Notes for using the
Neutron Wall subsystem for HECTOR experiments
When you start a MIDAS session from the euroball ID you must run the experiment
ancillary. As the session starts look in the Session Log window for the message You are now working with the experiment ancillary. If you see
anything else (such as You are now
working with the experiment EUROBALL)
then
Go to the Euroball
Experiment Control window
Click on More
Actions at the bottom
Select Show
Main Menu from the list
Go to the Euroball
main menu window
Click on Access
Control
Select Experiment
Access from the list
Go to the Accessing
an Experiment window
Click on the button Leave
Select ancillary
from the list
Click on the button Join
Now look for the message You are now working with the experiment
ancillary in the Session Log
window.
This setting can be saved as
the default value.
In the window Euroball Experiment Control check that
the checkbox labelled VME Electronics
is checked. This should be true if you are using the main Euroball system
control workstation (eb63). If the box
is not checked then click on it to enable.
This will enable the actions
associated with the Neutron Wall and other VME electronics when you use the
main GO and STOP buttons.
The HECTOR electronics consists of 2 CAEN VME modules.
ADC CAEN 879 in slot 10
TDC CAEN 878 in slot 8
The positions of these
modules in the VME crate should not
be changed unless the VME Configuration
and LUT files are modified
accordingly. The Module ID in the VME
Configuration MUST be
the slot position of the module (GEO Address) in the VME crate.
Current mapping from ADC/TDC
channels to group/item is
ADC channel 0->9 group 212->221 item 0 Hector
Eslow
ADC channel 10->19 group
212->221 item 1 Hector Efast
ADC channel 20->27 group
160-167 item 0 Helena
ADC channel 31 group
247 item 1 correlation pulser
TDC channel 0->9 group
212->221 item 2 Hector Time
TDC channel 20-27 group
160->167 item 1 Helena Time
TDC channel 31 group
247 item 2 corrleation pulser
The VME electronics is read out using the Neutron Wall interfaces.
This connects via DT32 bus to Event Collector ec1 and Histogrammer hist1.
Data from the HECTOR electronics can be histogrammed
using histogram server hist1.
Start the Histogrammer window and select Histogrammer hist1 (this is important).
Select the Detector type Group.
The group range should be Low
group = 212 and High group = 221
for HECTOR and Low group = 160 and High group = 167 for HELENA.
Select the Qualifier q0
Select Low item = 0 and High item
= 2 for HECTOR and Low item = 0 and High item = 1 for HELENA
Select Channels = 4K
Click on Create to generate 64 histograms.
Histogram name is of the
format Group???.Item?.q0
In order that the VME control works correctly it is
essential that the Euroball session
uses the same VME configuration that was used when the configuration was
downloaded into the VME server (see later).
The configuration loaded into the VME server is written to the file
/MIDAS/experiments/ancillary/[server_name]_current_configuration. For the
experiment ancillary the VME server
for the ancillary electronics is vme.
Hence [server_name] is vme in this case.
The VME Configuration and Control window can be opened by clicking on
the Open button for VME Electronics in the Euroball Experiment Control window.
When the software starts the configuration held in
/MIDAS/experiments/ancillary/vme_current_configuration is loaded automatically.
Only modules mentioned in the configuration will be controlled
by the experiment STOP and GO button.
The VME control window is started by clicking the Open button for VME Electronics in the Euroball
Experiment Control window. This window allows you to edit the VME
electronics configuration. It is strongly
advised that you do not change the VME hardware configuration (and in
particular any module generating VME data) unless you really know what you are
doing.
If you do change the VME
hardware configuration you will need to edit this configuration window. You can
save changes made or restore a previously saved configuration by clicking on the button Save/Restore Configuration.
To load a new VME configuration
(or restore an old one) into the VME server click on the button Load Configuration into Register Server. If you have changed the configuration of
modules which generate VME data then you will also need to recreate the Look Up
Table (LUT) and VME Address Table (VAT) files. You will be prompted to do this
by the Load operation and also by clicking on the button Generate LUT & VAT files.
The HECTOR Configuration has been saved as the file
HECTOR dated Jan30 14:14 (but check for a later version)
The Load Configuration function also performs the SETUP action on all VME modules. This will include setting all
thresholds and discriminators in ADC modules to default values and setting the
VME address information for all data sources. There is a SETUP electronics button in the VME Configuration &
Control window which can be used at any time to perform the SETUP action.
Note – The SETUP action
checks that all modules perform a certain VME cycle correctly. If a module in
your configuration is missing or not operating correctly you will get a warning
message. This is the only time that VME modules are checked for correct
operation.
The VME option in the pull
down menu Parameter Save/Restore in
the Euroball Experiment Control
window or the button Save/Restore Setup
in the VME Configuration & Control
window will start a window (Saving and Restoring VME Module Setups)
which enables all the adjustable parameters for the VME modules in the
configuration to be saved or enables a previously saved set of parameters to be
restored.
The HECTOR Parameter Setup has been saved as the file
HECTOR dated Jan30 16:53 (but check for a
later version)
You can start the control
window for any VME module either from the VME
menu in the Main Menu or by double clicking on the
module in the VME configuration
window.
The button RESET electronics in the VME Configuration & Control window
will set all VME modules into a good state. It does not perform the SETUP
operation. Hence any custom setting of modules is preserved.
The GO button in the Euroball Experiment Control (or the GO
Electronics button in the VME
Configuration & Control window) will set all VME electronics into the
GO state.
The STOP button in the Euroball Experiment Control (or the HALT
Electronics button in the VME
Configuration & Control window) will set all VME electronics into the
STOPPED state.
Neutron Wall
Interface
This is a VME module which you will find in the
Neutron Wall electronics VME crate. It provides the interface between the VME
adc readout system and the DT32 bus and also to the main Trigger system. You
can start the Neutron Wall Interface Setup
window by selecting Neutron Wall
from the VME Module Setup menu in
the Euroball Main Menu. The setup
parameters for the interface can be saved and restored in the same manner as
for all VME modules.
The LUT (Look Up Table) needed to convert the VME data addresses (module GEO address and adc subaddress) to the VXI data addresses (group and item) are loaded automatically by the software in the Neutron Wall VME processor. This uses the LUT file /MIDAS/experiments/ancillary/LUT.vme which is created by the button Generate LUT & VAT files in the VME Configuration & Control window.
Always STOP data acquisition if at all possible.
If this system is restarted for any reason then it is
necessary to reload the VME configuration into the processor. Go to the VME Configuration & Control window
and click the button Load Configuration
into Register Server.
You will be
prompted to do this by the system restart procedure
Then go to the VME
Configuration & Control window and click on RESET electronics and then use Save/Restore
Setup to restore all adjustable parameters and get all your VME hardware
back into a good known state.
For the HECTOR experiments the VME parameter setup is
saved in the file named HECTOR (see
previously)
As long as the VME
Electronics checkbox in the Subsystems
required list is selected in the Euroball
Experiment Control window then any action required on the VME electronics
at GO and STOP is performed automatically.