# Presentation: 320558

## LER Magnets Major R&D Effort

- The new injection scheme shows only
- the path from SPS to LER to LHC

- There are 2 distinct sets of magnets:
- Arc magnets covering ~ 26 km of
-         accelerator circumference
- LER to LHC transfer line magnets
-         covering total of ~ 1 km of beam
-         path
- The VLHC low field magnet is proposed
- as the base magnet for the LER arc.
- The LER-LHC transfer line magnets are
- viewed as new initiative in magnet design.

- A. Zlobin

- 2/24/98

## VLHC & LER Magnet Count  

**VLHC:**
**             **
**         ****- 233 km accelerator ring**
**         ****- ~ 3200 main arc dipoles**
**         ****- ~ 466 km continued length**
**              ****of transmission line**
**              ****superconductor**
**LER:**
**      **
**          ****- ~27 km accelerator ring**
**          ****- 1232 main arc dipoles**
**          ****- ~ 54 km continued length**
**             ****of transmission line**
**            ****superconductor**

- A. Zlobin

- 2/24/98

## Base Magnet of the LER Accelerator

**  ****LER Main Arc Dipole Magnet**
**  **
** ****Magnet cross-section area:**
**   ****26 cm (height) x 24 cm (width)**
**   ****Pole gap: 20 mm (?)**
** ****1.6 Tesla field (nominal operation)**
**   ****(****1.99 T for VLHC)**
** ****0.6 Tesla  (beam injection)**
**   ****(****0.2 T for VLHC)**
** ****Alternating gradient: 12 m (****64 m****)**
** ****20 mm magnet pole gap ( 25 mm ??)**
** ****Energized by 55 kA (****87 kA for VLHC)****,   **
**  ****single turn superconductor line**
** ****Coolant – supercritical helium  **
**  ****(4.2 K, 3 bar, 60 g/s) **
** ****Warm beam pipe vacuum system-**
**  ****ante-chambers required**

**We propose that LER is based on the**
**VLHC low field, combined function dipole magnet**

- A. Zlobin

- 2/24/98

## LER Magnet Location in the LHC Tunnel

** ****It fits easily in the space above the**
**  ****LHC magnet**
**Vertical distance between LHC and **
**  ****LER beams: 1350 mm**
**The holding brackets and the magnets**
** ****can be installed without disturbing the**
** ****LHC operations**
**The 4 K, 3 bar LHe can be tapped at **
** ****convenient locations from the QRL line  **
** ****providing 1700 g/s flow**

- A. Zlobin

- 2/24/98

## LER Arc Dipole Magnet in LHC Tunnel

**Normal tunnel area**

**Area with cryogenic feed tower**

- A. Zlobin

- 2/24/98

## VLHC Magnet and B-field Measuring Instrumentation

**Magnet view (tangential coil side)**

**Magnet view (Hall station side)**

- A. Zlobin

- 2/24/98

## Magnetic Measurements

***Gueorgui Velev, TUA07PO02***

**Probe: 15.2 mm dia. x 754.1 mm long**
**Vespel (polyimide) used to form the probe (winding support) and bearings.**
**Field Harmonics measured to:**
**order 10 at 1.966 Tesla ****(collisions)****,**
**and order 6 at 0.1 Tesla ****(injection)**
** **

- A. Zlobin

- 2/24/98

## Magnetic Measurements

**Quadrupole component is as designed; ~ -415 units, both at**
**injection and full field 1.966 T.**
**102 element Hall Probe confirms**
**the +/- 4% gradient.**
**Sextupole component very small;**
**~ few units, and no change from**
**injection to the full field 1.966 T.**
**The b4 – b10, and the a4 – a10**
** ****also  << 4 units,  or << 0.04%. **
**LER magnet operates at 1.6 T !!**

- A. Zlobin

- 2/24/98

## Principle of the LER-LHC Beam Transfer 

**After the LER ring filling is complete, the pulsing magnets are turned **
**off as soon as the last proton bunch passed through them. **

- A. Zlobin

- 2/24/98

## Principle of LER-LHC beam transfer

**Cryogenic support for fast pulsing magnets must sustain long-term**
**operations at 0.45 TeV, and a 100 second long ramping to 1.5 TeV**

- A. Zlobin

- 2/24/98

## LER-LHC Transfer Line Boundaries

**Total length of 1⁄2 straight section: 260 m**
**Available free space between D1 and Q7: 176.5 m **
**To reproduce the LHC optics the LER-LHC transfer line magnets must reach the LER level of 1100 mm at the D2 LHC dipole (approximately 65 m from the end-face of D1)**
**A 336 T-m bending power is required to lift a 1.5 TeV beam by 1100 mm above the LHC nominal beam level, or  on average ~5 T magnets are required for a 65 m beam path**
**For comparison, to bypass detectors by ~ 40 m in the straight sections of 260 m the transfer line magnets of ~50 T field would be needed**

- A. Zlobin

- 2/24/98

## LER-LHC Transfer Line Option 1

**No re-arrangement**
**of LHC, D1 magnet.**
**4 vertical bends**
**preceded by a **
**horizontal bend to**
**provide enough  **
**separation in the**
**first pair of vertical **
**dipole magnets for**
**the “cc” and “cw” **
**LER beams.**
**Three sets of fast **
**pulsing magnets are **
**needed!**

- A. Zlobin

- 2/24/98

## LER-LHC Transfer Line Option 2

**LHC D1 magnet is**
**moved a bit (or **
**shortened) to make **
**a space for a  (5 m?) **
**LER single bore **
**dipole magnet.**
**Only one set of fast**
**Pulsing magnets is**
**needed!**** **

- A. Zlobin

- 2/24/98

## An Example of  Possible Vertical Bend Magnet Arrangement 

- A. Zlobin

- 2/24/98

## LER-LHC Transfer Line Magnets

**     ****In order to accomplish the LER-LHC beam transfer the beam  **
**     ****line must consists primarily of three type of dipole magnets:**
**            ****- 2 T range, normal conducting, fast pulsing, single bore dipole to**
**              ****enforce the LER beam circulation in the LHC**
**            ****- 2 T range, normal conducting, single bore dipole operating with **
**              ****the LHC LER beam pipe separation of no less than 75 mm **
**             ****(40 mm beam pipe and ~ 30 mm for the magnet yoke)**
**            ****- 7-8 T, superconducting, two-bore, 1m long vertical dipole to pass**
**              ****the LER beam through most of the 1.35 m vertical separation**

- A. Zlobin

- 2/24/98

## Fast Pulsing Magnets

**- For 3 microseconds current decay time, L < 1 uH, so the magnet length is  **
**  ****typically < 1 m, and the conductor spacing 40-60 mm.**
**- For B field in 2 T range, the conductor current is in the range of 100 kA.**
**- ****Magnet operating < 25 K (lowest resistance of Cu) is the only option.**

- From Martin N. Wilson,
- Superconducting Magnets,
- ISBN 0 19 854810 9 (Pbk), 1997

- A. Zlobin

- 2/24/98

## Fast Pulsing LER-LHC Transfer Line Magnets

- Horizontal bend of both LER beams.               Vertical bend of the LER beams,
- B-field shaped by laminations,                         B-field shaped by conductors,
- conductors are LHe cooled.                              conductors are LHe cooled.

- 40 mm gap, 1.5 T max @ 90 kA
- Pulsed or continual operation

- 60 mm gap, 2.0 T  max @ 67 kA pulsed or continual operation. CERN operated WC 0.6 T magnet @ 29 kA

- A. Zlobin

- 2/24/98

## LER-LHC Transfer Line Magnets  

**A vertically bending magnet –**
**for horizontally separated LER**
**and LHC beams.**
**Continual or fast pulsing  **
**operations. **
**Laminations are used to contain **
**magnetic flux, and to minimize **
**fringe field at the LHC beam. **

- A. Zlobin

- 2/24/98

## Fast Pulsing Magnet Power Supply

**  **For I = 90 kA and L =1 uH of the magnet system, the voltage drop is 30 kV at
-   3 microsecond of current decay time. Lowering the operating temperature of
-   the power supply switcher cells to 25 K will eliminate need for the HTS leads.

- A. Zlobin

- 2/24/98

## LER Major Magnet R&D for FY07

**Dipole, 2T range, single bore (30-50 mm), 0.8 m long, dc,**
**     ****3 microsecond turn-off time, LHe cooled condcutors:   **
**                ****(a) magnetic field shaped by conductor**
**                ****(b) magnetic field shaped by Silicon Steel tape core**
**     ****Goal for FY07: magnetic and mechanical/cryo design**
**2. A 100 kA dc power supply with 3 microsecond turn-off time:**
**                ****(a) switcher cells operating below 100 K, possibly**
**                    ****down to 25 K**
**                ****(b) fast transformer/heater to turn-off the current**
**                ****(c) superconducting dump resistor to expend magnetic**
**                    ****energy**
**     ****Goal for FY07: research and preliminary design**

- A. Zlobin

- 2/24/98

## LER Major Magnet R&D for FY07 

**3. Two-bore (40 mm), high field (7-8 T) vertically bending magnet:**
**    ****set of short (0.8m) 12-15 magnets arranged into a single cryostat**
**    ****Goal for FY07: magnetic and mechanical/cryo design**
**4. VLHC combined function magnet, 1.6 T, 25 and 30 mm gaps:**
**    ****Goal for FY07: magnetic design  **

- A. Zlobin

- 2/24/98