1. Speaker: Kurenya A.N. Head: Petkov V.B. BNO INR RAS
The hardware and software implementation of the data aсquisition systems for air shower facilities “Andyrchy” and “Carpet-3”.
Speaker: Kurenya A.N.
Head: Petkov V.B.
BNO INR RAS

2. Objectives of work.
Development and creation of a registration system based on the VME bus, TDC and QDC cards from CAEN ( and electronics based on FPGA (programmable logic integrated circuits), for the Andyrchi and Carpet-3 units.
Creation of a real-time system for determining astronomical coordinates and transferring them to the INASAN observatory at Terskol Peak.

3. Block diagram of the registration system for air shower facilities “Carpet-3”.

4. The main components of the registration system :
TDC V1190B (CAEN); 64 channels, minimum time resolution between triggers 5 ns, LSB 100/200/800 ns, dynamic range up to 104 μs.
QDC V792 (CAEN); 32 channels, 12 bits, input range up to 400 pC.
The block for generating a trigger based on FPGA Developer: Dzaparova I.М.
The receiver of clock signals of exact time on the basis of FPGA for ISA bus. Developer: Yanin V.F.
PCI-VME controller A2818/V2718 (CAEN); 32-bit, 33 MHz.
Industrial computer.

5. Trigger blocks of the "Carpet" facilities.
The "Carpet" facilities consists of 400 liquid scintillation detectors, which cover a square with an area of ​​200 m2 and grouped in 25 (5x5) modules with 16 (4x4) detectors in each. Six remote points intended to determine the direction of arrival of the EAS are located at distances of 30 and 40 meters from the center of the "Carpet". The area of ​​each remote point is 9 m2. Trigger for TDC is generated when any not nearby four Carpet modules operate and any remote point is triggered. Signals to the trigger block come from the anodes of the photomultiplier through active adders and compensated drivers . This trigger is also fed to the clock receiver's clock board to record the event time.

6. Trigger for QDC on any signal of any module or remote point of facilities "Carpet". The absence of overlap is guaranteed by the dead time QDC of the order of ten microseconds during which the measurement is made. The signals going to the QDC are delayed by 20 ns in order to get to the trigger measurement window. The measuring window of the trigger is set by its length and is 800 ns.

7. Comparison of the results of the old and new data collection system on the "Carpet" facilities.
The VME-based system registers more events. As at the expense of greater speed and better resolution, and because of another trigger.

8. The quality of the information for the calculated angle Θ is the same.

9. The quality of information for the calculated angle Φ in the VME is better, since the peaks correspond to the angles of the location of the remote modules.

10. Block diagram of the registration system for air shower facilities “Andyrchy”.

11. The main components of the registration system:
TDC V1190B (CAEN); 64 channels, minimum time resolution between triggers 5 ns, LSB 100/200/800 ns, dynamic range up to 104 μs.
QDC V792 (CAEN); 32 channels, 12 bits, input range up to 400 pC.
QDC V965A (CAEN); 8 channels, 12 bits, input range up to 400 pC.
The pulse counter UNIO48-5 (FASTWELL) based on FPGA and two modules of optical isolation TBI-24 / 0C-3; 48 channels, 16 bits, frequency up to 10 MHz.
The block for generating a trigger based on FPGA Developer: Dzaparova I.М.
The receiver of clock signals of exact time on the basis of FPGA for ISA bus. Developer: Yanin V.F.
PCI-VME controller A2818 / V2718 (CAEN); 32-bit, 33 MHz.
Two industrial computers.

12. Trigger blocks of the "Andyrchy" facilities.
The "Andyrchi" installation consists of 37 standard detectors based on a plastic scintillator of 1 m2 each. The installation covers an area of 4.5*104 m2 in 40 m increments.
Trigger for TDC is generated when at least four detectors operate within ~1.6-mikrosecond time window. The signal is transmitted to the output of the trigger block with a delay of 14 μs to ensure the reception of the entire dynamic range of the logarithmic converters of the detector systems. The trigger is fed to the clock receiver board for the exact time clock to record the event time.
The trigger for QDC is produced in the same way as in the "Carpet" facility, from any triggered detector. The signal duration is ~3.2 μs. After the trigger is generated, the circuit is blocked for 600 ns.
The trigger for reading data from the UNIO48-5 meter board is the interrupt signal of the exact clock receiver board. The clock receiver is set to give an interrupt every millisecond.

13. Software.
The data collection systems of the «Andyrchi» and «Carpet» facilities are similar, therefore they have similar software. The basis for the data acquisition programs is the real-time driver for the exact clock receiver board. The signal of the exact local time is fed from the BUST facilities (Big Underground Scintillation Telescope), where the global time is recorded by the GPS signal, which allows calculating the world time of the recorded event, knowing the course of the local clock relative to the world time.
The software is written for the Linux operating system (CentOS 6.x).
The real time driver for the clock board is a symbolic logical device that allows the user to read the «/dev/ISA_TIME» path string for users with high privileges and «/proc/ISA_TIME» for users with normal privileges.
The data line contains the day number from the beginning of the year, hour, the number of the fifteen minute wound from the beginning of the day, minutes, seconds and milliseconds.
In the "Andyrchi" computer with UNIO48-5 boards, the interrupt handler in the driver reads and provides the counters data.

14. The online data collection programs of the facilitys have a multithreaded architecture: the main thread that performs hardware initialization and application management functions, the data collection thread from the TDC, the data collection thread from the QDC, and the planned but not yet implemented data processing thread. Multithreading of programs is implemented using the library "Boost 1.41" from the standard repository CentOS 6.x. Data is written into files for fifteen minutes. Each file contains a header with the creation time to the wound number, and each event header with a time to millisecond.
Data processing is still carried out offline on a separate computer by several programs, each of which performs its function: calculation of the angles of the constituting EAS vector in the local coordinates of the facilities, recalculation to astronomical coordinates, search of event clusters. The results of these programs are recorded on a dedicated server.

15. Transfer of data to the observatory at the peak of Terskol.
Access to the processed data is carried out by two communication channels:
1. a local computer network formed by three «Cisco Aironet 1410» modules, one of which works at the Cheget peak in the access point mode, and the other two in the eth-wifi bridge mode at the «Andyrchi» facility and at the Terskol peak.

16. At the same time wi-fi communication is carried out for a distance of about 20 km.
2. Routing via the internet with a fixed IP address.
Both channels allow you to connect to the dedicated server via HTTP and FTP, and over the local network using the SMB protocol. Using the processed data of the BNO facilities, scientists at the Terskol Peak Observatory can search for anomalous objects in the optical range for their further identification and observation.