1. IMP Cryomodule Assembly and Alignment
Hao Guo
LINAC Department
Institute of Modern Physics
Good morning, everyone! I will introduce the strings assembly of superconductor cavity.

2. Cryomodule components-CM6
6 HWR,
6 tuner,
6 coupler,
6 SC solenoid,
5 BPM.
Thermal radiation shield
Aluminum plate and Muti-layer insulation
80K LN2 cooling
insulating vacuum: 10-4Pa
Clean room assembly
- dimension: 4.2m×1.2m×1.6m
- beamline vacuum: 10-7Pa
11/28/2018
IMP

3. Fixture for strings assembly
This is the second vision of strings fixture. The main advantage of this fixture is that it could be divided into six parts. Each parts could support on cavity, on solenoid and one coupler.
The second vision of CM6 strings fixture.
This fixture could be divided into six parts, and each parts could support one cavity, one solenoid and one coupler.

4. Fixture for strings assembly
The second vision of CM6 strings fixture

5. Assembly environment Class 100 clean room Length: 6m Width: 3m
Width of the door: 2m
Assembly operators: 4 persons

6. Assembly procedure Put parts on assembly fixture
Blow screws, bolts, nuts, washer , gasket or flange with high purity nitrogen
Tight all screws to 30Nm
Pre-alignment
Connect parts by bolts without fastening
This is our assembly procedure. First we put the parts on assembly fixture, than blow the fasteners by nitrogen. After that we adjust the position of the parts, remove plastic film and connect parts. At last we tight all bolts and screws to 30Nm

7. The counter of particles less than 40 per minutes
Assembly procedure
The final test of every assemblies without SC cavities before strings assembly
Leak check
cleanliness
Less than
5E-10mbarL/s
The counter of particles less than 40 per minutes
Before the strings assembly, we had a final test of every parts about leak check and cleanliness.

8. Challenges for cleaning RF components
Welded bellows: the particles will hide in bellows and hard to remove.
BPM: the particles will hide in buttons and hard to remove. (assembled and calibration in unclean room)
couplers: the particles will hide inside and hard to remove. (Power condition in unclean room)
The particle counter of bellows and BPM cleaned by ultrasonic (0.3μm)
bellows
BPM
coupler
>300 per 10s
>10000per 10s
>400 per 10s
The main change of structure, we add a needle bearing to let the solenoid could sliding at a certain range. It could let us assemble easier between cavity and solenoid and it easier to protect the cleanliness.

9. Challenges for cleaning RF components
Test area
Solution: assembled in cleanroom and cleaned by HPR
Parameter of HPR and particle counter (0.3μm)
parts
bellows
BPM
Coupler
Pressure
60bar
40bar
Rotate speed
20rpm
Rinsing time
8min
15min
22min for outer conductor,
5min for inner conductor
Without clean
>12000 per 10s
Ultrasonic clean
>300 per 10s
>17000 per 10s
>400 per 10 s
HPR
0 per 10s
>900 per 10s
N2 blow area
The main change of structure, we add a needle bearing to let the solenoid could sliding at a certain range. It could let us assemble easier between cavity and solenoid and it easier to protect the cleanliness.
Particle counter of BPM after ultrasonic cleaning and drying

10. Improvement for cleaning RF components
We have done already
HPR for bellows
HPR for solenoids
We plan to do
The main change of structure, we add a needle bearing to let the solenoid could sliding at a certain range. It could let us assemble easier between cavity and solenoid and it easier to protect the cleanliness.
HPR for BPM
HPR for coupler

11. Pre-alignment in cleanroom
The purpose of pre-alignment in cleanroom
To prevent the abnormal twist of bellow in the cryomodule assembly.
At this I will show the sequence of strings assembly. At first step, we join every cavity, solenoid and coupler. Then we adjust level of cavity and solenoid. At last, we tight bolts.

12. Fixture for strings assembly
The detail structure of solenoids supporter
Needle bearing
The main change of structure, we add a needle bearing to let the solenoid could sliding at a certain range. It could let us assemble easier between cavity and solenoid and it easier to protect the cleanliness.
功能描述
The solenoid supporters could adjust the position of solenoid.

13. Pre-alignment in cleanroom
First step: join the flanges of cavity and solenoid then fix screws without fastening.
Second step: adjust levelness of cavity and solenoid by frame level meter.
Third step: fasten screws to 30Nm
At this I will show the sequence of strings assembly. At first step, we join every cavity, solenoid and coupler. Then we adjust level of cavity and solenoid. At last, we tight bolts.

14. The improvement for strings assembly
All parts could slide on linear guide
The structure of supporter have be designed to adjust parts easier.
12 bolts could be used for adjusting the position of every parts.
The main change of structure, we add a needle bearing to let the solenoid could sliding at a certain range. It could let us assemble easier between cavity and solenoid and it easier to protect the cleanliness.
功能描述

15. Low speed vacuum
The vacuum pumping rate is limited by mass flowmeter. The rate is 0.1 slm.
Mass flow meter for vacuum pumping
Mass flow meter for venting N2
The last step, we vacuum the strings and the vacuum pumping rate is limited by mass flowmeter. The rate is 0.1 standard liter per minutes. For our strings, we need 30 hours for vacuum. I had a questions about vacuum leak. If we found the strings is leak, how to solve it? Is that necessary to disassemble all the parts, clean and assemble again.
Question: If the vacuum of strings leak, how to solve it?

16. Alignment process chart
Single component’s calibration
Bundle calibration
BPM+Solenoid
Location and measurement
of offline network
Offline alignment and monitoring
Online alignment

17. Offline alignment and monitoring
Portable CMM and Laser Tracker are cooperative used
The least alignment time only used laser tracker is about 1-2 weeks;
The cooperative alignment time is reduced to 1-2 days

18. Displacement and deformation of 78K
Transverse
Vertical
Measure range±1.2mm

19. summary
TCM6 passed the beam of 4mA 5Mev CW. So the entire process of cryomodule process is feasible. But the detail should been improved.
The improved cleaning process of BPM and coupler could been testing on next cryomodule.
The measure range of offline alignment is ±1.2mm.

20. Thanks for your attention!