LN system

Gammasphere's detectors need to be filled with Liquid Nitrogen at least twice a day. Because there are up to 110 detectors, a hardware system has been created to mechanize this process. This page outlines the access to and usage of this system.

Access to the LN fill system from outside

To access the LN fill EPICS pages from outside, do the following

• ssh -X [email protected] (or ssh -x gamop@ln2con, where findhose works)

• ssh -X dgs@dgs1

• launch the LN EPICS control pages by typing 'lnmain'

If you do not have an account on sonata, the (green) gateway machine to onenet, you should talk to Ken Teh about getting an account on the machine

The Lnfill Console Window

Type

 cu -s 9600 -l /dev/ttyS0

on ln2con.

When do I have to reboot the lnfill IOC?

When there is a valve overtime, it is necessary to reboot the IOC for the alarm to the dialer to reengage.

If it is just a temperature alarm, it is not necessary to reboot the IOC

How Do I Fill One Detector Remotely?

This is typically done if a detector warms up before the next fill or after a problem like a clogged bayonet has been fixed.

Locate the EPCICS control screen for the detector in question, then

• open the valve for tank you want to use
• and the associated exhaust valve for the line
• wait for the temperature at the exhaust valve to bottom out (meaning that there is now liquid there)
• put the exhaust valve back into 'auto mode' again
• open the valve to the detecor you want to fill
• wait for the temp at the detector return to bottom out (meaning that there is now liquid there)
• return the detector valve to 'auto mode'
• return the tank valve to 'auto mode'

o Analog Gammasphere

What Do I Do About Overtimes?

• Clean bayonet
• Check for leaks in line

When you have solved problem, do a manual fill and don't forget to reboot the IOC.

What Do I Do About Undertimes?

• Fill manually after the tank fill!? Or bad sensor? NOT SURE
• Reboot lnfill

Case of Blown Fuse on AB

If a number of detectors have overtime in the same manifold, there may be a blown fuse on an AB module. Look for red 'fuse'. Replace fuse and locate the bad valve. Then switch to another fill line and disable the bad valve that caused the short.

Detector No. and Fill Line

On ln2con you can say 'findhose' to determine what fill line belongs to the detector that is warming up.

How To Set the Temperature Thresholds

  To see the current temperature and the alarms limits, as gamop on
  ln2con, do this (shown for det 107)
  
  cd /home/gamop/lnfill_logs
  
  set_hilo_lim 107
  MOD107_DV_TEMP.HIHI            91
  MOD107_DV_TEMP.HIGH            86
  MOD107_DV_TEMP                 78.4094
  MOD107_DV_TEMP.LOW             66
  MOD107_DV_TEMP.LOLO            61
  
  to change the limits so HIGH is 78+10, LOW is 78-10, HIHI=78+20 and LOLO
  is 78-20, type this:
  
  set_hilo_lim 107 78
  Old : MOD107_DV_TEMP.HIHI            91 
  New : MOD107_DV_TEMP.HIHI            98 
  Old : MOD107_DV_TEMP.HIGH            86 
  New : MOD107_DV_TEMP.HIGH            88 
  Old : MOD107_DV_TEMP.LOW             66 
  New : MOD107_DV_TEMP.LOW             68 
  Old : MOD107_DV_TEMP.LOLO            61 
  New : MOD107_DV_TEMP.LOLO            58 
  
  after that you will see:
  
  set_hilo_lim 107
  MOD107_DV_TEMP.HIHI            98
  MOD107_DV_TEMP.HIGH            88
  MOD107_DV_TEMP                 78.2947
  MOD107_DV_TEMP.LOW             68
  MOD107_DV_TEMP.LOLO            58
  
  One should set these limits when the detectors are nice and cold.

misc

• do not start a full fill of GS from 8pm to midnight while GT is present
• if a detector starts to warm up less that an hour before the next fill, it is best to leave it alone and wait for the fill. That is to avoid fill under-times at the regular fill which will just cause other problems

Go back to Digital Gammasphere Upgrade Project