PREX "How To" Page

last updated: April 16, 2010
Note to expert: After you update the file, make sure to set file group to a-parity and set the permission to group-writable so other experts can update this file ! chgrp a-parity * ; chmod 775 *

HAPPEX/PREX Data Acquisition
HAPPEX/PREX Data Analysis
- Starting Online Data Monitor
- Starting prompt analysis
Spectrometer
Target How to
- The PREX Cryogenically Cooled Lead/Diamond Target
- A general reference for all things target is
Spectrometer Data Acquisition
Spectrometer Data Analysis
- Online (Podd) analysis
Hall A Detectors
Compton Polarimeter
- Compton Polarimeter Home page.
- NEW, Apr 20 Megan's Opmanual.
- Compton Data-Taking instructions. (partly obsolete, see instead Megan's Opmanual.)
- Compton Logbook (analysis results)
Helicity Controls
- Changing the Half-WavePlate
- PITA Scan
- HAPPEX Charge Asymmetry Feedback
Miscellaneous
Other Problems
- If you can't solve a problem

Shift Worker Responsibilities

Shift Leader:

follow the runplan and communicate with RC or experts whenever problems happen that cannot be solved by shift workers.
make sure data taking quality and an efficient use of beam time.
In addition to the items above and obvious stuff as defined in the COO, please log in shift summary:

run list (PREX DAQ runs);
all major events including accesses.

Target Operator:

Watch the target, see Target Info
Since being TO is easy, please help the shift leader and third person.

Third person:

Start and stop the DAQ.
Do online replay of all production runs;
Compare replay histograms with the sample ones and report to shift leader any unexplained differences. Halog them.
The shift leader or TO can help.

HAPPEX/PREX Data Acquisition

HAPPEX DAQ cold start

Note: This is for HAPPEX DAQ. If you want to cold start spectrometer DAQ see Spectrometer DAQ cold start.

To switch DAQs see the checklist to switch DAQs.
Do the following at a shell prompt on adaql5 on the apar account. This does a kcoda, etc, for you:

> startcoda
The Runcontrol GUI will start up. Now click on the Connect button.
Wait 10 seconds, then click on Configure. A dialog box pops up and you must choose the configuration you want, which is presumably Prex.

           List of Useful DAQ Configs 

 All these can be used for the experiment.  Ask the RC which is preferred at the moment.

   PREX -- Full config, all crates.
   PrexNoQweak -- Full config minus the Qweak crate (it's less important and may have crashed)

Wait for configuration to finish (see messages in text box at lower left), then click Download.
Wait for that to finish. Now you can click Start Run to start a run (see section on Running CODA).
In another workspace, open up xterms for monitoring the ROCs by starting the ROC IT GUI:

> roc_it
Click on OPEN ALL. An xterm should open for each IOC. If you are asked for a login name, use adaq as the user. The password is the same as in the counting house computers.

NOTE: After HAPPEX DAQ start, ensure that the dithering and asymmetry charge feedback is turned back on.

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Dithering should be on throughout the PREX running.

To check the current dithering status:

Click on "Dithering" on the Online Data Monitor. If dithering is active, then the characteristic dithering plots should show some wiggles and should be updating every 8 minutes or so.
If you are not sure that dithering is active or if dithering is inactive, then call one of the dithering experts on call: Mindy(315-415-2084), John(978-337-1270), Ahmed(315-436-8047)
NOTE:: greenmonster is in a defunct state right now. So strictly follow the instructions below, and don't trust the greenmonster display on bmw other than those mentioned below. Dont press any buttons on greenmonster other than specified below either.

To TURN ON dithering:

Log in if necessary to any of adaql6-adaql10 machines on the apar account
Bring up a greenmonster terminal by typing
> greenmonster
Click on
> Toggle Kill Switch

Kill Switch is OFF

Go to ROC23 terminal or log onto one as telnet hatsv9 2004. If you cant log on, then it means that there is a terminal open for ROC23 already. Find it.
In the ROC23 terminal type
> initBMW
This will display a bunch of coil information. For coils 1-8, check that the amplitude = 100mA, frequency=15 Hz,and # of periods = 50
If the coil parameters are other than these numbers, then call one of the experts listed above. If the coil parameters are as expected, then type

> bmwClient_script

This will initiate dithering
Observe a non-flat bpm responses on the Dihering section of the Online Data Monitor

To TURN OFF dithering:

Bring greenmonster up if it is not up already. See the section above for guidance on bringing greenmonster up, if need be.
Click on
> Toggle Kill Switch

once

Kill Switch is OFF

Kill Switch is ON

NOTE:: After every reboot of the parity daq crate (ROC 23, halladaq6, hatsv9 2004) you will need to restart dithering!

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Monitoring HAPPEX systems

To check status of feedback system and polarized source, type at shell prompt:

> runbird

Help is available using the Help button at the bottom. Settings and numbers to expect can be found in the White Bound Shift Worker Folder.

Further info about checking Feedback

   There have been several episodes of lost data because of a lack
   of vigilance on the charge asymmetry feedback.  A typical problem
   is an incorrect lobeam cut.

   Do this to check:

     1. Recent runs have a small charge asymmetry, less than 2 sigma.

     2. Look at runbird and see if it's working.

     3. "tail ~apar/feedback/feedback.log" shows recent and normal activity

   Call an expert if the results are unsatisfactory !

To set/check status of HAPPEX ADCs and timing boads, type at shell prompt:

> greenmonster

Click on tabs at top to examine ADCs in different crates or timing.

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Rebooting HAPPEX/PREX crates

If a run is in progress, end it. If you can't end it, close the CODA GUI window.
There should be xterms open for each roc in the ROCS workspace or another workspace. (If not, type "setupxterms" on apar.) In the desired xterm, click ENTER a few times to check communication to the IOC. Then type:

> reboot
The IOC will then proceed through its booting sequence. It is ready when either of these messages appear (e.g. for ROC23/halladaq6):

"ROC23" state now "booted"
Done executing startup script /adaqfs/halla/apar/vxworks/halladaq6.boot
If you cannot telnet in, it usually means someone else is telneted in.
- telnet to the portserver itself (telnet hatsv40) as root (see passwords near whiteboard). "kill tty=5" to clear port 5.
- Or someone may be telneted into the IP address ("ps awx | grep telnet" then kill -9 that pid).
- Some portservers, especially hatsv18, may need to be power cycled sometimes.

Power-Cycling the Happex/PREX Crates

Necessary when the crates get hung up, and cannot be rebooted. Do not power cycle the crates when it can be rebooted.
Go to http://g0injreboot.acc.jlab.org for Injector Crate, http://hareboot22.jlab.org for Happex right arm crate, http://hareboot2.jlab.org for Happex left arm crate, and enter the user/password which are written on the "Passwords" sheet near the whiteboard.
Click "Control Action" and select "Immediate Off", then click the "Apply" button.
Wait a few seconds, then "Control Action" and "Immediate On" and "Apply".
Where stuff located :

Crate Location	Outlet	Crate/Portserver
Injector	1	g0inj
Injector	2	happex
Injector	3	hatsv18
Right Arm	8	happex
Left Arm	4	happex

In the runcontrol GUI,

click Abort
click Reset
click Download
Sometimes it may be necessary to restart runcontrol and associated components (EB, ER, etc). The simplest way to do it is to type "startcoda". Make sure you are on apar account on adaql5.
Start a new run.

List of HAPPEX crates

HAPPEX crates
ROC	Description	Location	IP Address	Portserver
TS1	Trigger Supervisor	Counting Room	happex4	hatsv9 port 3
ROC23	CH Crate	Counting Room	halladaq6	hatsv9 port 4
ROC26	R-arm Detectors	R-HRS Det. Stack	happex7	bbps1 port 5
ROC25	L-HRS Detectors	L-HRS Det. Stack	hallavme14	hatsv40 port 5
ROC24	Happex Inj Crate	Injector Serv. Bldg.	halladaq19	hatsv18 port 4
ROC31	Qweak Injector Crate	Injector Serv. Bldg.	g0inj	hatsv18 port 5

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Running CODA for HAPPEX DAQ

Note: This is for HAPPEX DAQ. If you want to run CODA for spectrometer DAQ see Running CODA for spectrometer DAQ.

Log in, if necessary, to adaql5 as user apar
The Runcontrol GUI may be already running. If not, see section HAPPEX DAQ cold start. To start and stop runs, click on the buttons Start Run and End Run. Start Run is the same as the sequence Prestart, Go.

Be sure to enable the online data monitor before starting the run, if you wish to use it during the run.
Start a new run EVERY hour, even with no beam. Runs without beam are important for Electronics Crosstalk Analysis.

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Switching CODA config between PREX and PrexNoQweak

PREX

ROC 31

PrexNoQweak

ROC 31

Note: How to Power-Cycling the Injector Crates via http://g0injreboot.acc.jlab.org see Rebooting HAPPEX crates.
To switch the configuration (in case you cannot reboot ROC31 quickly):
In runControl, press Reset .
Click on Configuration tab, and select PrexNoQweak
Click on Download tab.
If later on, ROC 31 is rebooted, and we want to go back to PREX configuration, then follow the set of instructions outlined above replacing instances of PrexNoQweak with PREX .

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HAPPEX/PREX Data Analysis

Online Data Monitor. Click here for a one-page summary.

HAPPEX online data monitor (PANGUIN) normally starts up at start of run. To disable this "background process" enter at a shell prompt:

> panguin off

To re-enable it enter:

> panguin on

These commands have no immediate effect on analysis, but govern whether or not analysis will start at the start of the next run.
To monitor data online, log into adaql5 with the apar account and type at a shell prompt:

> gopan
> online -f prex
or

> gopan
> pan
> online("panguin/prex")

A fairly self-evident GUI will appear. Select various pages of plots using the buttons on the left.

NOTE: Please be warned that the GUI might crash for several reasons. Making it work again could simply be a matter of closing the window and restarting it. If at any point the GUI stops working and restarting does not work, then you you must do a HAPPEX/PREX DAQ cold start.

Compare histograms and strip charts of Online GUI with sample plots posted below. Inform shift leader if there is any suspectible difference.

(Updated April 16) Here is a list of plots that shift workers should look at when monitoring online data (NOTE: This data was taken from run #2822 when beam current was 30uA):

'CRUCIAL SYSTEMS'
'BCMs'
'BCM asymmetries M'
'BCM Unser'
'BPM10 wires'
'BPM12 wires'
'BPM Correlations'
'BPM vs BCM4'
'Target BPMs'

'Cavity BCMS and BPMs'
'Target BPM Diffs M'
'BPM 8/10/12 Diffs M'
'Injector BPM Diffs M'
'Injector BPM Asymmetries M'
'Blumi vs event number'
'BLumi Signals Around'
'Blumi vs BCM'
'Blumi asymN Around M'

'Blumi asymN Combos M'
'dets 1/2'
'dets 3/4'
'A_T dets'
'dets asym M'
'dets combo asym M'
'Dithering'

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Starting prompt analysis. Click here for a one-page summary.

The HAPPEX Prompt analysis is comparable to the Detector and Physics replay that is done with the Hall-A Analyzer.
- Log into adaql6 or adaql7 with the apar account.
  DO NOT PERFORM PROMPT ANALYSIS ON adaql5, adaql2 or adaql3!!!
- Do NOT do prompt analysis for a run untile it has ENDED.
- At the shell prompt, type:
  > gopan
  > prompt runnumber
- Prompt Analysis will then proceed with decoding the raw CODA data into Helicity Correlated Asymmetries and Position Differences, done by the Parity ANalyzer (PAN). This is followed by the Regression and Dithering Analysis (REDANA), which corrects the raw asymmetries for detector sensitivities to beam parameters.
- The Online GUI will open a window presenting histograms and stripcharts for the requested runnumber. Check these versus the sample Prompt Analysis plots (should be in a white bound folder). Any strange deviations from the sample plots should be brought to someone's attention (Shift Leader, Run Coordinator) and shown in the HALOG. The reference plots are shown below (the reference run 13976 was taken when beam current was around 80uA, the rate or asymmetry plotted below may vary slightly with beam current):
- If you start a prompt analysis before a run is finished, or for some reason you need to force the reanalysis of a run then use:
  > gopan
  > reprompt runnumber
- Once in a while, print out the text output files and put them in the binder (taking advantage of the opportunity to look them over and compare them to previous runs, of course). The print command is (after doing $ gopan) e.g.
  $ chaprint_text prompt_output/*_224*
  to print outputs from runs 2240 to 2249.

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Spectrometer

Bringing up the Alarm Handler

In the HAC control window, press the "Alarm Handler" label in the tools launcher. When an alarm is triggered, the bottom "Alarm Handler" will flash, then you can press there to see where the problem is.

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Bringing up the HAC control window

The machine to run HAC is hacsbc2, the second machine from left. At the bottom of the screen is the Linux taskbar. The sixth symbol is tools launcher. Pressing the arrowhead opens a menu which has:
- Alarm Handler, bogies_LEFT, bogies_RIGHT, bogies_SetSpec, JavaArchiverClient,
- Menu_Accelerator, Menu_ESR, Menu_HallA, snapshot, StripTool
Pressing the "Menu_HallA" label launches a subscreen titled "Hall A Main Menu". One of the entries is labelled "Tools". Pressing on the "Tool" button opens the "Hall A General Tools" screen as follows, which is often referred to as the HAC window. The old version of HAC can be found at http://hallaweb.jlab.org/document/OPMAN/node179.html.

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Changing momentum setting of HRS

From the HAC control window, there is a P0 SET field for each spectrometer in which you can enter the desired momentum setting. To change to a lower momentum from a higher previous setting, you just need to enter the momentum value. To bring the momentum setting up, you need to recycle the magnets for Q2 and Q3 of either arm. That is increase the current of Q2/Q3 to 1600 A for the Left arm or 1400 for the Right arm, wait for 2 minutes after they reach max, then tune down the value to the desired setting. More detailed instructions are on the white board of the counting house. There's no need to recycle magnets for Q1 and Dipole.
Procedure to reset the dipole momenta (eg. after a reboot of the magnet controls IOC):
1. Look up (in the runsheets or the whiteboard) the desired SET current in the dipole magnet power supply.
2. Turn OFF the field regulator in the dipole nmr field control gui.
3. Set the desired momentum in the hall A tools screen (set the "P0").
4. Enter the desired SET current in the dipole magnet power supply.
5. Wait for the momentum setting of the dipole to reach within ~0.5% of the desired momentum.
6. Turn ON the field regulator.
7. Eventually, the regulator will automatically enter a new set current that will take the dipole directly to the desired momentum.
  Note:
  
  left dipole SET current = (left dipole READ current)/(0.944)
  
  right dipole SET current = (right dipole READ current)/(1.005)
[This is a modified version of HAlog entry 129538].

Changing momentum setting of the septum magnets

On the Hall A Main Menu, click Magnet Controls and select BIGBOX Controls.
Enter Setpoint in Amps. The PREX production setting is 729.0 Amps.
Click Power On if necessary.
Note: Both septa are driven by the same power supply.

Reset Q1 of Left or Right HRS

From the HAC control window

This is for Q1 recovery after it trips. Never use the following instruction if Q1 works fine.

Go to Hall A tools screen and press the blue button next to "I(A)" for left or right HRS (depending on which one is having problems). Click on "Q1 power supply", this will pop up the window for power supply control.
Usually after a trip, the Q1 current will drop to zero, some fault messages will show in red, and the power supply is off. Press the "Reset" button to clear the faults and wait, for an example see halog 152379. Note that "MAGNET MISMATCH" will remain on because the current readback does not match the set point.
Try to turn on the power supply by clicking on "POWER ON". If it does not turn itself on, try the following:
Go to the middle room, look for a "Reset switch box #1" in rack CH01B04, press the green button labeled "left Q1 local control reset" or "right Q1 local control reset";
Go back to the control window and click on "POWER ON" again. If it still does not turn itself on, a controlled access is needed. In this case, consult the run coordinator first, and then go down to the hall.
1. Go to Q1 power supply, put into local mode (a button).
2. Press "reset", then "power on", then press local mode button again to go into remote (its a 2-state button). This might suffice. Ask shift crew to turn on magnet... see if it works.
3. If this doesn't work, which happens all the time, then:
  - Go to the key panel on row of equipment behind Q1 PS (toward target), press yellow button under key switch.
  - And press tiny blue reset on back of this panel. There is a big sign pointing to this tiny button.
  - Repeat step 2.
Now the power supply should be on. If it is not, you didn't do the above procedure correctly. In the control window, enter set current. If a set current is already there, check if it is the same as previous runs (check the runsheets). Wait for the magnet to ramp up.

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Target How to

PREX Cryo-Cooled Lead/Diamond Target

Main danger is the target can melt. Only source of heat is the beam.
Always keep the raster on. (4 x 3 mm²)
If the target warms up to more than 30K turn off the beam !
Checking target temperature :
- Ignore the temps in the "Hall A Cryotarget" GUI (the lifter GUI) !
- Click on Cryostat bottom, right.
- Look at Loop 2 temperatures. In this example it's 19.5 K input and 21.6 K return line.
- Most important to look at Return Line Temp on Loop 2 (here it's 21.6 K).
- These temps should be below 30 K at all times. An alarm should sound.
If you are confused about anything, turn off the beam, call the expert.
The target operator needs to know how to adjust the JT valve. That's the only control knob we have. It probably will not have to be adjusted ever, unless an expert asks for it.

Rebooting Target IOC

Go to http://hareboot7
Username and password are on the paper near whiteboard (see ioc reboot)
Select chan 5 and 6 (iocha13)
Select Control Action "Reboot Immediately".
click Next and then Apply

Restarting Target Alarm Handler

On the Hall A Cryotarget GUI click on "Alarms"
If an error message appears click "OK"
Double click on "/home/poltar/Screens/ALH".
Double-click on "atarg_PREX.alhConfig".

Alarm and Major Events

Pay attention to alarms. Make sure you know what caused the alarms and take care of them. If you are not sure, turn off beam, call the target expert.

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Spectrometer Data Acquisition

Spectrometer DAQ cold start

Note: This is for spectrometer DAQ. If you want to cold start HAPPEX DAQ see HAPPEX DAQ cold start.

To switch DAQs see the checklist to switch DAQs.
The spectrometer DAQs runs on the a-onl account. Right HRS runs on adaql2 and the Left HRS runs on adaql3.

Do the following at a shell prompt on adaql2 (adaql3) for the Right (Left) HRS DAQ on the a-onl account:

> startcoda
"startcoda" will run "kcoda", and will start all the components for you.
Run Type = LeftHRS or RightHRS.

Alternative = LeftNoGem or RightNoGem (Must use RightNoGem at the moment).
Details about Hall A Spectrometer DAQ and trigger see Bob Michaels's guide.html and guide2.html.

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Mapping of ROCs to Portserver and IP for Spectr. DAQ

HRS-DAQ CODA Configrations 

        LeftHRS or LeftNoGem       Left spectrometer DAQ       on adaql3
        RightNoGem                 Right spectrometer DAQ      on adaql2

HRS-DAQ crates
ROC	Description	IP Address	Portserver
ROC1	R-arm Lower Fastbus Crate	hallasfi1	hatsv3 port 2
ROC2	R-arm Upper Fastbus Crate	hallasfi2	hatsv3 port 8
TS0	R-arm VME/Scaler	hallavme2	hatsv3 port 3
ROC3	L-arm Lower Fastbus Crate	hallasfi3	hatsv4 port 3
ROC4	L-arm Upper Fastbus Crate	hallasfi4	hatsv40 port 6
TS1	L-arm VME/Scaler	hallavme4	hatsv4 port 7

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Triggers for PREX

We will run the spectrometer DAQ occassionally to check Q² and spot++.

Here are the triggers on each HRS

T1 = the S0 trigger
T5 = upper scintillator (above quartz)
T6 = lower quartz (for R-HRS only)

T8 = the usual 1024 Hz pulser
Recall, T9 - T12 (if exist) cannot be prescaled

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Rebooting HRS crates

Short hint: Type "reboot" at vxWorks prompts of ROC logins.
For details about Hall A spectrometer DAQ including reboot procedure see Bob Michaels' guide.html and guide2.html.

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Running CODA on Spectrometer DAQ

Note: This is for spectrometer DAQ. If you want to run CODA for HAPPEX DAQ see Running CODA for HAPPEX DAQ.

Log in, if necessary, to adaql2 (adaql3) for Right (Left) HRS as user a-onl
The Runcontrol GUI may be already running. If not, see section Spectrometer DAQ cold start. To start and stop runs, click on the buttons Start Run and End Run. Start Run is the same as the sequence Prestart, Go.
For more details about Hall A DAQ and trigger see Bob Michaels's guide.html and guide2.html.

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Starting xscaler for HRS and for PREX.

There are scalers in the HRS DAQ. To run these, login to adaql4 or adaql5 as the adaq account, type "xscaler" and follow the instructions.
For HRS you can find all trigger rates in Normalization page. For PREX, there are 4 or 5 scalers on each spectrometer with obvious tab names.

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Spectrometer Data Analysis

Analysis for Spectrometer DAQ data

Periodically there will be expert-driven runs with VDCs on and low current for the following purposes:

Q² Distribution measurement at low current.
Background Analysis.
Optics and Angle Calibration.

Instructions for Podd analysis:

Similar to other Hall A experiments that use Podd (the Hall A ROOT/C++ Analyzer)
Run on adaq account on adaql4 - 7. NOT on adaql2,3,5.
Type ``goonlana''
Type ``analyzer'' (I also have a private version which might work better: ``bobana'').
In analyzer type ``.x onlana.C'' and answer the questions.
Alternatively you can type ``do_all([run number])''.
When using "do_all", a fairly obvious GUI pops up with plots which you must check. Report all problems or strange results in the HALOG.
The ROOTfiles are stored in ./rootfiles.

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Hall A Detectors

List of Detectors

Detectors used for production running during PREX:
Main Quartz Integrating Detectors
A_T Quartz Detector

Detectors used for systematic studies such as optics or Q². (All HV must be turned off for high-rate running !)

VDCs
New GEM detectors
Scintillators

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Detector High Voltages

Hall-A Main Menu

Lecroy HV

Beamline(Compton):

Detector	Mainframe ID/Slot #	Card #	Channel #	HV (V)
Compton GSO	2	11	1	-1800
Compton Finger	2	11	7	-2000
Compton Finger	2	11	8	-1000

Right Arm Bottom:
Right Arm HV are no longer available through the Hall A Tools gui. The VNC hvgui must be used to access that HV crate. See below:

VNC HV server (R-HRS detectors)

Starting HVgui for Right HRS detector HV
- login as adev@adaql10 (passwd on wall)
- First try typing "hvgui" as adev. Actually on any machine.
- If "hvgui" does not work, try typin "start_hvgui" on adaql10 as adev. If the command fails with message that a server is already running, this may be ok. It may only mean that the server has already been launched. Or it could mean that someone is running the vt100 interface. Try the next step.
- If none of the above works, try to telnet directly, "telnet hatsv3 2005"

Careful: in the listing below, the counting of channel numbers starts with "0"; however, in the VNC display of "Measured Voltage", the numbers at the left of the table start counting at "1", so there is an offset of 1.


Info about PREX detectors from halog 313507 (but modified)


The Voltage setting are for low current HRS DAQ measurements only.

For integrating mode, the voltages are much lower -  consult an expert
for the latest settings.  Hopefully the expert will update this file.

Right Arm telnet method (deprecated)

Use the "hvgui" instructions above !!  The telnet method is a last resort   
which will render the HVgui unusable.  From an online account telnet hatsv3 2005
Once the funky "VT100" emulator window comes up, you can navigate by typing
"shift 5" to get to Card 5, "shift E" to get to Card 14 (14=E in octal), etc.
You can navigate up and down channels using the up and down arrows.
You can set a new voltage by typing the number in directly and hitting "enter".
The keys "[" and "]"will enable or disable (turn on or turn off) individual channels.

Updated 04/18/2010 by LRM Right Arm:

Name	Card	Chan	Counting Mode(V)	Integrating Mode Thick C12(V)	Integrating Mode Lead(V)
upper Quartz (det2)	14	4	-2000	-950	-840
lowerQuartz (det1)	14	6	-2000	-1000	-890
A_TQuartz	14	8	-2000	-1200	-1000
upperScint	9	6	-1400	off	off
lowerScint	9	5	-1400	off	off
s0A	15	0	-1650	off	off
s0B	15	1	-1650	off	off

Updated 04/18/2010 by LRM Left Arm: Accessible through Main Hall A Main Menu screen under LeCroy HV Left

Name	Card	Chan	Counting Mode(V)	Integrating Mode Thick C12(V)	Integrating Mode Lead(V)
lower Quartz (det3)	2	4	-2000	-960	-880
upperQuartz (det4)	2	2	-2000	-900	-780
A_TQuartz	2	0	-2000	-1200	-900
upperScint	2	10	-1400	off	off
lowerScint	1	2	-1400	off	off
s0A	13	8	-1550	off	off
s0B	13	9	-1550	off	off

Updated 04/16/2010 Right Arm (Lumi Det):

Detector	Mainframe ID Slot #	Card #	Channel #	Lead Running HV (V)	Septum On Thick C12(V)	Septum Off Thick C12(V)
Lumi #1		15	4	-600	-1170	-900
Lumi #2		15	5	-580	-1120	-990
Lumi #3		15	6	-580	-1000	-1900
Lumi #4		15	7	-810	-1865	-1800
Lumi #5		15	8	-700	-1480	-1280
Lumi #6		15	9	-700	-1600	-1500
Lumi #7		15	10	-560	-900	-1130
Lumi #8		15	11	-530	-1030	-920

NOTE: These Lumi voltages are nominally for 50 uA current.

VDC check and high voltage

VDC Status
- VDC status can be checked on the HAC control window (see below). High Voltages and Gas Flows are constantly being monitored.
VDC HV (IMPORTANT: HV must be turned off during high rate running, i.e. PREX production running.)
- Bring up the HAC control window (see below)
- In the "VDC HV" section, set HV to 0
- In the "Miscellaneous" section, click on the Crate Resets button.
- In the "Hall A Slow Controls" window, press the "Reset" button associated with the tripped HV crate.
- Go back to set HV values to 4.0 kV

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Helicity Controls

Changing the Half Wave Plate

To change the state of the insertable half-wave plate (IHWP):

Inform Hall B that we are about to change the half-wave plate. If they are in the middle of the run, then ask them to inform you when their run ends. Once we get the green light from Hall B, proceed into the following steps.
End the current HAPPEX run and the current Compton Run.
Call MCC and ask them to change the state of the Insertable Half-Wave Plate (IHWP) from In to Out or Out to In as appropriate.
When you see the state of the IHWP change in the HAPPEX feedback monitor, type in an xterm (logged in as apar, make sure to log in with the argument -Y):
flipper
The new setpoints should now appear in the HAPPEX feedback monitor.. ingeneral the Rotatable Half-wave Plate (RHWP) takes a minute or two to change, but HAPPEX III uses the same RHWP position for both HWP states.
DO NOT START A NEW RUN UNTIL YOU HAVE VERIFIED THE NEW SETPOINTS.

Start a new HAPPEX run and a new Compton Run.
Make a halog entry, saying you've changed the IHWP, and include a screen capture of the HAPPEX feedback monitor (the "runbird" GUI).
Write the new half-wave plate configuration on the white board.

Below is a sample of what the output looks like (from flipper).

[apar@adaql6 ~]$ flipper
 
****************************************
 
 Only run this program when the IHWP change has
 already been made.  If not, please Ctrl-C out now!
 
 Current slugnumber = 4
 Increment slugnumber? (Y/N)
Y
New slugnumber = 5
 
Current IHWP = OUT
Desired Settings for IHWP = OUT
     Hall-A IA = 4.79
     Hall-C IA = 5.00
     PC Pos    = 8.100
     PC Neg    = 6.610
     RHWP      = 1200
Current settings (to be changed)
     Hall-A IA = 4.79
     Hall-C IA = 5.0
     PC Pos    = 8.575
     PC Neg    = 6.125
     RHWP      = 1200
Writing the current seetings to file /adaqfs/halla/apar/feedback/IHWP.IN for the next flip back.
Performing Flip to IHWP = OUT settings
Halfwave plate OUT, Slug 5
 
Done... Please verify the new setpoints in the HAPPEX Feedback Monitor.

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PITA Scan

To measure the Polarization Induced Transport Asymmetry (PITA) slope:

End the current PREX run and the current Compton Run.
Check the status of the IHWP (IN or OUT), and set it to the state desired.
Turn off the HAPPEX feedback monitor by typing
feedback off
in an xterm (logged in as apar). You should check that the feedback status is indeed off on runbird.
Set the PC voltages appropriate for the IHWP setting. To set the voltages, open Hall Parity Controls from the Gun/Laser in the Accelerator Main Menu. We are using GUN2 currently. The voltages should be set for GUN2: PC (PITA) POS and GUN2: PC (PITA) NEG appropriately. Check the run-sheet from the previous runs to make sure the voltage you have is correct for the current IHWP setting.
If for some reason, you are not able to change the voltages on the Hall Parity Controls , call MCC and ask them to do so!

Start greenmonster from apar@adaql1 by typing greenmonster.
Go to the ScanUtil tab, and click on NOT CLEAN. Set the values on Set Point 1 and Set Point 2 to 0 . Click on Set Values, and check that the set points are indeed set to 0 by clicking on Check Status .
Start a new PREX run.
After about 200 events click on CLEAN .
After about 10000 GOOD events (beam trip events are not GOOD events), click on NOT CLEAN .
Set the PC (PITA) POS to the previous value + 1 and PC (PITA) NEG to the previous value -1 . For instance, if the previous POS/NEG were 8.5/6.2 , the new values should be 9.5/5.2 .
Set the values on Set Point 1 to +60 . Click on Set Values, and check that it is set to +60 by clicking on Check Status .
Click on CLEAN .
Repeat steps 9-12 , but setting the voltages in the opposite direction. The new set points should be POS/NEG 7.5/7.2 , and Set Point 1 at -60 for the example above.
After about 10000 GOOD events , end the PREX run, and run the prompt analysis in apar@adaql4 by doing gopan, prompt runnumber .
After the prompt replay is done, run hapPITA.C gui by typing gopan, pan, then
.x lmacro/hapPITA.C(runnumber)
Make a halog entry with the PITA slope, IHWP status, run # and the output plot of the gui with the PITA slope. Here is a typical PITA plot.

Write the half-wave plate configuration on the white board.

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HAPPEX Charge Asymmetry Feedback

For a detailed description of the HAPPEX Charge Asymmetry Feedback, look at Bryan Moffit's entry from transvertisy.

Important note about Feedback

   There have been several episodes of lost data because of a lack
   of vigilance on the charge asymmetry feedback.  A typical problem
   is an incorrect lobeam cut.

   Do this to check:

     1. Recent runs have a small charge asymmetry, less than 2 sigma.

     2. Look at runbird and see if it's working.

     3. "tail ~apar/feedback/feedback.log" shows recent and normal activity

   Call an expert if the results are unsatisfactory !

The only thing that needs to be changed after each PITA/IA scan is the feedback slope, which is done in the file panFFB.db in ~/feedback/ in apar account.
To turn charge feedback on, type feedback on
To turn charge feedback off, type feedback off
The charge feedback status should be checked in runbird , which can be brought up by typing runbird .

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Miscellaneous

Bringing up the Beamtime Counting Table

Log in to adaql1 as user adaq
Type "bta"
An attempt is made to automate the entries, but the shift leader should check it based on their own estimates of ABU, BANU, etc.

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Plotting time dependences of EPICS variables

In the HAC control window, press the "StripTool" label in tools launcher, which allows you to plot any EPICS variables versus time.

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Printing in the counting house

On hopefully all adaq computers the command print should work. Type print filename for a file named filename and it will print out on the cha2hp printer in the back room. If you want to print to another printer, type print filename otherprinter. If that doesn't work try the command line below.

rlpr -Pcha2hp -Hjlabprt file.ps

Printing from Mozilla:
- Use
  
  File->Print...
- Choose to print to printer, not file
- Click on Properties (or Configuration?) of printer
- In the field for Print command, enter:
  
  /apps/bin/rlpr -Pcha2hp -Hjlabprt
  (you should only have to do this once for each account)
- Click Print
Alternatively, you can have Mozilla print to a Postscript file, which you can then print from the command line.
Trying to print to cha2hp from a CUE machine (e.g. jlabl1) using pdq will also fail. This is not a problem specific to the counting house computers. Only lpr and rlpr will work with this printer.

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Starting HALOG

As user adaq on any adaq machine, simply type

> halog
Entering text is easy and straightforward. After submitting the entry, the white text on blue background in the lower right corner of the window should read 'Entry complete', otherwise something is wrong.
Entering graphics: Click Grab Screen in the bottom button row of the halog window. The halog window will disappear, and the window the cursor is in will become the active window, its outline flashing. You can select any window by clicking in it on the left mouse button. You also can select an arbitrary part of the screen by holding down the left mouse button and dragging the cursor along. All the time a rectangle will flash that indicates the selected area. Releasing the mouse button will then cause this screen area to be included into the entry. It will show up as a thumbnail picture in the halog window, where you can discard it or accept it, or go for a second screen grab. The images are in GIF format.
For more details about HALOG see halog HOWTO and FAQ page.

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Starting `spot++` and checking the raster

Log in to as adaq on adaql4 or any other adaq Linux computer.
Make sure CODA is running with beam on. Of course, that's the spectrometer DAQ, not the PREX DAQ. You'll need some triggers (adjust prescale factors to get at least 50 Hz of something, if possible).
If you ran the L-HRS DAQ, type spot_L runNumber from any directory, after about 30 seconds, plots will pop up.

Recommend to stick with L-HRS DAQ, but if you did use R-HRS DAQ then type spot_R runNumber
You can get "strange printouts" of errors if you only type spot++ and the last run was for R-HRS, so it's clearer to do what is listed above than to use spot++. (note, this is because spot++ is actually spot_L).
Hint: Type "spot help" to learn more options.

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How to Cycle Quads `Q2` and `Q3`

Turn off the regulator (click GeV/c button on magnets screen to the things to click)
Q2 is presently limited to 1000A. Here is how to cycle (halog 312896): Ramp up to 1000A and back to zero. Repeat this a 2nd time, then go to the desired setting.
For Q3 the cycling procedure is normal: ramp to 1400A, then go back to the desired setting.
Don't cycle Q1.
Turn on regulator

PREX "How To" Page

HAPPEX/PREX Data Acquisition

HAPPEX/PREX Data Analysis

Spectrometer

Target How to

Spectrometer Data Acquisition

Spectrometer Data Analysis

Hall A Detectors

Compton Polarimeter

Helicity Controls

Miscellaneous

Other Problems

Shift Worker Responsibilities

Shift Leader:

Target Operator:

Third person:

HAPPEX/PREX Data Acquisition

To check the current dithering status:

To TURN ON dithering:

To TURN OFF dithering:

HAPPEX/PREX Data Analysis

Online Data Monitor. Click here for a one-page summary.

Starting prompt analysis. Click here for a one-page summary.

Spectrometer

Target How to

PREX Cryo-Cooled Lead/Diamond Target

Spectrometer Data Acquisition

Spectrometer Data Analysis

Hall A Detectors

Helicity Controls

Changing the Half Wave Plate

PITA Scan

HAPPEX Charge Asymmetry Feedback

Miscellaneous

Other Problems