Difference between revisions of "Forward Drift Chamber Shift"
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== Routine operation== | == Routine operation== | ||
| − | The most important task for the shift workers is to monitor the parameters (using GUIs) of the following FDC related subsystems: High Voltage, Low Voltage (including thresholds), Gas system, and the Cooling system. A description of how to bring up the corresponding GUI screens and how to operate them can be found in [[Slow Controls Shift| Section Slow Controls]]. The HV and LV subsystems, as well as and the Gas and Cooling systems have common GUIs. The GUIs are designed to show green color if all the parameters | + | The most important task for the shift workers is to monitor the parameters (using GUIs) of the following FDC related subsystems: High Voltage, Low Voltage (including thresholds), Gas system, and the Cooling system. A description of how to bring up the corresponding GUI screens and how to operate them can be found in [[Slow Controls Shift| Section Slow Controls]]. The HV and LV subsystems, as well as and the Gas and Cooling systems have common GUIs. The GUIs are designed to show green color if all the parameters in a certain subsystem/subgroup are within the limits. If any of the parameters is out of limits the background for the corresponding subsystem/subgroup will turn red. Examples of the GUIs are shown below: |
| − | + | [[Image:BCAL_environmental_sensors.png | thumb | 400px | Fig. 1. Environmental sensors for the BCAL. The red ovals highlight the information provided to the user, available for the upstream and downstream ends independently. | |
| + | This includes the forty-eight temperature readings of each RTD on the cooling plates, which are in thermal contact with the back of the MPPC sensors, the nitrogen flow, and the four | ||
| + | measurements of temperature, humidity and dew point of the gaseous atmosphere of the readout electronics.]] | ||
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| + | <font color=red> Operations beyond what was specified above shall only be performed by the system expert or under his/her direction </font>. | ||
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During routine operation the user will need to monitor the environmental conditions, which may affect BCAL performance, as well as turn the | During routine operation the user will need to monitor the environmental conditions, which may affect BCAL performance, as well as turn the | ||
| − | system on and off. The following instructions are for non-experts during routine operation.<font color=red> | + | system on and off. The following instructions are for non-experts during routine operation.<font color=red> </font> If the expert directs an operation outside the ones described here, a specific note must be entered into the log book. |
Control and monitoring of the system is accomplished using the Hall D graphical user interfaces (GUI) to EPICS [http://www.epics.org] [http://www.aps.anl.gov/epics]. A description of how to | Control and monitoring of the system is accomplished using the Hall D graphical user interfaces (GUI) to EPICS [http://www.epics.org] [http://www.aps.anl.gov/epics]. A description of how to | ||
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===Checking the environment=== | ===Checking the environment=== | ||
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The temperature and humidity measurements of the BCAL can be displayed using the GUI shown in Fig. 1 . The controls and monitoring of environmental conditions is accomplished separately for the upstream and downstream readouts of the BCAL, which are connected to | The temperature and humidity measurements of the BCAL can be displayed using the GUI shown in Fig. 1 . The controls and monitoring of environmental conditions is accomplished separately for the upstream and downstream readouts of the BCAL, which are connected to | ||
Revision as of 16:47, 2 June 2014
The Forward Drift Chambers
The Forward Drift Chamber (FDC) system consists of four identical packages, each having six chambers (cells). These are planar drift chambers with both wire and cathode strips being readout, in total 12,672 channels.
The cells within a package have independent gas volumes, but are separated with a flexible mylar membrane and therefore the pressure difference between neighboring cells should never exceed 30~Pa and should normally be less than 5~Pa.
Positive (up to 2200V) and negative (up to 500V) HV is applied on the sense and field wires respectively with dark currents not exceeding 3 microA per HV channel .
The detector (including cables) emits a total power of about 1500~Watt, of which about 900~Watt inside the magnet, due to the LV applied on the detector pre-amplifieres. A cooling system using Fluorinert is used to keep the temperature on the pre-amplifiers within the permissible limits. The LV system should never be turned ON if the cooling system doesn't work .
Routine operation
The most important task for the shift workers is to monitor the parameters (using GUIs) of the following FDC related subsystems: High Voltage, Low Voltage (including thresholds), Gas system, and the Cooling system. A description of how to bring up the corresponding GUI screens and how to operate them can be found in Section Slow Controls. The HV and LV subsystems, as well as and the Gas and Cooling systems have common GUIs. The GUIs are designed to show green color if all the parameters in a certain subsystem/subgroup are within the limits. If any of the parameters is out of limits the background for the corresponding subsystem/subgroup will turn red. Examples of the GUIs are shown below:
