1. 2009-05-15IEEE Real Time 091 Data Acquisition System for Multi-channel Gas Detector Hongyu ZHANG, Kejun ZHU, Haitao ZHU Institute of High Energy Physics, Chinese Academy of Sciences IEEE NPSS Real Time Conference 2009 May 10-15, 2009, IHEP, Beijing

2. Outline System Components Software design and Implementation Software Implementation – PowerPC Software Implementation – PC System Work Modes Calibration mode Electronics Test Charge/Time Channel Calibration Online Data Taking Mode Integration Mode Waveform Sampling Mode Summary 2009-05-15IEEE Real Time 092

3. 2009-05-15IEEE Real Time 093 System Components Two separate systems GEM-TPC RPC/MRPC Each system consists of : Detector system Pipelined front-end electronics system PC 100M Ethernet Switch

4. 2009-05-15IEEE Real Time 094 GEM-TPC GEM-TPC Electronics GEM-TPC - GEM detector for time projection chamber (TPC) study, 312 channels

5. 2009-05-15IEEE Real Time 095 RPC/MRPC RPC/MRPC Electronics RPC / MRPC - for cosmic-ray coincidence measurement, 312 channels, up to 504 channels.

6. 2009-05-15IEEE Real Time 096 Cosmic-ray Experiments

7. System Components - Electronics System Each system has a 9U VME crate System Controller: MVME5100 (PowerPC) Based on 9U VME64x specifications, several kinds of VME modules developed : MCLF - Calibration, logical control and fan-out MROC – Readout control MQT – Charge & Time measurement module, each has 32 Flash ADC ch. & 32 TDC ch. MF-II – Fan-out modules Pre-amplifier boards and cables 2009-05-15IEEE Real Time 097 Electronics Block Diagram

8. 2009-05-15IEEE Real Time 098 Software Implementation PowerPC VxWorks Hardware Configuration CBLT Read Raw Data Checking Event Assembly &Buffering Network Transmission PC Windows XP Run control Electronics Test Q/T Channel Calibration Online Data Taking Online Status Display Online Histogram Display Data Storage TCP/IP Sockets Commands Configure Information Event Data Status

9. 2009-05-15IEEE Real Time 099 Software Implementation – PowerPC OS: VxWorks 5.4 IDE: Tornado 2.0 Statecharts are used in the software design of PowerPC, it is a powerful tool to model the system behaviors. Host computer (PC) sends a series of pre-defined commands to PowerPC PowerPC then does proper state transformation and completes corresponding tasks. Pre-defined commands: LOAD CONF PREP SATR SPTR STOP UNCF UNLD EXIT States: Waiting Initialized Loaded Configured Ready Running PostRunning …

10. 2009-05-15IEEE Real Time 0910 Software Implementation – PC Visual C++ Used to create DLLs (Dynamic Linked Library) Establish TCP/IP sockets  Command socket, Data transfer socket & Status report socket Send configure information and commands to PowerPC Receive, parse and store event data LabVIEW Used to develop GUI, display results and call DLLs

11. 2009-05-15IEEE Real Time 0911 System Work Modes Calibration Mode Electronics test Q/T channel calibration Online Data Taking Mode Integration mode Waveform sampling mode

12. Calibration Mode - Electronics Test Test functions of each hardware modules Measure performances of electronics system Help to find hardware failure Test items Waveform reconstruction Q resolution Q INL/DNL Q crosstalk T resolution T INL T noise level Q/T long-term stability 2009-05-15IEEE Real Time 0912

13. 2009-05-15IEEE Real Time 0913 Calibration Mode - Electronics Test

14. 2009-05-15IEEE Real Time 0914 Abnormal channel, need repair

15. 2009-05-15IEEE Real Time 0915 Calibration Mode - Charge/Time Channel Calibration Least squares linear fit Calibration parameters ( slope, intercept and RMS) of Q and T channels are stored in files for further reference when doing offline data analysis. Help to find failure of electronics channels.

16. 2009-05-15IEEE Real Time 09 Online Data Taking Mode - System configuration and control GUI Fully configurable Configuration Info: PowerPC & PC IP addresses Hardware configure parameters Hardware Module position Freely choose from 3 run modes: Start-pause-stop Run for a given time (in minutes) Run for a given event number

17. Online Data Taking - Integration Mode Online display:  Q/T amplitude spectrums  Q/T channel-hitting spectrums Monitor data taking status Help to choose suitable electronics Q/T channel threshold values  Low threshold helps to observe small signal but may bring too many noise signals 2009-05-15IEEE Real Time 0917

18. Electronics channels to Pad array conversion Use LabVIEW Intensity Graph to dynamically display particle tracks. Gray-scale value of the pad stands for Q/T amplitude of that electronics channel Display refresh time can be changed at any time. 2009-05-15IEEE Real Time 0918 Online Data Taking - Integration Mode Track Display (Q, T, Q&T)

19. Online Data Taking - Integration Mode To achieve high event rate, the following aspects are important: PowerPC side  Interrupt, task priorities  Use 64-bit CBLT (Chained BLock Transfer) to read data from each MQT to PowerPC via VME backplane PC side  Multi-threading: Data acquisition and graphic display (e.g. histogram presenting and track display) must be separated into different threads. Otherwise, the display may slow down the DAQ.  Global variable pool is used to share data for different threads in LabVIEW programming 2009-05-15IEEE Real Time 0919

20. 2009-05-15IEEE Real Time 0920 Online Data Taking - Waveform Sampling Mode When taking data in this mode, signal waveforms of 32 Q channels of the selected MQT module will be displayed dynamically. Waveform data of all channels are stored into files for offline analysis.

21. Online Data Taking - Waveform Sampling Mode 2009-05-15IEEE Real Time 0921 Help to intuitively observe signals (amplitude, width, arrival time, etc) in the detector/electronics nearby channels. It’s a very useful method to observe the signals and the status of detector and electronics channels, such as baseline and noise level.

22. Online Data Taking - Waveform Sampling Mode 2009-05-15IEEE Real Time 0922 In the beginning, waveform sampling mode was just an auxiliary method to test if the whole system (detector and electronics) is ready to work. It was designed to read out sampling values one by one from each registers, therefore it is pretty slow and can only observe cosmic ray events. Now the detector designers realize that waveform sampling mode helps a lot in detector performance study, they need to take much more waveform data to do analysis. In the upcoming version of DAQ software, online waveform data will be read out from MQT modules by using CBLT, which will be much more efficient than before.

23. Summary The DAQ software worked well in cosmic-ray experiments at lab, as well as in test beam experiments at IHEP and KEK. The system has been proved to be stable and reliable, meet the design requirements for the system. 2009-05-15IEEE Real Time 0923

24. Thank you! 2009-05-15IEEE Real Time 0924