GlueX TOF Meeting, April 25, 2013
GlueX TOF Meeting
Thursday, April 25, 2013
10:00 am EDT
JLab: CEBAF Center, F326/327
- Review of last TOF bi-weekly meeting
- Construction news
- Invoicing changes and status
- Installation plan and document
- Go to http://esnet.readytalk.com
- In the "join a meeting" box enter the code: 1833622
- Fill in the participant registration form.
Talks can be deposited in the directory
/group/halld/www/halldweb/html/talks/2013-2Q on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2013-2Q/ .
- FSU: Paul Eugenio, Sasha Ostrovidov
- JLab: Eugene Chudakov, Chuck Hutton, Mark Ito (chair), Beni Zihlmann
- FSU has been spending time improving equipment in the lab.
- The wrapping table needed additional central legs to improve stiffness.
- Ian constructed three additional gluing fixtures (for gluing PMTs to modules)) to bring total to five, so that five modules can be glued at one time. Unfortunately, an endcap piece was missing, so this has introduced delay while waiting for delivery. After the fixtures are complete, and five modules are completed, they will be tested.
- The storage lab has been re-arranged by Maurizio to accommodate more shelves, increasing capacity. Right now the room has a majority of the scintillators.
- Testing of scintillators continues.
- Sasha has to change electronics to do complete module testing, so for now he is trying to get ahead on scintillator testing while that set-up is in place.
- Twenty-five bars have been tested. Only one bad bar was found (reported last time), with an attenuation length of 150 cm. Good ones show 250-400 cm. The specs is greater than 200 cm.
- Beni commented on the large range in attenuation length. The documentation from Eljen on these bars shows similar variation and the tests are consistent with that documentation. Paul also noted that the six first-article pieces were from one or two batches while the production pieces are from several. Eugene remarked that the variation in attenuation is likely due to variations in surface quality after the diamond cut, though Paul reported that visually at least, no large variations have been seen. Eljen also said that the one bad came from near end of of a production batch where color changes can happen.
- FSU is using a new method for wrapping the modules with ESR. Previously sutures were used to tighten the material. Ian has made a fixture that allows pre-folding of the ESR to its final shape. This saves time taping up the seam later, although the over-all procedure takes about the same amount of time. On the other hand, the pre-folded sheets can be done in bulk and saved for taping later.
- Sasha described an algorithm for matching PMTs in pairs to be used on modules. The goal is to put together PMTs that have similar gain, but dissimilar noise levels. The latter requirement insures that no single module has a noisy tube on both ends. For details see his webpage.
- FSU has received the flash ADC 250 from JLab. They also got a copy of the driver from David Abbott. Sasha will start work on modifying it to use their CAEN VME controller.
- With the added ADC channels Paul and Sasha are considering testing six modules at one time a la Ralf Gothe at South Carolina. That would saturate the high-voltage channels they have in their LeCroy 1458 mainframe. Mark will look into getting a module to loan to them.
Invoicing changes and status
JLab has not received any of the detailed invoices agreed to at the readiness review. Paul will check on this at FSU. Mark will ask Kathleen Jones if direct contact between her and FSU would be useful.
Installation plan and document
- FSU plans to map the locations and orientation of individual modules in advance of shipping to JLab. Modules will be shipped in batches. There is shelf space at FSU for about half of the completed modules, although if needed, more storage can be found. Storage at JLab has not been worked out. Maurizio is looking in the size of the boxes. JLab needs that information to plan.
- We will test each module after shipping to make sure it survived the trip.
- Tim has started having assembly and installation meetings for the TOF. The last one was attended by Tom Carstens, Chuck, and Mark. We will try to connect FSU to the discussion in some manner soon.