offline analysis.
EPICS proved to be a very powerful, reliable and friendly system to control and monitor both BaBar and PEP II.
21 November 2018
Pigi Paolucci