# Overview of Accelerator Physics Integration

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## Talk outline

1.  Beam physics integration: Aims and Objectives

2.  Optics

3.  Beam physics and instrumentation

4.  Basic accelerator physics problems

## 1. Beam physics integration: Aims and Objectives 

-   Three major objectives:

    -   \(1\) Building the model, (2) Machine studies and (3) General
        beam physics coordination

-   Physics model of the entire complex

    -   Optics

        -   Software for optics design, optics meas. and data analysis

        -   Repository of optics files

            -   Set of rules and requirements to the files

    -   Basic accelerator physics problems

        -   The work is mainly performed in system departments

        -   Certain coordination and help are required

        -   Avoiding the duplication of efforts

    -   Instrumentation

        -   Instrumentation problems which require deep insight into
            physics of the device operation

## Aims and Objectives (continue) 

-   Machine Studies

    -   Develop and prioritize study plans

    -   Monitor the study proposals and write-ups of System departments

    -   Enforce an effective use of study time

-   Coordination

    -   Department to department, and Tevatron to CDF and D0

    -   Accelerator physics task forces

    -   Prioritization of the accelerator physics issues for the
        accelerator complex

    -   Weekly meetings (together with Jean Slaughter)

        -   Run II accelerator physics

        -   Beam physics in instrumentation

## 2. Optics

-   **Optics tools and software**

    -   Presently, a number of optics codes are used. Each of them has
        its own drawbacks.

    -   We are building new optics code which should address our present
        and future needs

        -   Main features

            -   Integrated GUI

            -   MAD-8 extension for lattice description

            -   Runable in Linux and Windows

        -   We have all the peaces. Need to glue them together

            -   Schedule

                1.  First public use - this summer.

                    Total duration of active phase - \< 2 years

-   **Optics files repository**

    -   Will address long-standing problem of saving and exchange of
        optics info/files. It is in line with effort to improve magnet
        and survey databases

-   **Optics measurements**

    -   [Differential optics measurements]{.underline}

        -   Present measurements are optimized to minimize study time.
            It fits well for transfer line measurements.

            -   Data taking is fully atomized

            -   Analysis half-manual requires significant time

                1.  \~2 hours for 8 GeV Accumulator-to-MI pbar transport

                    \~2 days for Tevatron but better accuracy is
                    required

        -   Analysis can be improved if data is sufficiently redundant

            -   In collaboration with ANL we build new software

            -   Data acquisition is under testing

            -   Computational engine tests with real machine data are
                expected within month

            -   First, the project is aimed for Tevatron and Debuncher
                where "the optics perfection" is the must. Other
                machines will follow later.

-   **Optics measurements (continue)**

    -   [Turn-by turn]{.underline}

        -   Greatest advantage that it allows one to perform
            measurements much faster

            -   Significant advantage in the case when study time is
                limited

        -   Present

            -   Used at limited number of machines which have reliable
                measurements: MI & Recycler

            -   Coupling and signal decoherence due to chromaticity are
                ignored

        -   Solving Tevatron problems requires expansion of the scope

            -   Coupling

            -   Non-linearities

            -   Effects of signal decoherence due to chromaticity/tune
                spread need to be alleviated

-   **Optics status/priorities**

    -   Tevatron

        -   Low beta optics and helix need to be corrected

        -   Measurements of Tevatron nonlinearities is highly desirable

    -   Electron cooling

        -   The beam is recirculateing but better understanding of
            machine optics is required

        -   Optics redesign for MI-30 is under way

            -   Means of optics correction need to be addressed

    -   Debuncher and AP-2 line

        -   Detailed knowledge of optics and orbits is required to
            maximize the machine admittance

        -   Chromatic correction for AP2 line

    -   Optics correction in the booster and the linac-booster line are
        under study

## 3.Beam physics and instrumentation

-   Many instrumentation problems require deep insight into underlying
    physics

-   We have a weekly meeting to facilitate an interaction of the
    instrumentation department with physicists

    -   Problems to be addressed for the entire accelerator complex

        -   Transverse and longitudinal emittance measurements

        -   Tune measurements

        -   Intensities and efficiencies

## Beam physics and instrumentation (continue)

-   A few problems where the help/coordination has been highly valuable

    -   Tevatron BPM project

        -   Suppression of head-tail motion effects on turn-by-turn
            operation

    -   BLT measurements

        -   Algorithms for signal decomposition and many more

    -   Longitudinal emittance measurements through entire complex

        -   Obtaining quantitative emittance information for the beam in
            strongly non-linear longitudinal potential

    -   Sync-light operation

        -   Radiation from the magnet body

    -   Bunch-by-bunch tune measurements in Tevatron

        -   Significant efforts are required to reach desirable accuracy

## 4. Basic accelerator physics problems

-   **[Recycler]{.underline}**

    -   Analysis of pbar deceleration due to collisions with residual
        gas atoms was helpful in building strategy for vacuum
        improvements

    -   Careful analysis of Recycler operation with stochastic cooling
        was performed

        -   It was found that putting Recycler into operation with
            stochastic cooling only can yield only modest improvements
            for stacking.

            -   Experimental studies carried out now will yield more
                quantitative answer.

            -   Updating the collider scenario with stochastic cooling
                alone will follow

        -   Achieving successful operation of electron cooling has one
            of the highest priorities for the Run II success

    -   Obtaining required small longitudinal emittance with electron
        cooling is based on reduced IBS in the case of equal
        longitudinal and transverse temperatures

        -   Experimental studies of mechanisms responsible for the beam
            heating is under way in Recycler

-   **[Recycler (continue)]{.underline}**

    -   There is considerable progress in measurements of long.
        emittance in barrier buckets

    -   Transverse instabilities

        -   Broad-band transverse damper: setting requirements and
            design

-   **[Electron cooling]{.underline}**

    -   Recently we found out that single IBS (Touschek effect) in the
        electron beam leads to particle loss from recirculation

    -   Optics has been redesigned to alleviate it.

        -   Calculations yield lass reduction by almost factor \~6

        -   Further optics improvements are under way.

    -   Procedures and software for optics correction need to be worked
        out

    -   Absolute energy calibration for Recycler and Electron Cooler
        needs further work

-   **[Antiproton source]{.underline}**

    -   Optics

        -   Optics design

            -   Suppression of chromatic effects in AP2 line

            -   Optics correction for AP2 - P1 8 GeV and 120 GeV to the
                target to accommodate quad tilts in P1 line

        -   Optics measurements and optics matching

            -   Debuncher

            -   D-to-A line

                1.  Has not been measured with present settings. Both
                    empirical tune-up with reverse protons and dif.
                    orbit data needs to be acuired

            -   · Accumulator

                1.  Chromaticity in Accumulator (operationally has not
                    been an issue, but does have the wrong sign at the
                    core for stability in the vertical plane. Is there a
                    fix?)

-   **[Antiproton source (continue)]{.underline}**

    -   Fast pbar transfers

        -   Power supply regulation for AP1 (running AP1 at 8 GeV off of
            120 GeV supplies with ramp cards)

        -   Pbar injection damper in MI: specs on kick and voltage
            required to minimize emittance growth

    -   8 GeV energy definition

        -   Power supply settings for AP2, Debuncher, D-to-A,
            Accumulator, AP3, AP1, P2, P1 with redefined energy (from
            Recycler)

    -   Quad BPM in Accumulator

    -   Stochastic cooling

        -   Understanding of limitations of the stack-tail system and
            recommendation for improvements

-   **[Booster]{.underline}**

    -   Optics

        -   Understand and improve the 400 MeV beam transfer line

        -   Understand and improve booster lattice

    -   Optimize RF capture and early acceleration ramps

    -   Commissioning the collimation system

    -   Orbit control with ramped correctors

    -   Dampers

    -   Transition crossing

-   **[Main injector]{.underline}**

    -   Slip stacking

        -   Beam loading compensation and instabilities

            -   Feedforward

            -   Longitudinal damper

    -   Transition crossing

    -   Single bunch instabilities

    -   Slow extraction optimization

-   **[Tevatron]{.underline}**

    -   Tevatron optics

        -   Linear optics correction

            -   Done at Injection and Flat top

            -   Low Beta optics and helix are in a process of correction

        -   Building non-linear Tevatron model

            -   Presently there is large difference between model
                predictions and observations

        -   Study of sources of orbit drifts

            -   Sources of data: BPMs, water gauges

        -   Feeddown correction of coupling and dif. chromaticities

            -   Additional octupole and sextupole circuits were
                installed at the 2003 shutdown

        -   Further optimization of helices and increase of separation

-   **[Tevatron (continue)]{.underline}**

    -   Model for the luminosity evolution

        -   Measurements of bunch-by-bunch tune shifts and
            chromaticities and comparison with computations

        -   Simulation of beam-beam effects in the presence of diffusion

        -   Experimental study of longitudinal and transverse dynamics
            driven by IBS and beam-beam effects

    -   Instabilities

        -   Transverse instabilities

            -   **⊥** impedance reduced, beam is stable for pos.
                chromaticities

            -   Introducing tune shift by octupoles should improve
                stability

        -   Longitudinal instabilities

            -   Longitudinal impedance measurements

            -   What is the shortest bunch which Tevatron can support

## Conclusions

-   We are making steady progress with luminosity growth and with
    understanding of Tevatron complex operation

-   There is still large potential for further growth of both peak and
    integrated luminosities

-   The progress has been and will be supported by both improvements in
    operations and better understanding of underlying physics

-   Good coordination of beam physics efforts is essential for the Run
    II success