Difference between revisions of "Minutes-8-27-2015"
(→Electronics) |
|||
Line 27: | Line 27: | ||
The signals are still low enough (~100mV) so this is not a saturation effect (Fernando). Most likely it comes from ion tails (Lubomir), however it is not clear why it happens mostly in the CDC, is the ion-cancellation different in the two detectors? | The signals are still low enough (~100mV) so this is not a saturation effect (Fernando). Most likely it comes from ion tails (Lubomir), however it is not clear why it happens mostly in the CDC, is the ion-cancellation different in the two detectors? | ||
− | - Nick: all "noise-reducing" elements from the CDC were removed. Tim is informed about that but | + | - Nick: all "noise-reducing" elements from the CDC were removed. Tim is informed about that but needs to decide about the installation of an additional Al-foil target before inserting the target back. Nick replaced one LV module in the CDC; it was giving high current without any load. This is the second problematic LV module, the first one had different issue. |
- The PR for 100 spare pre-amps was approved. | - The PR for 100 spare pre-amps was approved. |
Revision as of 14:34, 28 August 2015
August 27, 2015 Drift Chamber meeting
Contents
Connection
- Instructions for Bluejeans meeting connection
- Meeting ID: 290664653
- To join via a Web Browser, go to the page [1] https://bluejeans.com/290664653.
Agenda
- Electronics
- CDC update (Mike, Simon, Beni)
- FDC update (Luke,Lubomir)
- fall2014 vs spring2015 offsets
- Tagger Tests with Fe source: [6][7][8]
- Engineering
- Other
Minutes
Participants: Curtis, Mike, Naomi (CMU), Fernando, Eugene, Luke, Beni, Dave, Chris, Nick, Simon, Sergey and Lubomir (JLab).
Electronics
- Fernando studied the noise on the CDC and FDC together using two differential probes: see scope pictures linked in the agenda. First picture shows the noise levels in the two detectors are similar; FDC looks better but not by a lot. The second and third pictures show typical cosmic signals with correct timing. Last plot discussions - occasionally there are long tails in the CDC signals (~5 usec). The signals are still low enough (~100mV) so this is not a saturation effect (Fernando). Most likely it comes from ion tails (Lubomir), however it is not clear why it happens mostly in the CDC, is the ion-cancellation different in the two detectors?
- Nick: all "noise-reducing" elements from the CDC were removed. Tim is informed about that but needs to decide about the installation of an additional Al-foil target before inserting the target back. Nick replaced one LV module in the CDC; it was giving high current without any load. This is the second problematic LV module, the first one had different issue.
- The PR for 100 spare pre-amps was approved.
CDC update
- Simon continues to study the tube deformations using beam data. So far he checked rings 1 to 7 and 13. Ring 7 (stereo) looks worse and there's a straw with more than 1mm deformation.
-
Electronics
- Eugene reminded about the deadlines for the end of the FY15. The PR for the 100 spare pre-amps is out.
FDC update
- Alignment offsets for the spring run different by up to 300 microns from the ones in the fall. Most likely this is due to the bias in the fall trigger.
- Using 55Fe source on the 4.5mm-thick cell results in very broad (in time) argon peak. The max drift time for the 40/60 gas is huge, ~20 microseconds which, at least partially, may explain this effect to be related to the longitudinal diffusion. Conclusion: need faster gas for the TRD test this fall, most likely 90/10 Ar/CO2.
-->