# Presentation: 509598

## Linac Front End Focusing Solenoid R&D Status

- I. Terechkine for the FE meeting

- April 13.2006

## Requirements as of February 16, 2006

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- April 13.2006

## R&D Content

- Choice of a strand and coil winding patterns
- Magnetic modeling (iterative)
- Stress management issues
- Quench protection issues
- Mechanical design
- Test and prototype solenoid program

- I. Terechkine for the FE meeting

- April 13.2006

## Strand R&D

- SSC dipole inner layer NbTi strand:
- 	strand diameter 	 ~ 0.808 mm
- 	filament diameter  ~ 5 mkm
- Modified SSC strand to increase compaction factor
- Oxford rectangular 0.9 x 0.6 mm2 strand
- 	filament diameter ~ 70 mkm
- Round Oxford strands for compensation coils

- I. Terechkine for the FE meeting

- April 13.2006

## Strand R&D

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- April 13.2006

## Magnetic Modeling

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- April 13.2006

## Magnetic Modeling

**Strand Parameters**

**Global Parameters**

**Performance at quench**

- Packing (or compaction) factor:
- K = (S_strand) / S_coil

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- April 13.2006

## Winding Models

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## Stress in Solenoids

- Winding – inevitable strand tension and stress accumulation
- Cooling down to 4 K
- Excitation

**Main Results of study in:**
- Analysis of Stress in PD Front End Solenoids - TD-05-039;
- Test Solenoid Design Proposal – TD-05-040;
- 3.   Review 08-31-05

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- April 13.2006

## Stress in Solenoids

- T = 300 K  I = 0 A

- T = 4 K
- I = 0 A

- T = 4 K
- I = 300 A

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- April 13.2006

## Stress in Solenoids

**Hoop Stress After Winding - Pa**

**Hoop Stress After Cooling down – Pa**

**Hoop Stress After Energizing - Pa**

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- April 13.2006

## Quench Protection 

- Quench Propagation and Maximal Temperature
- Quench heaters:
- 	-- do we need it?
- 	-- can we make it?

**Main Results of study in:**
- 1. Focusing Solenoid Quench Protection Studies.
- Part I: Method Description and the First Iteration. 	TD-06-003
- 2. Focusing Solenoid Quench Protection Studies.
- Part II: Test Solenoid Quench Protection. 		TD-06-004
- 3. Solenoid Quench Heater			TD-06-006
- 4. Review 12-02-2005

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- April 13.2006

## Quench Propagation

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## Quench Propagation

**a) I = 200 A; t = 3.5 ms, 90 ms, 220 ms**

**b) I = 250 A, t = 2 ms, 70 ms, 120 ms**

**c) I = 330 A, t = 0.3 ms, 12.5 ms, 44 ms**

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- April 13.2006

## Coil Heating

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## Quench Heater

- a) tins = 50 μm		b) tins = 100 μm		c) tins = 200 μm

- Quench delay as a function of insulation thickness

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- April 13.2006

## Test Solenoid

- Expected Quench Current – 306.8 A
- Central Field at quench current – 7.1 T
- Maximal Field in the Coil – 7.5 T

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- April 13.2006

## Stress

- Gauge - VISHEY, Micro-Measurement Group, WK-09-250BG-350/W

- Gauge Calibration

- Gauge readings during cooling down

- Stress during excitation

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- April 13.2006

## Magnetic Field

- Measured and Calculated Field Profiles w/o Flux Return

- Field distribution with and w/o core

- Measured and Calculated Field Profiles with the Flux Return

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## Heater Test

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## Coil Quench Behavior 

- Quench current is within 1% from the prediction

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## Hysteresis in the magnetic behavior

- Measured hysteretic behavior was measured as a residual magnetic field at I = 0. The value of the residual field  reaches + / - 16 Gs and almost does not depend on the excitation current.
- Magnetic core can be excused for only 0.5 Gs
- So, most probably, we see hysteresis in the strand.
- Some modeling work must be performed to explain the effect.
- Some anomalies in the current supply behavior (non-zero current at zero setting) must be addressed to allow precision measurements.

- I. Terechkine for the FE meeting

- April 13.2006

## Conclusion

- The three test solenoids will provide information to allow strand choice for the main coil
- The test solenoid behaves as predicted; this allow more subtle features to be investigated, e.g, hysteresis and coil fabrication precision
- Prototype cold mass for the CH section focusing solenoid will address issues associated with the compensation coils
- 	Pre-release review was held on April 06

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- April 13.2006

## Solenoid for the CH-type accelerating module

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- April 13.2006

## Plan of Actions

- PDST-02 fabrication - ongoing
- PDST-02 testing – April 17 – 28
- PDST-03 fabrication - April 17 – 28
- PDST-03 testing – May 01 – 12
- PDSCH-01 drawing release – ongoing
- PDSCH-01 fabrication – May – July
- PDSCH-01 testing – August
- Design of the cold mass for S/C section can start in May. Allow ~ 3 month to prepare for a pre-release review.

- I. Terechkine for the FE meeting

- April 13.2006