Minutes of ILD MDI/Integration WG meeting, 15 July, 2008

1. Progress report of ILD2

status at DESY by K. Buesser

ANSYS calculation of iron structure performance is being prepared at DESY. Major issues are an opening method of endcap yokes and rigid structure for push-pull scheme. Also, the tail catcher structure will be considered in the iron yokes, since CALICE group expressed its necessity, i.e. 5 or 6 absorption length of calorimeter thickness is not enough for the performance. The tail catcher should have 5 layers interleaved with 10cm thick iron plates. It might be problematic in the end cap for strength against magnetic force, while the barrel yokes could implement it.

Symmetry of yokes is also studied, since the tail catcher prefers the same symmetry, i.e. 8 or 12 fold, as calorimeters.

A rigid outer frame must be necessary without platform at push pull, since the detector consists of 3 barrel rings and 2 endcap rings for "weakness" against external force. DESY will design the frame.

There were questions on the tail catcher and the outer frame for "physics" motivation and necessity, respectively. It was commented that M.Thompton's studies showed that 5 or 6 absorption length was enough for PFA in calorimeters, so no tail catcher would be needed.

At next meeting, 2 weeks from now, some results of iron structure will be presented.

status at LLR by C. Clerc

Stray field has been studied in ILD2, at B=4T. It turned out that total thickness of iron should be 7m at least in order to satisfy the condition, that is, the maximum stray field must be less than 200 Gauss at 10 m in Z and yoke outer radius plus 50 cm. Also, we need to close gaps in the 5 rings.

A square hole in the endcap is expected to have the same "magnetic" performance as a circle one. It will be calculated.

Updated iron structure of GLDc will be uploaded to a web site, whose URL will be informed (Y.Sugimoto).

status at LAL by M.Jore

3D-CAD drawings of latest forward region was showed. The square support tube was visible and it was very interesting. Strength of this tube will be studied.

There were questions on alignment system of QD0 and dynamic range of position adjustment of the tube.
In the IR interface document (draft), which has been submitted as a contributed paper at EPAC08, it is expressed that "The QD0 cryostat would have its own alignment system of the ±2mm range for fine alignment" and "the detector would provide to machine the means to know the vertex position and also provide four channels for an optical path to each of the QD0 cryostats, to perform interferometer triangulation from underneath of the detector" .

2. Progress report of ILD1 by T. Tauchi

We (H.Yamaoka) will study a cylindrical support tube for forward calorimeters and QD0. Also, we will study a 3D field performance of anti-DID in GLD. The anti-DID field has never been estimated with iron yokes.

At KEK, we discussed on questions to sub-detectors in order to prepare information for the integration. Preliminary questions are listed below;

All sub-detectors
- overall sizes, especially outer and inner diameters and total length
- total cross section of cables and pipes (gas and cooling material) and the maximum diameter among them in order to determine gaps between sub-detectors for them
- support method/mechanism
- alignment method, e.g. laser system- how to inject a laser beam, where the laser system is installed etc.
- total weight
- total electric power consumption
VTX and SIT
- inner support tube inside of TPC is needed ?
  e.g. SIT and vacuum pipe are supported by the tube and VTX is mounted on the beam pipe. The tube is supported by TPC.
TPC
- how much is the field uniformity ?
  - a LCTPC note will be available soon. It may discuss ;
  - field reproducibility during push pull
  - anti-DID field is not constant, i.e. it will be varied during experiments
  - requires precise field measurement and calibration at Z-pole
ECAL, HCAL
- 8 or 12 fold symmetrical shape
  -A documentation will be prepared by T.Taheshita, which summaries advantages and disadvantages in each shape.
HCAL
- module shape ? - conventional or Henri's one
- need tail catchers behind the coil and in the endcap ?
COIL
- sizes of cryostat, chimney and anti-DID coil
Anti-solenoid for permanent QD0 (option)
- It will be buried in the endcap yoke. Y.Iwashita will study it.
MUON
- need a contact person
- especially number of layers are important and urgent to be decided.

It was suggested to distribute these questions to sub-detector contact persons as soon as possible for efficient discussion at the ILD Cambridge meeting.