# Presentation: 669269

## IR Quad Design Study Summary 

**IR Quad Design Study Summary **
**& Open Issues **
**Vadim Kashikhin**
**October 19-21, 2004**

**LARP Meeting**

***bnl - fnal- lbnl - slac***

_**US LHC Accelerator Research Program**_

## R&D questions

**We studied different designs of Nb****3****Sn quadrupoles to address the following questions:**
**What are the aperture limitations for the single and double bore configurations?**
**What are other limiting factors?**
**What field quality can be achieved?**
**What are the possible coil/yoke designs?**
**What are the operation margins?**
**What are the conductor requirements?**

**R&D questions**

## Single-bore shell type magnets

**The aperture limitations were studied for the shell type IRQ with J**c**(12T,4.2K) ~3kA/mm****2 ****and B****peak****~15T.**
**Shell type magnets with 90-110 mm apertures meet our goals for the maximum gradient and field quality.**
**The 100-110-mm aperture is the upper limit for a magnet with the nominal gradient of 205 T/m and 20% quench margin.**
**The 90-100-mm designs can employ 2-3-4 layer coils, and the 110 mm design require 3-4 layer coils.**

## Single-bore racetrack type magnets

**The racetrack designs with closed and open midplanes were studied and compared with the equivalent shell type magnets.**
**The racetrack quadrupoles are less effective than the shell type designs with the equivalent apertures by all the major parameters, including gradient, field quality, coil volume, etc.**
**Due to the coil size limitations, the racetrack design is not appropriate for the 2-in-1 configuration.**

## Double-bore magnets

**The 2-in-1 quadrupole limitations were studied from the geometrical and field quality viewpoint.**
**The 2-in-1 quadrupole can accommodate a maximum bore of ~100 mm for the beam separation distance of 194 mm.**
**Asymmetric coils with a warm or cold iron yokes control the geometrical field quality and the yoke saturation effect.**
**The warm yoke design has smaller cryostat size, but the cold mass should be precisely centered within the yoke. The cold yoke design has smaller coil asymmetry and is not affected by the eccentricity forces.**

## Thermal margin and

**quench protection **

**The Nb****3****Sn magnet designed with 20% quench margin can withstand ~40 mW/cm****3**** of peak power dissipation in the midplane turns at T****op****=1.95K.**
**The 90-100 mm magnets can be protected with the quench heaters.**

## Design study for the short 

**quadrupole model **

**Constrains:**
** ****90-mm aperture;**
** ****Maximum use of the existing tooling and technology:**
**   ****- Bladder and key design (LBNL);**
**   ****- MQXB collars and iron yoke (FNAL).**

## 4-layer quadrupole for the bladder 

**and key mechanical structure**

## 2-layer quadrupole for the MQXB

**mechanical structure**

## 3-layer quadrupole for the MQXB

**3-layer quadrupole for the MQXB**
**mechanical structure**

## 3D magnetic analysis of the 

**90-mm IRQ in MQXB structure**

**Optimized coil ends – peak field is in the straight section.**
**Integral field optimization will be done for the 1-wedge design.**

## Open issues & questions for FY05

**Determine ranges for the nominal gradient, aperture and magnet length based on the possible IR designs (for the single-bore case).**
**Development of the first version of the field error tables (using statistics from 4-6 W&R Nb****3****Sn magnets).**
**Analysis of the Nb****3****Sn model magnet R&D data (conductor, mechanics, quench protection and flux jump studies) in order to find the magnet design limitations.**