Atender procesos de auditorias, de acuerdo a las alarmas generadas por el Sistema, que

The design of the ProtoDUNE-SP safety and control system is largely based on the experience gained in collaboration with ETH Zurich during the pilot WA105 project at CERN. The compo- nents of this system and their functions are as follows:

• The Process Control System (PCS) reads temperature sensors including the Vertical T Gra-

dient monitors, the pressure sensors in the gas ullage, the liquid argon level meter, the purity monitors inside the cryostat, and the trace analyzers (O2, N2, H2O) in the external recirculation line.

• The Detector Control System (DCS) monitors and controls the low-voltage (LV) and high-

voltage (HV) from the power supplies.

• The Detector Safety System (DSS) performs temperature surveys and monitors interlocks

and alarms.

The supervisory software is based on the JCOP framework, an integrated set of software tools originally developed for the control of the LHC experiments and now used in several more ex- periments at CERN. The framework provides a graphical user interface to visualize the trends of monitored values and alarm/interlock conditions. These values and alarms are automatically stored in a dedicated database for offline use. Remote monitoring is possible via a web interface. The responsibility for the system is split between ProtoDUNE-SP and CERN:

• The ProtoDUNE-SP experiment is responsible for all sensors, power distribution, etc., inside

the cryostat, as well as for defining the system specifications, I/O parameters and control, and safety logic.

• CERN EP/DT-DI is responsible for developing and testing the supervisory control of the

system and data acquisition (SCADA). This includes connecting the control system to the cryogenics instrumentation inside the cryostat and to all the systems that require monitoring

and/or control, such as power supplies, cameras and lighting.

In particular, CERN EP/DT-DI is developing a dedicated readout system based on National Instrument modules to allow the multiplexing of the RTDs inside the cryostat. A prototype of this readout system is currently under test.

Figure 2.71 shows the general architecture of the control and safety system for ProtoDUNE-SP, including the PCS, the DCS and the DSS.

The control system is composed of:

• a chassis for electrical distribution (380 Vac, 220 Vac, 24 Vdc redundant);

• two chassis for the PCS, composed of an FPGA, signal conditioners, interface, and cabling; • one chassis for the DCS, composed of an interface for LV/HV monitoring & control;

• a chassis for the DSS, composed of an FPGA and relays for the safety of the experiment; • a chassis for a PC data acquisition & supervision (PVSS SCADA Supervisor), composed of

a computer with a display monitor, a switch and a server;

• four chassis for the remote I/O to capture signals close to the detector and to avoid multi-

cabling structure; and

• one chassis for the HV, controlled by the slow-control system.

Chapter 2: Detector components 2–116

Chapter 3

Space and infrastructure

ProtoDUNE-SP is to be housed in an extension to the EHN1 hall in the North Area of the Prévessin site at CERN. The cryostat is constructed in a pit inside the building, surrounded on three sides by the pit walls. On the fourth side of the cryostat, an ISO 8 clean room provides a space to construct, test and assemble the TPC and other components. A material pass-through structure called a sas 1 is adjacent to the clean room. Figure 3.1 shows the layout of these structures in

EHN1. A naming convention has been established for the four sides of the cryostat, shown in Figure 3.2. The upper side is Jura, the lower isSalève, the left isBeam, and right isDownstream.

Figure 3.1: Layout of ProtoDUNE-SP cryostat, clean room and material sas in EHN1

Figure 3.3 shows an elevation section view of the cryostat indicating the position of the TCO and the location of the integrated cold testing stand (described in Section 4.4).

Inside the clean room, a series of rails facilitate the movement of the detector components during the test and installation processes. The conceptual layout of these rails is shown in Figure 3.4. 1_{Sas is a French word for a space outfitted with two doors, where one can only be opened if the other is closed; a sas}

Chapter 3: Space and infrastructure 3–118

Figure 3.2: Conventions for labeling the four sides of the cryostat

The rails are positioned vertically at the same height as the detector support structure (DSS) rails inside the cryostat. A temporary rail is installed through the TCO to bridge the DSS rails and clean room rails. All the large components of the cryogenics piping and TPC are supported from these rails on movable trolleys as they are transported to the interior of the cryostat. Figure 3.4 also shows the approximate dimensions for the sas and the footprint of the clean room space. These spaces are limited by the pit walls on two sides, and by the supports for the beam and beam instrumentation on the other.

Figure 3.4: Conceptual layout of rails in clean room to facilitate movement of TPC components; approximate dimensions for the material sas and the footprint of the clean room space are shown. (The supports for the beam and the beam instrumentation are not shown.)

The lighting inside the clean room and any temporary lighting inside the cryostat is filtered to limit the exposure of the PDS components to UV light; wavelengths below 450 nm are filtered out.

Chapter 4: Detector Installation 4–120

Chapter 4

Detector Installation