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[Takao Sakaguchi <takao AT bnl.gov>]

Hi Tom,

 I see. I agree that we place 16 pads in radial direction for each R segment

regardless of the radial width.

 I think it is fine. Also, I think this design concept is enough for CD-1 review.

Takao

On Thu, Jan 5, 2017 at 1:00 PM, Thomas K Hemmick <hemmick AT skipper.physics.sunysb.edu> wrote:

Hi Takao

I have a minor disagreement with this figure.  The statements like 20-40, 40-60, and 60-80 are all ROUND numbers.  They are not really exact numbers of cm.  For this reason, dropping the number of pad rows in the outer-most module is not correct.  There will be 16 radial segments in every module.  Each module will be LESS than 20 cm, but they will all be equal size.  Furthermore, we still need to leave a little room for services (like gas in/out and laser in/out) and so even taking 78-20cm and dividing by three is a little bit too big.

This, the correct segmentation is the slightly larger on that was suggested on the spreadsheet at the end of our December meeting.

OPTION 1:

R1:   6 cards/R1  *  12 R1/end * 2 end/TPC = 144 cards/TPC

R2:   8 cards/R2  *  12 R2/end * 2 end/TPC = 192 cardsTPC

R3: 12 cards/R3   * 12 R3/end * 2 end/TPC = 288 cards/TPC

TOTAL = 624 cards/TPC * 8 SAMPA/card = 4992 SAMPA/TPC * 32 channels/SAMPA = 159,744 channels/TPC

OPTION 2:

R1:   5 cards/R1  *  12 R1/end * 2 end/TPC = 120 cards/TPC

R2:   8 cards/R2  *  12 R2/end * 2 end/TPC = 192 cardsTPC

R3: 12 cards/R3   * 12 R3/end * 2 end/TPC = 288 cards/TPC

TOTAL = 600 cards/TPC * 8 SAMPA/card = 4800 SAMPA/TPC * 32 channels/SAMPA = 153,600 channels/TPC

One should note that, even though we will have 48 channels in radius, we will only include 40 radial channels in the datastream.  This is VERY VERY close to what we have been talking about thus far as being 30 radial segments.  The wiring of 30 segments would have been a NIGHTMARE and now it is a dream, so this is a very good compromise.

Tom

On Fri, Dec 23, 2016 at 10:23 AM, Takao Sakaguchi <takao AT bnl.gov> wrote:

Dear All,

 Tom, Klaus and I had a discussion on the readout pad
configuration for the TPC on Wednesday, and converged into

a sort of realistic configuration, which nicely matches the

FEE card configuration.

 I here tried to illustrate in a drawing with some explanation

and a channel count as attached. Currently, if we fully

instrument pads down to 20cm for both sides, the number

of readout pads will be ~150K and the number of FEE cards

will be 600. which is ~50% more than the reported values.

Given the good price of DAM and EBDC modules, we may

be able to accommodate this channel increase.

 Here is some detail info in the pad configuration.

 Right now, our engineers designed the pad plane support

structure in the unit of 30 degree in phi and 20cm radius

width. So, we tried to place pads in multiple of of the number

of channels of a FEE card, which is 256 channels.

 In this manner, we set the radius length of the pads as

12.5mm so that the 16 pads will be in line in radius direction

in 20cm radius width.

 In phi direction, the number of pads will also be multiple of

16, so that the number of pads in a give sector will be

multiple of 256. The pad size will change as a function of

radius in a given sector.

 In this configuration, we place 5, 8 and 12 FEE cards in a

given sector for 20<r<40, 40<r<60, and 60<r<78cm radius

regions, respectively.

 The most outer ~20cm ring will be 18cm indeed, so, the

each FEE will handle 14*16 instead of 16*16 channels.

We could work out to minimize the free channel of the

FEE card. 

 I'll work on the configuration of the FEE card for this case

as well as the expected data rate from each FEE card soon.

 Have a happy holiday!

Takao

--

Takao Sakaguchi
Brookhaven National Laboratory
Physics Department, Bldg. 510C
takao AT bnl.gov
Office: 1-631-344-3345

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--

Takao Sakaguchi
Brookhaven National Laboratory
Physics Department, Bldg. 510C
takao AT bnl.gov
Office: 1-631-344-3345