1. - STT LAYOUT - SECTOR F SECTOR A SECTOR B SECTOR E SECTOR D SECTOR C9 18 25 30 33 37 36 35 34 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
2+4 1
2+2,5+5,20,21,22,23,24,25,26,27
28,29,30,31,32,33,34,35
SECTOR B
SECTOR E
37,38,39,40,41,38,33,30,25,18,9 1
2+4 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 33 34 35 36 37 30 25 18 9
SECTOR D
SECTOR C
Slide from P. Wintz
straws per semi-barrel

2. - ELECTRONICS REQUIREMENTS AND CONSTRAINTS -
- The STT readout ASIC will provide LVDS differential outputs.
- It will have 8 channels/chip and 2 control lines.
- Therefore for each chip we will need a 10 pairs flat cable.
- Four regions are available for the STT services: Top and Bottom,
Left and Right.
- We decided to route LVDS cables in the Left/Right cutouts, HV and gas
pipes will be placed Top/Bottom.
We have to keep some “free” space in the Top/Bottom housings since no safety margin has been considered, temperature an pressure controls will be needed.
The design of the electronic boards is still ongoing it could turn out that more space would be necessary.

3. - CABLES ROUTING SYSTEM: - Routing ways, final dimensions (green lines).
Top & Bottom Routing way.
Available Cross Section: 1800mm^2 55 85
R443
410
120
410
120
- Routing ways final arrangement:
dimensions in detail.
Lateral Routing way.
Available Cross Section: 6600mm^2

4. - PATHWAYS OF FLAT CABLES BUNCHES -
-The encumbrance of the connectors
has not been considered! 24
- Flat cable cross section (8,5)10mm^2/each
(In twisted region of the cable)
- Total: 10x296 = 2980mm^2 17
- Weight: kg/m 95 19 13 13 22 9 54 41 53 17 14
296 Flates
(2960 Ch.)
106 13 17
0,65mm 54 41 53 9 23
in reality we would have had considered 3478 = 2318 tubes control lines
The surface of the Left and Right cutouts is 6600 mm2 13
13mm 19 13 95 17 24

5. - FLAT CABLE CONNECTORS -
ELECTRONIC CARD CONNECTOR
25,5mm
FLAT CABLE CONNECTOR
10mm
7mm
13,5mm
E_Card
30mm
6,6mm
- Approx. weight of connector: 3g / Each

6. - PATHWAYS OF HV CABLES AND GAS PIPES -
-The encumbrance of the
connectors has not been
considered!
20 HV Cables
4 Gas Pipes
(From the Forward Side)
HV CABLE DATA
- Cross Section 8,1mm^2/each
- Total: 8,1x20 = 162mm^2 (Each Pathway)
- Weight: 0,0162 Kg/m
13 HV Cables
8 Gas Pipes
(From the Forward Side) 13 7
13 HV Cables 6
8 Gas Pipes
(From the Forward Side)
The surface of the Up and Down cutouts is 1800 mm2 each 13
GAS PIPE DATA
13 HV Cables
- Cross Section 28,26mm^2/each
- Total: 28,26x12 = 340mm^2 (Each Pathway)
- Weight: kg/m
4Gas Pipes
(From the Forward Side)
12 Gas Pipes
20 HV Cables

7. - HV CABLES -
Weight: 0,0162Kg/m
Out diam.: 3.2 mm
L = 50mm

8. - GAS PIPES -
Weight: 0,0162Kg/m
Outer diam: 6 mm

9. - CABLES ROUTING SYSTEM -
- Main aspects and assembling phases.
- A 2° “Cables Support Structure” is inserted and
moved toward the detector.
- The cables and gas-pipes bundles are inserted in
the housings.
- The structure is fixed to the rest.
- B -
- A -
A 1° independent mechanical frame (material can be aluminum) is inserted and connected with the ST Tracker.
Its duty is to support electronics and route cables and other services outside in the backward region.

10. - Side view of STT detector after cables and gas pipes mounting -
- Forward region
- Backward region
103 mm ?
Gas distribution is done in the forward region, then gas pipe have to run along the external surface of the detector to reach gas-manifolds.
- The dimension of 103mm is enough to house the flat cables. We do not yet have the real dimensions of
electronic cards.

11. - CABLES ROUTING SYSTEM -
- Left and right boxes are filled with
signal cables.
Top and bottom space are filled with
HV-cables, gas pipes and other services.
NB: Where the flats bent, their
thickness double.
More in general, the simulation of this
type of situations is too complex to be
exhaustive
A test on a prototype is mandatory.
NB: flat cables need to be fixed inside the routing structure.
Then, additional space for fixing
elements have to be considered.
- The cable routing system is attached to the STT rails.
It drives the cables outside of the PANDA magnet in a tidy way.

12. - Cables routing system: - EMC-BW and DIRC final dimensions.
DIRC Read-Out inner radius: 448mm
(Remain the same)
EMC-BW outer radius: 438mm
(Remain the same)
EMC-BW flat side: 405mm
- EMC-BW: final arrangement:
dimensions in detail.

13. - Cables routing system: First Support Structure.
- Cables Support Structure.
- This mechanical structure will
support the electronics cards
and will direct the cables.
- Straw Modules.
- Support End-Plate.
- HV Distribution.
At present there are 2 cards, but
they can be merged.
- This would be better from the
mechanical point of view
- Read Out Electronics.

14. - Cables routing system: First Support Structure.
- Staggered Flat Cable.
KEL 20 Pairs Connectors.
(Staggered one respect to the other).
There are cutouts in the structure to allow cable passage.
The position of the connectors on the electronic cards should be staggered to have a more uniform thickness of the bunches.

15. - Cables routing system: First Support Structure.
It must be checked that the space for managing the connections of the cables is enough.
The available area for the 43 electronic channels of the second layer, is in this first hypothesis: 174 x 120 (80+40) mm^2.
NB. The final geometry of the electronic cards should be defined!

16. - Straw Tube length definition.
The space available for the Central Tracker (not for the Straw tubes) was established long ago. IP

17. - Space along Z necessary for the First Support Structure in the Backward Region.
We have minimized all the dimensions.
We need ˜160 mm in the backward direction.
The length of the straw in the backward region is
390mm.
- Read Out Electronics.

18. - Space along Z necessary for the First Support Structure in the Forward Region.
We have designed a first solution for the gas distributors supports.
Prototypes are under construction in Torino INFN workshop.
- Juelich gas distributors

19. - Space along Z necessary for the First Support Structure in the Forward Region.
We have minimized all the dimensions.
We need ˜82mm in the forward direction.
The length of the straw in the forward region would be 1018mm. 82
1060mm
- In order not to reduce too much the length of the Straws
we should ask 42mm extra space in the forward region.
- In this way the length of the straw in the forward region
become 1060mm. 32 30 20
1142mm

20. - STRAW TUBE LENGTH PROPOSAL -
The showed layouts allow to have a total length of the Straws: 1450mm ( )
-NB. The final geometry of the electronic cards
should fit the dimensions we presented!

21. - CT SUPPORT BEAM LENGHT-
- Forward Z-coordinate necessary for the Central Tracker rails: 1150
550mm
1142mm
1692mm
- TOTAL LENGHT OF THE «STRAW TRACKER»

22. - SOME ADDITIONAL WARNINGS -
- We want to underline how dense will be the electronics final layout.
- We have to solve how the cabling the outermost “Straw Layers” will
be done once the space is completely filled-up.

23. - FURTHER STEPS -
Cabling options and improvements could be tested on the available prototype once we realize also a
prototype of the cabling support system.
The prototype of the “Straw Tracker Support Structure”, will be shipped to Juelich in the next weeks.