## SMTF collaboration meeting at Fermilab, 5 -- 7 October 2005 

## Working group 2 (modules) notes and comments 

Attendees (in alphabetical order):

Tug Arkan (<arkan@fnal.gov> ), Harry Carter (<hfcarter@fnal.gov> ),
Helen Edwards (<hedwards@fnal.gov> ), Kay Jensch (<kay.Jensch@desy.de>
), Rolf Lange (<rolf.lange@desy.de> ), Don Mitchell (<dmitchel@fnal.gov>
), Tom Nicol (<tnicol@fnal.gov>), Norihito Ohuchi
(<norihito.ohuchi@kek.jp> ), Carlo Pagani (via video link from Milan,
<carlo.pagani@desy.de>), Nicola Panzeri (<nicola.panzeri@mi.infn.it>),
Paolo Perini (<paolo.pierini@mi.infn.it>), Tom Peterson
(<tommy@fnal.gov>), Claus Rode (<rode@jlab.org>), F. Scuri (via video
link from Pisa), Nobu Toge (<nobu.toge@kek.jp> ), John Weisend
(<weisend@slac.stanford.edu>)

Following the plenary talks on Wednesday morning, 5 October, Working
Group 2 (WG2) met for two full days up to the Friday afternoon close-out
session.

The major WG2 discussion topics were:

1.  Module features and design issues, pros and cons of various options

2.  "Type 3+" (currently being fabricated) versus "type 4" (next design
    iteration) versus longer term for ILC

3.  Levels of effort and time scales for design efforts

Formal talks within the WG2 meetings included:

Current Cryomodules and Changes for ILC \-- Carlo Pagani

Cryomodule Controls Inside \-- F. Scuri (Pisa, via video)

Quad Support Alternatives \-- Don Mitchell

Cryomodule Cost Reduction \-- Rolf Lange

SMTF Collaboration Modules \-- Helen Edwards

Proposal of the Linac Quadrupole \-- Norihito Ohuchi

Talks may be found at the SMTF Collaboration Meeting website:
[http://ilc-dms.fnal.gov/Workgroups/SMTF/Collaboration%20Meetings/SMTF%20Collaboration%20Meeting%20Oct%205%2C6%2C7%202005/](http://ilc-dms.fnal.gov/Workgroups/SMTF/Collaboration Meetings/SMTF Collaboration Meeting Oct 5%2C6%2C7 2005/)

Two tables were generated during the meetings. The first is a summary of
major design issues and concerns for the ILC prototype modules. This
table is similar to that generated a year ago in Working Group 5 of the
ILC-Americas workshop

(<http://www-project.slac.stanford.edu/ilc/meetings/workshops/US-ILCWorkshop/wg5.html>)

We have incorporated comments from recent talks by various people,
particularly Carlo Pagani and Helen Edwards.

The second table summarizes the group's consensus about the time scales
and level of effort involved for the upcoming prototype modules. The
bottom line is that a next generation (Type 4) module, after the Type 3+
currently being fabricated, is about a three-year effort from design
through testing.

+-------------------------------------+-------------+-----------------+
| Major cryomodule design issues,     | Near term   | ## Acti         |
| concerns                            | for **Type  | on or solution  |
|                                     | 4** design  |                 |
|                                     | or **longer |                 |
|                                     | term for    |                 |
|                                     | ILC**       |                 |
+-------------------------------------+-------------+-----------------+
| 1.  General issues                  | "Type 4" is | Building first  |
|                                     | viewed as   | prototype       |
|     a.  Need to gain assembly and   | the next    | modules must    |
|         test experience within the  | prototype   | remain top      |
|         collaborating labs          | design      | priority, but   |
|                                     | after those | need to         |
|     b.  Also need to start work     | modules     | identify people |
|         toward ILC module           | currently   | to work on      |
|         design; (a) above competes  | being       | longer-term     |
|         for resources but feeds     | ma          | design effort.  |
|         into design.                | nufactured. | Need regional   |
|                                     | Production  | contact person  |
|     c.  Need specifications for     | and tests   | to get and      |
|         type 4                      | of multiple | distribute      |
|                                     | Type 4's    | info.           |
|     d.  Particularly need design    | could lead  |                 |
|         specifications for          | to an ILC   |                 |
|         quad-steerer package with   | module      |                 |
|         respect to centering,       | design.     |                 |
|         hysteresis, etc.            |             |                 |
+-------------------------------------+-------------+-----------------+
| 2.  Maximize packing factor, closer | Type 4      | With (3) below, |
|     cavity spacing, improve "real   |             | this is a major |
|     estate gradient"                |             | part of the     |
|                                     |             | Type 4 effort.  |
|     a.  Coaxial tuner               |             |                 |
|                                     |             |                 |
|     b.  Revise intercavity flange   |             |                 |
|         design                      |             |                 |
+-------------------------------------+-------------+-----------------+
| 3.  Alignment and positional        | Type 4:     | This issue      |
|     stability                       | Address     | should be the   |
|                                     | these       | focus of        |
|     a.  Need requirements           | issues and  | changes in the  |
|                                     | measure     | type 4 module.  |
|     b.  Measurement and             | results in  |                 |
|         verification of positions   | type 4,     |                 |
|                                     | then        |                 |
|     c.  Position of quadrupole      | further     |                 |
|         (center, end, separate).    | design      |                 |
|         Center is preferred basis   | refinements |                 |
|         for Type 4.                 | follow      |                 |
|                                     |             |                 |
|     d.  Integration of BPM with     |             |                 |
|         quad                        |             |                 |
|                                     |             |                 |
|     e.  Stability with shipping     |             |                 |
|                                     |             |                 |
|     f.  Stability with thermal      |             |                 |
|         cycles                      |             |                 |
|                                     |             |                 |
|     g.  Vibrations                  |             |                 |
+-------------------------------------+-------------+-----------------+
| 4.  In any solution need            | Type 4      |                 |
|     quad-BPM-steerer package        |             |                 |
|     integration, including          |             |                 |
|     clean-room compatibility, an    |             |                 |
|     important engineering effort.   |             |                 |
|     Would like to see real BPM in   |             |                 |
|     type 3+.                        |             |                 |
+-------------------------------------+-------------+-----------------+
|                                     |             |                 |
+-------------------------------------+-------------+-----------------+
| 5.  Active remote "movers" for quad | Longer term |                 |
|     alignment                       |             |                 |
+-------------------------------------+-------------+-----------------+
| 6.  Reliability                     | Longer term | Reliability     |
|                                     |             | issues are      |
|     a.  Vacuum feedthroughs         |             | always part of  |
|                                     |             | the design      |
|     b.  Tuner (fast and slow)       |             | consideration   |
|                                     |             | but need test   |
|                                     |             | results         |
+-------------------------------------+-------------+-----------------+
| 7.  Assembly                        | Longer term | An old          |
|                                     |             | engineering     |
|     a.  Industrialization           |             | "rule of        |
|                                     |             | thumb":         |
|     b.  Cost reduction              |             | increase        |
|                                     |             | production runs |
|         i.  Labor (60 -- 80         |             | in factors of   |
|             man-days now per module |             | ten -- one      |
|             at DESY)                |             | prototype, then |
|                                     |             | 10 of next      |
|         ii. Materials               |             | generation,     |
|                                     |             | then 100 of     |
|         iii. Designs, e.g., flanges |             | next, etc.      |
+-------------------------------------+-------------+-----------------+

+---------------+----------------------------+---------+--------------+
| **SMTF        |                            |         |              |
| Collaboration |                            |         |              |
| Meeting --    |                            |         |              |
| Working Group |                            |         |              |
| 2 --          |                            |         |              |
| Cryomodules** |                            |         |              |
|               |                            |         |              |
| # Current a   |                            |         |              |
| nd near term  |                            |         |              |
| tasks and lev |                            |         |              |
| els of effort |                            |         |              |
+---------------+----------------------------+---------+--------------+
| **Task**      | **Concerns or issues**     | *       | **How long   |
|               |                            | *FTEs** | (months)**   |
+---------------+----------------------------+---------+--------------+
| Prepare for   | -   "Americanization" of   | 4       | 6            |
| fabrication   |     DESY and INFN drawings |         |              |
| of 2 TTF      |                            |         | (4 remain)   |
| generation 3  | -   Fill in design details |         |              |
| cryomodules   |     as necessary           |         |              |
| at Fermilab   |                            |         |              |
+---------------+----------------------------+---------+--------------+
| Fabricate 2   | -   Fabrication oversight  | 8       | 18           |
| TTF           |                            |         |              |
| generation 3  | -   Address issues as they |         |              |
| cryomodules   |     arise                  |         |              |
| (1 "kit" from |                            |         |              |
| DESY, 1       |                            |         |              |
| local)        |                            |         |              |
+---------------+----------------------------+---------+--------------+
| Test          | -                          | 4       | 8            |
| generation 3  |                            |         |              |
| cryomodules   |                            |         |              |
| at SMTF       |                            |         |              |
+---------------+----------------------------+---------+--------------+
| Develop TTF   | -   Design requirements    | 10      | 24           |
| generation 4  |                            | (F      |              |
| cryomodule    | -   Quad position and      | ermilab | 24           |
| design        |     configuration          |         |              |
|               |                            | and     |              |
|               | -   Improve alignment      | INFN)   |              |
|               |     mechanics              |         |              |
|               |                            | 10      |              |
|               | -   Vibration inputs and   |         |              |
|               |     response               | (KEK)   |              |
|               |                            |         |              |
|               | -   Incorporate coaxial    |         |              |
|               |     tuner                  |         |              |
|               |                            |         |              |
|               | -   Reduce                 |         |              |
|               |     cavity-to-cavity       |         |              |
|               |     spacing                |         |              |
|               |                            |         |              |
|               | -   Reduce                 |         |              |
|               |     module-to-module       |         |              |
|               |     spacing                |         |              |
|               |                            |         |              |
|               | -   Determine optimal      |         |              |
|               |     number of cavities per |         |              |
|               |     cryomodule             |         |              |
|               |                            |         |              |
|               | -   Incorporate shipping   |         |              |
|               |     concerns               |         |              |
|               |                            |         |              |
|               | -   Reliability            |         |              |
|               |                            |         |              |
|               | -   Cost reduction         |         |              |
|               |                            |         |              |
|               | -                          |         |              |
+---------------+----------------------------+---------+--------------+
| Design and    | -                          | 2       | 18           |
| develop       |                            |         |              |
| magnet        |                            |         |              |
| package       |                            |         |              |
+---------------+----------------------------+---------+--------------+
| Fabricate 2   | -   Fabrication oversight  | 8       | 6            |
| generation 4  |                            |         |              |
| cryomodules   | -   Address issues as they |         |              |
|               |     arise                  |         |              |
+---------------+----------------------------+---------+--------------+
| Test          | -                          | 4       | 8            |
| generation 4  |                            |         |              |
| cryomodules   |                            |         |              |
| at SMTF       |                            |         |              |
+---------------+----------------------------+---------+--------------+
| **Total**     | -   **Bottom line here is  | **50**  | **3 years**  |
|               |     that assembly and test |         |              |
|               |     of the current type 3+ |         |              |
|               |     modules will be a two  |         |              |
|               |     year effort, in        |         |              |
|               |     parallel with the type |         |              |
|               |     4 design effort.       |         |              |
|               |     Fabrication and test   |         |              |
|               |     of type 4 then follows |         |              |
|               |     type 3+ with           |         |              |
|               |     completion of tests 3  |         |              |
|               |     years from now.**      |         |              |
+---------------+----------------------------+---------+--------------+

Quad/steerer/BPM package position discussion.

Implementation of steering/quad integration can be concentric package,
separate packages, or quad active positioning. *Listed in order of
current preference as guidance to designers who will do Type 4 design
effort.* Comment: in any solution need quad-BPM-steerer package
integration, including clean-room compatibility, an important
engineering effort. Would like to see real BPM in type 3+.

1\. Center on 300 mm pipe:

Pro: we know how to do this, similar to cavity supports, most stable
part of module in being far from interconnect forces and at the fixed
post

Con: harder to do movers, center of vacuum vessel not directly supported

Give first priority effort to #1. The others below are options for some
study and further consideration.

2\. End on 300 mm pipe with generation 3 post location:

Pro: we know how to do this, similar to cavity supports

Con: interconnect pipe forces may affect quad position

3\. End on separate support:

Pro: more positive positioning, easier to implement movers,

Con: different thermally-induced movement from cavities, increased heat
load (0.2 W, 0.8 W, 10 W heat load static per post, out of 3 W at 2 K
per module), interconnect pipe forces may affect quad position

4\. Center on separate support:

Pro: more positive positioning, easier to implement movers,

Con: difficult assembly, difficult alignment, different
thermally-induced movement from cavities, increased heat load (0.2 W,
0.8 W, 10 W heat load static per post, out of 3 W at 2 K per module)

5\. Separate quad cryostat:

Pro: all the modules the same, quad not connected to gas return line

Con: most difficult to leak check, extra interconnect (cost and
reliability), difficult outer vacuum bellows, most subject to external
interconnect forces, significant design effort

## Summary, conclusions, general remarks 

Building first prototype modules must remain top priority. We need to
gain the experience. But we need to make progress toward a Type 4
design, and to that end we should identify people to work on longer-term
design effort.

For Type 4 we agree: quad location centered on 300 mm pipe

Pro: we know how to do this, similar to cavity supports, most stable
part of module in being far from interconnect forces and at the fixed
post. It is the next logical evolution of the present TTF design.

Con: harder to do movers, center of vacuum vessel not directly supported

In any solution one needs quad-BPM-steerer package integration,
including clean-room compatibility, an important engineering effort.
Would like to see real BPM in type 3+ (including upcoming DESY module)

TESLA Technology Collaboration (TTC) topics:

1.  Update this document (or create a similar document) defining the
    baseline ILC cryomodule design. A summary document should include
    some "generation 4" module alternative concept illustrations but
    make clear what is BCD, RDR, or optional for future. We are working
    toward a Baseline Configuration Document -- Dec 2005 \-- and
    Reference Design Report -- Dec 2006 -- as well as ILC R&D.

2.  Begin listing questions, items to be measured, for a module test
    program. Work should start soon on a module test stand, end boxes,
    etc.