# Presentation: 097231

## Proposal for a LARP Schottky task

- Andreas Jansson
- Fermilab

- LARP Collaboration Meeting,  April 6-8, 2005

## Why Schottky (Why instrumentation)?	

- The LHC will undoubtedly encounter numerous problems during commissioning and early running. Many are foreseen, some may well be surprises.
- Having proper instrumentation there _from the start_ will certainly help diagnose these issues and reach higher luminosity, faster.

- LARP Collaboration Meeting,  April 6-8, 2005

## Observables

- Average & bunch-by-bunch
- Tunes
- Momentum spread
- Emittance
- Chromaticity

- Useful for
- Beam-bean
- PACMAN
- E-cloud
- ...
- Also useful for
- Cavity phasing
- ...

- LARP Collaboration Meeting,  April 6-8, 2005

## Bunch-by-bunch tune in LHC

- From LHC Project Note 321, W. Herr (2003)

- LARP Collaboration Meeting,  April 6-8, 2005

## CERN tune specs

- Microwave Schottky provides _passive_ _bunch-by-bunch_ tune measurement (and more).
- CERN is specifically requesting this _from the start_!
- Only tune measurement foreseen in store mode!
**No other non-destructive instrument planned with single bunch capability!**

- LARP Collaboration Meeting,  April 6-8, 2005

## Schottky specification

- Schottky is part of the LHC baseline (but not the experience to implement it)!
- Schottky specification now exists!
- We can meet the spec.

- LARP Collaboration Meeting,  April 6-8, 2005

## LARP project criteria

- Luminosity
- Will help understand the machine, and hence increase luminosity.
- Commissioning –
- Requires US-LARP people on location to commission devices.
- R&D
- Some technical challenges in e.g. chromaticity, ramp.
- We are still trying to understand bunched beam Schottky signals in the Tevatron.
- Several beam physics studies requires bunch-by-bunch measurement of e.g. tunes and emittances (beam-beam, pacman, e-cloud).

- LARP Collaboration Meeting,  April 6-8, 2005

## Deliverables/Milestones

- A study of performance limitations in terms of S/N for low intensity bunches using the 1.7 GHz Schottky system installed in the Tevatron.  **(FNAL, FY’06)**
- Design of a traveling wave pick-up structure optimized for the LHC beam and machine parameters. CERN pays for the manufacturing **.(FNAL, FY’06)**
- Design and assembly of four sets of front-end electronics (plus spares) for the pick-ups. This includes all amplifiers, filters, gating and down-mixing circuitry between the pick-ups and the digitizer. CERN provides the gate generator (TTL level), a 40 MHz RF source and the DAQ hardware **(FNAL, FY’06-07)**
- A study of the performance of the DAB board (with 24 bit, 96 kHz ADC mezzanine card) for 1.7 GHz Schottky signals in RHIC and/or Tevatron. **(BNL/FNAL, FY’06)**
- Porting the Fermilab Schottky analysis software to the CERN control system framework. CERN provides the generic controls communications software and the platform for running the code. **(FNAL, FY’06-07)**
- Hardware commissioning with US personnel on location at CERN. This includes transferring expertise to a local CERN designee. **(FNAL, FY’07-08)**
- Beam studies on location at CERN to attempt to e.g. passively measure tunes during ramp and squeeze (this has been difficult in the Tevatron, but may be possible in the LHC due to the much slower ramping). Also attempt emittance and chromaticity measurement**. (FNAL, FY’07-08)**
- Capability to continuously measure the average LHC tune during stores without external excitation. This has shown very useful in the Tevatron, and allows for slow tune feedback during stores, if required. (**FY’07-08)**
- Capability to measure tune of user-selected single bunches in the LHC. Studies of e.g. electron cloud effects and beam-beam detuning of single bunches (PACMAN effect), which are expected to be critical to the LHC performance, will rely on this capability. **(FY’07-08)**

- LARP Collaboration Meeting,  April 6-8, 2005

## Budget estimate

|  | FTE years | M&S |
| --- | --- | --- |
| Design PU structure | 5/12  |  |
| Design & build electronics | 3/12 | $25k |
| DAQ study (BNL+FNAL) | 2/12  |  |
| Port software 
 | 3/12  |  |
| Installation and commissioning | 2/12 | travel* |

- *Two short trips to CERN, plus one longer trip for commissioning
-   for two people each time

- LARP Collaboration Meeting,  April 6-8, 2005

## People

- FNAL
- R.Pasquinelli, P.Lebrun , D.Sun, D.Tinsley, A.Jansson
- BNL
- P.Cameron, P.Oddo
- CERN
- _F.Caspers_, R.Jones

- LARP Collaboration Meeting,  April 6-8, 2005

## Conclusions

- Schottky would be the only tune measurement during store!
- Bunch-by-bunch useful for beam physics (interest from eg T.Sen, JP.Koutchuk, F.Zimmerman)
- It is relatively inexpensive (~1FTE year +$25k+travel)
- Connection to AP task?

- LARP Collaboration Meeting,  April 6-8, 2005