# Presentation: 183796

## LHC Injector Upgrade Plans(and how we might get involved)  

- Jean-Francois Ostiguy
- APC/AP

## BEAM07 CARE-HHH/  Workshop

- Good representation from FNAL and US (through LARP) at this 1-week  workshop.
- Focused on LHC: beam-beam mitigation, noise and vibrations, luminosity leveling, collimation strategies, etc were covered. A block of talks dedicated to FAIR (GSI).
- One distinct sub-theme ( one day of focused presentations) was an elaboration on plans for  staged upgrades of the LHC injector chain.
- My main objective: get acquainted with people involved in simulation and studies connected with the LINAC3 and Booster upgrades and possibly the SPL ( details follow).

## Credits – More Information

-    This talks contains, information and figures selectively lifted from the contributed presentations.
-    The original talks + a lot more information can be found at the Indico site accessible from the main workshop url:
** ****http://care-hhh.web.cern.ch/CAREHHH/BEAM07/default.html**

## Injector Chain – Simplified View

## LHC Emittance Budget 

| Machine | Energy | Intensities
(nominal) | Emittance
(rms, mm-mrad) | Intensities
(Ultimate) | Issues |
| --- | --- | --- | --- | --- | --- |
| RFQ | 750 KeV | 200 mA | 0.5-1.0 | 200 mA |  |
| Linac2 | 50 MeV | 180 mA | 1.2 | 180 mA | reliability |
| PSB | 1.4 GeV | 1.0E12
 (ring) | 2.5 | 1.8E12 | Space charge |
| PS | 25 GeV | 0.84E13 
(Pulse) | 3.0 | 1.4E13 | Transition, impedance
> 10% losses  |
| SPS | 450 GeV | 1.5E11(bunch) | 3.5 | 1.7E11 | Low injection E,  reliability, e-cloud, impedance
> 10% losses |
| LHC | 7 TeV | 1.15E11
(Bunch) | 3.75 | 1.7E11 |  |
|  |  | 1 x 1034 |  | 2.5x1034 |  |

## Injection Scheme Cartoon (Obsolete,but useful)

## Linac4 /SPL/PS2 on the CERN Site

- PS2 (2016 ?)

- Low-duty SPL (2015 ?)

**Linac4**
**(2012)**

- 1st stage: Linac4 injects into the old PSB  increased brightness for LHC, more 	 beam to ISOLDE, increased reliability.
- 2nd stage: Linac4 into SPL (and PS2)  renewed and improved LHC injection chain.

## Linac4 Layout

**CCDTL**

**PIMS**

**3MeV**

**50MeV**

**94MeV**

**160MeV**

**Drift Tube**
**Linac**
- 352 MHz
- 18.7 m
- 3 tanks
- 3 klystrons
- 4 MW
- 111 PMQs

**Pi-Mode Structure**
- 352 MHz
- 22 m
- 12 tanks
- 8 klystrons
- ~12 MW
- 12 EMQuads

**Cell-Coupled Drift Tube**
**Linac**
- 352 MHz
- 25 m
- 21 tanks
- 7 klystrons
- 6.5 MW
- 21 EMQuads

- RF Duty cycle:
- 0.1% phase 1 (Linac4)
- 3-4% phase 2 (SPL)
- (design: 10%)

- 4 different structures, (RFQ, DTL, CCDTL, PIMS)

- Total Linac4:
- 80 m, 18 klystrons

- Ion current: 40 mA (avg. in pulse), 65 mA (bunch)

**CHOPPER**

**RFQ**

- Chopper
- 352 MHz
- 3.6 m
- 11 EMquad
- 3 cavities

- Radio
- Frequency
- Quadrupole
- (IPHI)
- 352 MHz
- 6 m
- 1 Klystron
- 1 MW

**H-**

**3MeV**

**95keV**

- RF volume
- source
- (DESY)
- 35 kV
- Extrac.
- +60kV
- Postacc.

**DTL**

## Contacts

-    I had discussions regarding possible collaboration with the following individuals:
- Gianluigi Arduini (Initial contact, management)
- Christian Carli (Injector Operations, oversees the simulation work)
- Frank Gerigk ( involved in Linac4 conceptual design, and injector simulations, now working on SPL)
- Matsumitsi Aiba ( CERN “fellow”: the guy who is currently doing the  simulation work)

## Some areas where we can contribute

- The current injection scheme does not rely on charge exchange – the new one does. We do have a long operational experience with this.
**Simulations **
**space charge mitigation strategies: e.g.phase space painting, “neutralization regions”, etc  **
-  linac microstructure – (long space-charge)
- decoherence

- We have some experience with ORBIT
- (used in Booster simulations and now in
- MI simulations). There is also interest in
- ESME studies.

## Emittance Evolution (M. Aiba)

- Simulation in PSB
- Proton beam
- _Bunched beam_
- 3.25E12 protons / ring
- Gaussian dist., 2.5 m
- Electron lens
- _DC_ localized, ~2 m * 4 lenses
- Various currents, 10 keV
- Gaussian dist., 2.5 m

## Emittance Evolution Studies in PS Booster ( M. Aiba)

- Elliptic distribution
- 2.5 m normalized r.m.s. emittance
- Macro particles =100,000 (limit in ACCSIM)
- Flat bottom

- - Sensitive to number of grids
-  Sudden blow-up in vertical
-   (ORBIT)

- - Rather good agreement
-    in horizontal

- (ACCSIM simulation by M. Martini)

- Comment: predicted emittance blowup is likely to be a numerical artifact.

## SPL

- SPL = Super Conducting Proton Linac
- Some form of  an SC linac has been under consideration at CERN for many years.
- The SPL refers to a 5 GeV SC linac based on Tesla (xfel) technology, with rf distribution based on klystrons feeding multiple cavities with fast ferrite phase shifters to provide individual amplitude and phase control.
-  The PS would ultimately be eliminated
-  Potentially lots of commonality with Project-X

## SPL – 2 phases

**low-power **operation (LPSPL): injection into PS2
- 1.5 x 1014 particles per pulse (H-), 1 Hz (design for 2 Hz),
- 4 GeV, 0.2 MW
- 1.2 ms pulse length for 20 mA average pulse current.
**high-power **operation (SPL): PS2 plus high-power
- > 1.0 x 1014 particles per pulse (H-), 50 Hz,
- 5 GeV, 4 MW,
- 0.4 ms pulse length for 40 mA average current.

## PS2 - > injection from SPL

**SPS**

**SPS+**

**Linac4**

**(LP)SPL**

**PS**

**LHC / **
**SLHC**

**DLHC**

- Output energy

**160 MeV**

**1.4 GeV**

**4 GeV**

**26 GeV**

**50 GeV**

**450 GeV**

**1 TeV**

**7 TeV**

**~ 14 TeV**

**Linac2**

**50 MeV**

**(LP)SPL: (**Low Power)** **Superconducting Proton Linac (4-5 GeV)
**PS2:** High Energy PS
- 	(~ 5 to 50 GeV – 0.3 Hz)
**SPS+: **Superconducting SPS
- 	(50 to1000 GeV)
**SLHC**: “Superluminosity” LHC
- 	(up to 1035 cm-2s-1)
**DLHC**: “Double energy” LHC
- 	(1 to ~14 TeV)

**PS2 - > injection from SPL**

**PS2**

**Present accelerators**

**Future accelerators**

** ****(LP)SPL is the baseline ****	****injector for PS2**
** ****PS2 will use nc magnets**
** ****PS2 size is 15/77 of ****	****SPS**

## PS upgrade – “PS2” Issues

-  magnet technology
- instabilities + impedance : seems to be manageable at proposed intensities.  Comparable to MI (project-X version) : intensity, ring dimension, cycle time (V. Lebedev)
- e-cloud and vacuum chamber design
- Optics: real or imaginary gamma-t ?
- CERN studies - I. Papaphilippou
- Imaginary gamma-t lattice design and optimization_**Extremely good**_ talk by Y. Senichev (F. Juelich)
- Steve Peggs: experience at BNL with “localized”jump. Stick to conventional FODO lattice ?

## Localized gamma-t (S.Peggs + M. Bai)

- Beta waves advance twice as fast as dispersion waves
- Pairs of jump quad doublets confine dispersion
- _Real phase advances are never exactly 90 degrees_

## Localize gamma-t (S. Peggs + M. Bei)

- G families change g T, Q families compensate tunes
- _Imperfect optics:_
- 1) some dispersion leaks into the Q family
- 2) phase advances are not constant, or near 90 degrees

## Gamma-t Jump or no Jump ?  This Should Not Be a Religion (Peggs)

- AGS has 2nd order jump
- RHIC has 1st order jump
- J-PARC will provide operational experience with imaginary gamma-t
- _MAIN Injector will demonstrate an “optimized” gamma-t jump (needed for project-X) _
-      Could implementation of gamma-t jump in MI be “fast-tracked” ?_ _

## There is some interest ...  ( R. Garoby)

- The pace of work is good and will accelerate in the near future.
- We have to strengthen our links with the community and establish new collaborations.

- We need You !

## Conclusion

- There is some potential for involvement on the part of FNAL in the injector upgrade projects.
- These projects are of direct relevance to our own future high intensity upgrades
-  As a very modest “entry point”, I have agreed to perform some ORBIT simulations to resolve numerical noise issues and help with modest modifications. I may also provide some support for ESME simulations.