sPHENIX tracking discussion

["Yasuyuki Akiba" <akiba AT rcf.rhic.bnl.gov>]

Dear John and Walter

I can provide answers to many of your questions on the pixel
reconfiguration.

1. configuration of the reconfigured pixel
We need to start on this very soon. I think the 13/19 proposal from Mike M
is a very good point. I propose that this to be the default and want to
start the mechanical engineering based on this model of 13 p0 and 19 p1
configuration.
This means that the radius of new p0 is 2.48cm and that of new p1 is 3.63cm

2. How layers will be constructed
This is exactly the work we need an mechanical engineer. I suppose we follow
a similar design as VTX, namely, the ladders are supported by barrel mounts
at the both ends. So we need a design of barrel mount of new 13 ladder p0
and 19 ladder p1. Perhaps each are divided into two asymmetric pieces (6+7
and 9+10). But these details and the assembly procedure is the job for an
mechanical engineer and designer.

3. Cooling      We are using the same ladders. So as the default I think we
will use Novec coolant, unless there is a better one proposed.
We had a lot of trouble in the cooling manifold for the VTX. I now think
that part of those troubles comes from the lack of good engineering. The
cooling pose a systemic risk -- if it fails, the entire detector can be
affected. We need better cooling manifold and piping designed this time.

4. Structural goal--- low mass and stable
Yes.
The material thickness in the sPHENIX acceptance is fixed. It is the
thickness of the existing ladders, and it is 1.3% per layer. The ladders
will be supported a the both ends outside of the |eta|<1 sPHENIX acceptance,
and there is no detector behind. We need to make the ladders stable and this
is the primary goal.

5. SPIRO boards
I think we have 40+ SPIRO boards. Some of them were broken. But I believe
that we have 32 boards needed for the 13/19 configuration plus spares. To
eric...How many SPIROs do we have?
I think the default positon is to use the SPIROs as it is. This probably may
not be ideal way but it is cheapest. Alternative is to make new SPRIO
boards, which requires additional electrical engineering work and
fabrication cost. In addition, some of the components used in SPRIO (e.g.
analog and digital pilot chips) are not available any more. So, if we take
the alternative route, we need to salvage those chips from the existing
SPRIO boards. I think we assume that we use the existing SPIRO boards as the
default option. Then we need a mechanical engineer/designer to find out
where those boards can be placed and supported. 

In addition,

* Bus extenders
We need to make new bus extenders. I don't think this is difficult nor
costly. We first need to find out how long the bus extenders need to be. The
location of the SPIRO will determined the length.

* Mechanical independence of the pixel subsystem
I cannot imagine that the pixels will be used in ePHENIX era. That time, the
pixel ladders will be more than 15 years old. So the pixels and its support
and electronis support should be designed as mechanically independent with
other part of sPHENIX so that the entire pixel subsystem can be removed from
sPHENIX. Such design allows that pixels can be replaced with other internal
tracker like MAPS if it becomes available.

Sincerely yours,
        Y. Akiba
-----Original Message-----
From: sphenix-tracking-l-bounces AT lists.bnl.gov
[mailto:sphenix-tracking-l-bounces AT lists.bnl.gov] On Behalf Of Sondheim,
Walter E
Sent: Tuesday, November 17, 2015 12:08 PM
To: Sphenix-tracking-l AT lists.bnl.gov
Subject: [Sphenix-tracking-l] FW: sPHENIX tracking meeting next week



-----Original Message-----
From: Sondheim, Walter E
Sent: Tuesday, November 17, 2015 9:40 AM
To: 'John Haggerty' <haggerty AT bnl.gov>; Itaru Nakagawa <itaru AT bnl.gov>
(itaru AT bnl.gov) <itaru AT bnl.gov>
Cc: 'sphenix-tracking-l-bounces AT lists.bnl.gov'
<sphenix-tracking-l-bounces AT lists.bnl.gov>
Subject: RE: [Sphenix-tracking-l] sPHENIX tracking meeting next week

Dear John and Itaru, I am glad to see you have both reached a similar
conclusion that the sPHENIX tracking discussion certainly should include
engineering support, weather it is on project or off. I also know that both
Mike McCumber and Yasuyuki Akiba have been in discussion concerning how the
current pixel ladder design can be reconfigured to give to hermetic layers.
There are some basic parameters that need to be decided on first - from an
engineering standpoint; Given that the goal is to have two hermetic layers
around the beampipe - 1, What is the radius that these two layers should be
configured for (currently the pixel sensors are at a radius of 25.0 and 50.0
millimeters respectively).
2, How will these layers be installed/constructed? Will they be continuous
barrels that will somehow be placed over the beampipe by breaking the
vacuum? Will they again need to be made in sections as they are currently? 
3, Cooling - will these ladders again be cooled using 3M Novec coolant? 
4, Will the structural goal again be low mass and stable - leading again to
a carbon composite type of structure.
5, Additional ladders mean additional Spiro boards, additional cables,
additional mounting plates?
These are just a few points that come immediately to my mind - I am sure
there may be more - specifically if there are additional layers for
tracking, how will these layers be tied to the inner two layers of pixel
ladders? 
Cheers,
Walter

-----Original Message-----
From: sphenix-tracking-l-bounces AT lists.bnl.gov
[mailto:sphenix-tracking-l-bounces AT lists.bnl.gov] On Behalf Of John Haggerty
Sent: Tuesday, November 17, 2015 7:25 AM
To: Itaru Nakagawa <itaru AT bnl.gov>; sphenix-tracking-l AT lists.bnl.gov
Subject: Re: [Sphenix-tracking-l] sPHENIX tracking meeting next week

Itaru,

Yes, you're right, there is a mechanical engineering component that we'll
have to get you help for here at BNL, but we're going to need to provide him
or her with not only the existing drawings but guidance about what is
actually possible to do in reconfiguring the pixels, for example, what kind
of cable extensions are workable, where we can relocate electronics, and so
on.  It seems to me that ideally, one would try to set up a ladder on the
bench with something like the configuration needed in sPHENIX to make
certain that the putative rearrangement would actually work before we
engineered a final design.

There may be other or better ways to proceed, but we definitely have to
start figuring out exactly what we want to do, and then try to create a team
of experts who can help design and eventually accomplish it.

This would be a good topic for the tracking meeting on Friday;
unfortunately, I have been unable to attend the last few of these, and I'm
going to miss Friday's meeting as well, although the training I'm missing it
for will allow me to resuscitate anyone who develops heart failure from
thinking about it.  I will try to attend these meetings in the future.

On 11/17/15 12:10 AM, Itaru Nakagawa wrote:
> Hi John,
>
>   Regarding reconfiguring pixel sensors, this job is mostly engineering.
> As you guys familiar, we don't have any mechanical engineers employed 
> in RIKEN. This is quite inefficient job for us to pursue.
> As the matter of fact that the last cost and schedule reviewers 
> recommended that pixel reconfiguration should be in the scope of the 
> sPHENIX project, we strongly believe that this is the job that BNL 
> should take a responsibility.
> We of cause are still responsible to make ladders available.
>
> Regards,
> -itaru
>
>
>
>
> On 2015/11/14 0:45, John Haggerty wrote:
>> Itaru,
>>
>> No, certainly nobody would suggest that you spend any time evaluating 
>> MAPS detectors, but starting from the pixels, we need to know soon is 
>> how feasible *is* the reconfiguration of pixels?  Specifically, we 
>> need to be able to show:
>>
>> 1- A mechanical design that shows all the available ladders 
>> configured into a 2*pi detector
>>
>> 2- We need to know how the electronics will be configured to read it 
>> out--where will it go?  Are there problems with a new configuration 
>> of the readout electronics (longer cables leading to reduced 
>> performance, noise pickup, or crosstalk)?
>>
>> 3- Is the cabling feasible?  Do cables come out both ends?
>>
>> 4- How is the detector supported, inserted, and removed?
>>
>> And, of course, last, but not least, how much does it all cost, and 
>> how long does it take?
>>
>> Item #1, 3,  and 4 probably takes a mechanical designer; we may have 
>> to work with you to provide such a person, although you may be able 
>> to do it yourself, I'm not sure what the state of the mechanical 
>> model is.  I would think that #2 would be best addressed by bench 
>> tests on a spare ladder.  And when we know those things, then we can 
>> feed the real pixels back to Tony so we can see how it performs.
>>
>> Of course, the outer layers need the same treatment, or more, since 
>> there are many new ideas and components, but it seems to me we need 
>> to develop more complete answers to these questions for the pixels 
>> straight away.
>>
>> On 11/12/15 11:53 PM, Itaru Nakagawa wrote:
>>> Hi Tony,
>>>
>>>    OK.
>>>
>>> -itaru
>>>
>>> On 2015/11/12 23:49, Frawley, Anthony wrote:
>>>> Dear Itaru,
>>>>
>>>> We have a group (LANL) who has a strong interest in a MAPS inner 
>>>> tracker, so this is of considerable interest to them.
>>>>
>>>> There is no suggestion that you guys should spend time studying a 
>>>> MAPS tracker.
>>>>
>>>> Cheers
>>>> Tony
>>>>
>>>> -------------------------------------------------------------------
>>>> -----
>>>>
>>>> *From:* Itaru Nakagawa [itaru AT bnl.gov]
>>>> *Sent:* Thursday, November 12, 2015 10:09 PM
>>>> *To:* Frawley, Anthony; sphenix-tracking-l AT lists.bnl.gov
>>>> *Subject:* Re: [Sphenix-tracking-l] sPHENIX tracking meeting next 
>>>> week
>>>>
>>>> Hi Tony,
>>>>
>>>>    I don't think we (RIKEN group) are the one who look into the 
>>>> MAPs option by spending our limited man power to do the study at 
>>>> the cost of slowing down the development of the silicon strip.
>>>> However,  I am open to *listen* to the idea to make the outer 
>>>> tracker with MAPS from anybody who comes up with the
>>>> 1) cost  and 2) schedule estimate in the level of reality of what 
>>>> we have for the silicon strip solution.
>>>>
>>>> Regards,
>>>> -itaru
>>>>
>>>>
>>>>
>>>>
>>>> On 2015/11/12 15:25, Frawley, Anthony wrote:
>>>>> Hi All,
>>>>>
>>>>> First, a reminder that the next sPHENIX tracking meeting will be 
>>>>> November 20 (not tomorrow!).
>>>>>
>>>>> For our meeting on November 20, we have arranged for Luciano Musa 
>>>>> to call into the meeting at 9:00 am to give us a presentation 
>>>>> about what would be involved for us to implement MAPS pixels in a 
>>>>> tracker for PHENIX. This follows up on discussions with Leo 
>>>>> Greiner in Santa Fe, where he talked about some cost comparisons 
>>>>> of strips and MAPS pixels indicating that they would have similar
cost.
>>>>>
>>>>> In addition to the discussion with Luciano, which should be quite 
>>>>> interesting, I will also be soliciting presentations from experts 
>>>>> on all four tracking options.
>>>>>
>>>>> Cheers
>>>>> Tony
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
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>>>>> Sphenix-tracking-l AT lists.bnl.gov
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>>>
>>>
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>>
>


--
John Haggerty
email: haggerty AT bnl.gov
cell: 631 741 3358
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