Meson Hall Users: T2/M9 vacuum leak and possible impact on Schedule 119b and 120

[Science Division]

Dear TRIUMF Users, Experimenters, Operators and Staff,

We have been informed that the T2/M9 indium vacuum seal appears to have 
a vacuum leak which potentially can jeopardize operation of BL1A. It was 
found that the level of vacuum leak depends on thermal changes, hence is 
worse without beam on T2 than with beam. The Accelerator Division has 
worked on various scenarios to maintain operation and to minimize the 
impact on the science program. We have agreed to move forward in the 
following ways:

Additional tests are needed to determine if operation is possible, 
including running with deteriorated vacuum and possible high air 
activations. These tests are scheduled to minimize the risk to the 
ongoing program, as such they are scheduled for the next ion source 
change: September 13, 2011.

If these tests are successful we plan to continue with the current 
Schedules 119b and 120 (presently still in draft form). Experimental 
beam operation will start October 5th, hence this will have no impact on 
the meson hall experimental program.

If these tests are not successful we would immediately start a process 
to blank off T2/M9. This process would take about 4 weeks, and would 
start with the currently scheduled cool down period and only low 
intensity operation of BL1A. The main impact would be a delayed start up 
for BL1A around October 20th (instead of October 5th). M9 would not be 
available for experiments on Schedule 120. Experiments on M11, M13, and 
M15 would be impacted and we are considering a re-arrangement of the 
schedule so that the experiments with the highest priority are run, and 
therefore we would have to cut some experiments that are ranked at lower 
priorities. Soon, we will distribute a draft schedule with these 
re-arrangements in the case of an unsuccessful test.

If a catastrophic failure occurs prior to the test on September 13th we 
would have to go directly into low intensity mode at this point. We 
would start the blank off procedure, stop beam production for M9, M11, 
M13, and M15 and come back with operation after the shutdown on October 
20th.

My apologies for the inconvenience and appreciate your understanding 
while we are doing our best to find solutions to these BL1A related 
technical difficulties in high radiation areas. As in the past I try to 
provide full transparency and I am happy to discuss you questions or 
concerns.

Jens Dilling
(sent by Niki Martin)

-- 
Miss Nicole (Niki) Martin
Administrative Assistant, Science Division

TRIUMF
Accelerating Science for Canada | Un accélérateur de la démarche scientifique canadienne
4004 Wesbrook Mall
Vancouver, BC  V6T 2A3
Tel:  604-222-7438
Email:  nmartin at triumf.ca