Minutes of Meeting: May 28, 2009
Attendees = Bickley, Mittig, Pollacco, Roussel-Chomaz, Sakurai
I. ASIC
- LP and WM will perform a final physics review of the specifications in the next ~week
- design implies electron amplification provided by either GEMs or uMegas
- at high rates the signal from wires will undershoot baseline
- need to examine whether pole zero compensation will be sufficient to correct particularly in pileup situations
- must confirm with ED that the chip design will accommodate the inclusion of resistive sheets in the future
- Bordeaux will build an optional preamplifier that will sit between the pad and the filter
- must confirm that a switch is still included between the preamp and filter that allows the system to be run in current mode
pad-------->preamp-------->filter-------->SCA---------->
| |___________/ ________|
| |
|_______________/ _____________|
- confirm if 500us tail is corrected
- if the preamp is used w/o the filter saturation may occur
- tests should be conducted with AFTER to determine if this is a problem
- ED has a solution for this problem but there is not sufficient time to implement it before the first submission
- LP and WM will determine if track perpendicular to the pad will saturate the preamp
- should test AFTER with a wireplane to determine issues important to the Riken chamber
- all final decisions and tests must be completed by Dec to be included in the second submission
- must examine if saturated pads impact neighbors
- the filter shaping time is dependent on the angle of the track because the preamp integrates all incoming current
- this could be a problem if the preamps saturate
- need to confirm that the shaping time is correct (100ns→1us, 121fC & 10pC)
- if the shaping time is consistent with the width of the input signal then the resolution becomes poorer for longer shaping times
- the max size of the pad will not be dependent on the max shaping time bc the option exists to integrate
- WM will estimate errors for this type of situation
- could expand the max shaping time to 2us
- need to determine if there are problems for slow drift gases such as H2
II. ASAD
- board will likely be thicker than that of T2K bc it will be necessary to reduce noise
- ASAD design has been modified to include an FPGA to handle slow-slow controls
- will not interfere with analog bc changes are only made when data is not being written
- power must be supplied independently to the ASAD (not through the CoBo) need estimate of magnitude required
- FD has information regarding T2K cooling scheme
- Triumf worked on the T2K gas filtering and recirculation system
- ASAD will be designed to send the signal 5m, but will be operated with a 3m max cable length
- this will require repeaters be included on the board which require a large amount of power
- power supplies can have extended cable lengths
- LP is considering the requirements for a portable daq system that can be plugged directly into ASAD
- perhaps this is something Riken would be interested in?