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| − | == Tagger Hodoscope ==
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| − | The tagger hodoscope consists of 218 scintillator counters which are
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| − | installed behind the focal plane of the tagger magnet. The light produced in
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| − | each counter is detected using Hamamatsu R9800 PMTs which are instrumented
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| − | with JLab's custom designed dividers and divider-based amplifiers. The PMTs
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| − | are operated at around 950 V. The hodoscope will
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| − | be used for tuning the orientation of the radiator crystal
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| − | by measuring the photon beam energy spectrum. This procedure
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| − | will require involvement of experts and will not be performed by
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| − | shift crew members. During data taking, the hodoscope will
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| − | be used to monitor the beam stability.
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| − |
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| − | == Routine operation==
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| − |
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| − | The shift crew will be monitoring the detector performance parameters such as the counter rate per channel and detector occupancies and also check PMT high-voltages.
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| − | Any hot or dead channels have to be recorded in the log file. If the average counter rate significantly deviates (the range will be specified for each shift) from
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| − | the expected rate, the run coordinator should be called. In the case an alarm system detects the PMT current trip, the PMT high-voltage will be shutoff. The crew should
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| − | set the voltage on the PMT using the GUI interface (see instructions below). If the problem persists the expert should be called.
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| − |
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| − | 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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| − | bring up the GUI screens can be found in [[Slow Controls Shift| Section Slow Controls]].
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| − |
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| − | == Voltage Settings and Control ==
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| − | All PMT voltages and trip currents will be preset by the detector experts. The HV will be switched on by the shift crew by clicking on 'All HV' button
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| − | on the GUI interface. If any of the bases fail to set their high voltage a non-expert will first retry clicking 'All HV'.
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| − | If the problem persists the expert should be called.
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| − |
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| − |
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| − | == Interlocks ==
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| − |
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| − | == Expert personnel ==
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| − | The individuals responsible for checking that the Hodoscope is ready to take data and setting its operating parameters are shown in following table.
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| − | Problems with normal operation of the hodoscope should be referred to those individuals and any changes to their settings must be
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| − | approved by them. Additional experts may be trained by the system owner and their name and signature added to the document residing in the Hall D Counting House.
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| − |
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| − | {| border=1
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| − | |+ Table: Expert personnel for the Hodoscope system
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| − | |- bgcolor=#DFDFDF
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| − | ! width=200px | Name !! width=100px | Number !! Date of qualification
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| − | |-
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| − | | Alexander Somov || align=center | (757) 269-5553 || align=center |
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| − | |-
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| − | | Franz Klein || align=center | || align=center |
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| − | |}
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| − |
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| − | == Tagger Microscope ==
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| − |
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| − | The tagger hodoscope consists of an array of 100 x 5 scintillators which are installed on the tagger magnet focal plane and
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| − | will be used to monitor the photon beam energy spectrum in the 'coherent peak' region.
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| − |
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| − | == Routine operation==
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| − |
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| − | The shift crew will be monitoring the detector performance parameters such as the counter rate per channel and detector occupancies
| |
| − |
| |
| − | 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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| − | bring up the GUI screens can be found in [[Slow Controls Shift| Section Slow Controls]].
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| − |
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| − | == Voltage Settings and Control ==
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| − |
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| − |
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| − |
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| − | == Expert personnel ==
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| − | The individuals responsible for checking that the Hodoscope is ready to take data and setting its operating parameters are shown in following table.
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| − | Problems with normal operation of the hodoscope should be referred to those individuals and any changes to their settings must be
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| − | approved by them. Additional experts may be trained by the system owner and their name and signature added to the document residing in the Hall D Counting House.
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| − |
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| − | {| border=1
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| − | |+ Table: Expert personnel for the Hodoscope system
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| − | |- bgcolor=#DFDFDF
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| − | ! width=200px | Name !! width=100px | Number !! Date of qualification
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| − | |-
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| − | | Alexander Somov || align=center | (757) 269-5553 || align=center |
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| − | |-
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| − | | Richard Jones || align=center | || align=center |
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| − | |}
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