PS/SPS Days

13 Jan 2005, 09:00 → 14 Jan 2005, 13:00 Europe/Zurich

503/1-001 - Council Chamber (CERN)

The Workshop will review the main key issues of the PS&SPS complex and review the work program in 2005-2006 to ensure an efficient start-up in 2006. Chairman Jean-Pierre Delahaye Scientific secretary Roland Garoby Secretariat of the workshop Tjitske Kehrer

Thursday, 13 January

09:00 → 12:30 Session 1 - Committees Review and Recommendations

Conveners: Jean-Pierre (Chairman) Riunaud (AB/ABP), Klaus (Scientific Secretary) Hanke (AB/OP)

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09:00 What is CERN expecting from the AB Department for the coming Years?

Besides its deep involvement in the LHC, the AB department must maintain and upgrade CERN's Accelerators and Beams to fulfill the physics programme as defined in the Medium Term Plan. In particular, recent decisions made by the Research Board after the "Villars meeting" have set the scene of the non-LHC activities for the coming years, with some implications on the AB work plan. The main features of this work plan, with its objectives and milestones, will be presented.

Speaker: Dr Steve Myers (CERN)

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09:20 Can we stop the Degradation of the Operational Performance of our Accelerators?

The overall performance of the accelerators in 2004 will be presented, in terms of beam intensity and availability. This performance will be compared with the original expectations and the performance from previous years. This comparison will reveal a degradation in accelerator performance, possible causes for which will be identified. These will include ageing equipment, reduced maintenance, and a general lack of support for existing accelerators…. Finally, in order to provoke a lively discussion, the possible evolution of the performance, if we cannot reverse this trend, will be shown.

Speaker: Baird Simon (CERN)

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09:50 Will there be enough Protons for Physics in 2006 - 2010?

The capabilities and the performance of the CERN accelerator complex are analyzed, based on the present status of the accelerators. This is done by estimating the availability of proton beams for the period 2006 to 2010 and comparing it to the anticipated physics programme, to highlight any possible shortfall, especially for SPS physics. Typical operation scenarios with yearly running periods and machine availabilities are defined, including specific assumption for LHC beam requests during the first years of operation, based on LEP experience. The present performances of the accelerators in terms of available beam brightness, maximum intensity per cycle and repetition rate are used for the analysis. Functional relationships between the beam availabilities for the various users are discussed. Special emphasis is given to operations that imply important beam losses along the accelerator chain and the most relevant consequences are outlined.

Speaker: Dr Michael Benedikt (CERN)

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10:20 Machine Studies: What did we achieve, what remains to be done and what could be improved?

In 2004 an ambitious programme of machine studies has been conducted in the PS and SPS complex. Beams for LHC commissioning and physics have been prepared in the injector chain and progress has been made in the understanding and in the solution of the present performance limitations. The SPS has been heavily used as a test-bed for LHC hardware prototypes and to study the electron cloud build-up and scrubbing in cryogenic surfaces. Excellent results have been obtained also in the preparation of the PS and SPS complex for the CNGS challenge both in the new multi-turn extraction scheme in the PS and in the revival of the high intensity beams. After an overview of the status of the LHC and high intensity beams and of the main (preliminary) results of the machine studies, the main performance limitations of the PS-SPS accelerator chain and the outstanding issues for future studies will be outlined. Finally a summary will be given of the recommendations issued by the APC to improve machine performance, to increase the efficiency of the use of Machine Development time and to make new beams operational.

Speaker: Gianluigi Arduini (AB-ABP)

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10:50 coffee break

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11:10 Installations, Modifications, Consolidation in 2005: What is planned, and can we do it?

After one year of shut-down, at the restart of the PS&SPS complex in 2006, all the injector chain for the LHC and all accelerators for the Physics should work as reliable machines. The major installations, modifications and consolidation work will be reviewed for Linac2, PSB, PS, SPS, AD and transfer lines. The following questions “what is planned in 2005?” and “what could delay the start- up?” will be addressed. In addition, the interferences with projects (I-LHC, SLI, LTI, CNGS, CTF3, and Linac4) will be mentioned.

Speaker: Louis RINOLFI (CERN)

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11:40 What is the Future of the Experimental Areas?

The present layout, capabilities and performance of the CERN fixed target experimental areas are described, in particular the North and East areas, nTOF, Isolde and the AD. The future possibilities and known modifications will be outlined, taking into account the expected evolution of the accelerator performance and the recommendations from the Villars meeting of the SPSC. Consolidation requests as well as possible adaptations to new suggested experiments or requirements will be presented.

Speaker: Lau Gatignon (CERN)

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12:10 How will we cope with Safety in the long Shutdown?

The international Safety Rules concerning the Access to radioactive areas are requiring the closure of the PS Complex during the shutdown. In order to comply with this rules, a new access procedure based on the existing system, will be implemented in the period December 2004 - Easter 2006. The modifications introduced in the Inflector area and the possible scenario(s) concerning the Operation from the new CCC in 2006, will be presented.

Speaker: Paolo Cennini (CERN)

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14:00 → 17:30 Session 2 - Shutdown Activities in 2005

Conveners: Elias (Scientific Secretary) Metral (AB/ABP), Gianluigi (Chairman) Arduini (AB/ABP)

14:00 What is falling apart in the injector chain

Equipment groups have been asked to propose activities to consolidate their hardware and for each system concerned, a risk analysis has been made and the impact of failures has been evaluated. The method used for the analysis will be explained, a prioritised list of activities will be presented and those which are planned to be carried out will be indicated.

Speaker: POOLE John (CERN)

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14:20 What is falling apart in the technical services for the PS&SPS complex

Following a request by the DG, early last year, the TS Department made an analysis of the risks associated to the construction and operation of the LHC. It focused on the infrastructures under the responsibility of the Department and singled out a number of items which, if not consolidated, would seriously jeopardize CERN’s ability to complete the LHC project in time. This exercise led to the establishment of priorities which were found in agreement with those set by a similar analysis carried-out in the AB Department. The talk will present the consolidation projects which impact on the operation of the PS and SPS together with their implementation schedule.

Speaker: Roberto Saban (CERN)

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14:40 Renovation of the 45-year old PS magnets

The PS main magnet renovation program comprises two phases in which all PS main magnet units will be refurbished. Phase 1 will take place during the long PS shut down in 2005 and foresees the renovation of 40 magnets. The actual state of all magnets has been evaluated and analyzed in order to identify the weakest magnets. These magnets will be removed from the PS tunnel, completely dismantled and equipped with new main coils and new pole-face-windings. This presentation gives an overview about the magnet evaluation method and the manufacturing status of the new components. Aspects related to refurbishment, test and re-installation procedures will be discussed.

Speaker: Mr Thomas Zickler (CERN)

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15:00 Reliable and easy-to-use instrumentation for a difficult start-up

It is during startup and commissioning of new features in the accelerator that beam instrumentation is mostly needed and it is also during these periods that most of the instrumentation problems crop up. In this talk we will analyze problems that have occurred during the 2004 startup, and try to find reasons for failures and ways to improve in the future. The situation of the PS and PS-Booster wire scanners and actions taken during the year as well as during the 2005 shutdown will be presented. Several sensors destined for the LHC have been tested in the PS complex and in the SPS. Preliminary results of these tests will be reviewed.

Speaker: Dr Uli RAICH (CERN)

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15:20 coffee break

Coffee break

15:40 How to get reliable PSB sieve and PS&SPS dumps for 2006?

During the last two years of operation the PS internal dumps and the PSB sieve showed a significant diminution in reliability. The availability of one PS dump and of an operational spare is the prerequisite for some modes of operation (e.g. nTOF in parasitic mode of East hall). The PSB sieve is absolutely required for the production of the pilot LHC beam. In the SPS the high energy beam dump absorber (TIDVG) presents signs of beam damage which reduce the mechanical aperture available for the beam (in particular the high intensity ones). The current status of this beam intercepting devices, operational issues and the planned renovations in 2005 will be discussed. A schedule about the future transfer of responsibility for the stepping motors for all the collimators of the PS&SPS complex to the ATB group will be given.

Speaker: Roberto Losito (AB-ATB)

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16:00 Operating the septa beyond their design specs

Recent septa failures will be briefly reviewed, along with a discussion of the spares policy, the role of preventative maintenance and the reformulated consolidation proposal. The importance of passive septa protection devices and well- thought interlocks will be highlighted. The impact from planned or possible future modes of operation will be discussed.

Speaker: Mr Jan Borburgh (CERN)

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16:20 The way to fast and "loss-free" SPS kickers

After modification in the 2003/2004 shutdown the overall injection kicker rise time was quantified more precisely. The improvements for four-batch LHC type beam injection have not yet been fully reproducible. The present status will be presented and possible further improvements be discussed. An overview of the extraction kicker modifications made to meet the LHC and CNGS requirements will be given. The 2004 operational experience with the horizontal tune kicker, equipped with metallised ceramic inserts in the previous shutdown, will be reported. Further developments to reduce the SPS kicker beam impedance and heating will be discussed, along with first results from laboratory tests and possible implementation schedules. Prospects for further improvements beyond 2006 will be briefly outlined.

Speaker: Dr Enrique Gaxiola (CERN)

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16:40 What remains to be done to have ISOLDE fully integrated and REX fully operational?

The ISOLDE REX post accelerator is now fully operational. The top energy of the linac is 3 MeV/U and so far more than 25 isotopes of 12 elements have been cooled, bunched, charge bred and accelerated with the system. The REX system is since 1 January 2004 under the responsibility of the AB department. For an interim period of 3 years the associated cost, both manpower and material, is covered by the ISOLDE collaboration. The aim is to integrate REX fully as an AB machine during this interim period. The REX team has very successfully maintained and operated the facility with 90 eight hour shifts of radioactive beam delivered for physics in 2004. The main problems experienced in 2004 have been a lack of manpower during peek periods such as setting-up of REX (isotopes are changed frequently), a shortage of technician support for the REX low energy stage (trap and EBIS) and the support for the non AB standard control system. The integration work in 2005 will focus on a new organization for the work at the low-energy stage, a proposal for a new control system (both low and high level) and the formation of a supervisor team for a more efficient and human (legal hours) operation of REX.

Speaker: Dr Mats Lindroos (CERN)

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17:00 How can we restart the AD in 2006?

From 2006, the AD will enter a second period of running with improved apparatus and new physics programs at the ATRAP, ATHENA, ASACUSA and ACE collaborations. The required consolidation for a successful restart of the AD in 2006 will be reviewed. Improvements in beam characteristics stability and experiment switching delays will also be discussed.

Speaker: Mr Tommy Eriksson (CERN AB/OP/AD)

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Friday, 14 January

09:00 → 13:00 Session 3 - Preparation of Restart in 2005-2006

Conveners: Rende (Scientific Secretary) Steerenberg (AB/OP), Roland (Chairman) Garoby (AB/RF)

09:00 Will PS&SPS be ready for CNGS start-up in 2006?

The PS&SPS complex has to provide 4.5 10^19 protons on CNGS target per year. This number was initially based on the SPS intensity record obtained in 1997 (4.8 10^13 p/p at 400 GeV/c). During high-intensity tests in September 2004, a new intensity record has been established, exceeding by more than 10% the previous one, with reasonable losses. This talk reviews what was expected before the tests, what was obtained and what was learned for the future high-intensity operation. Both beam and equipments will be discussed, and the issues for the high-intensity start-up in 2006 will be presented, assuming the nominal 1.2 s basic period in the PS complex.

Speaker: Dr Elias METRAL (CERN)

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09:20 How far can we increase the Intensity per Pulse for CNGS?

The nominal proton intensity per CNGS pulse is 4.4x10^{13}. This number is only slightly below the intensity record achieved in the SPS in 1997 after careful tuning of all the accelerator complex. Since this time the PS and SPS machines have had major upgrades in preparation for the LHC beam. In September 2004 a total intensity of 5.3x10^{13} was accelerated to top energy in the SPS after a 3 week dedicated run with the CNGS beam. The limitations found in all rings are presented together with the steps that will be necessary to make this intensity operational. Possibilities for further intensity increase are also discussed.

Speaker: Elena Shaposhnikova (AB/RF CERN)

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09:40 When can we have a clean Multiturn Extraction from the PS?

Since the year 2002 intense efforts were devoted to the experimental verification of the proposed multiturn extraction based on beam capture inside stable islands of transverse phase space. Such an extraction is aimed at reducing the losses of the present Continuous Transfer used for the fixed target physics programme at the SPS and in particular for the high-intensity beam for the CNGS project. Splitting of a high-intensity, single-bunch proton beam was achieved without detectable losses. Furthermore, detailed measurements were performed to understand better how to change the beam parameters at the end of the capture process. In this presentation the main experimental results achieved in the year 2004 will be summarised. The focus will be on the outcome of the study for the implementation of the proposed extraction technique as a replacement of the present Continuous Transfer. The new extraction layout will be presented as well as cost estimate, schedule, and possible scenarios for the construction and commissioning.

Speaker: Dr Massimo Giovannozzi (CERN)

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10:10 Should we prepare for using a 900 ms basic period in the near future?

The “basic-period” is the underlying time unit for the operation of the accelerators in the sense that all machine cycles are integer multiples of that unit. The motivation for reducing the basic period from the present 1200 ms to 900 ms and the choice of this “optimum” length are explained. The impact on the operation of the accelerator complex is discussed and an overview of the expected beam performance for the various physics users is given. The requirements for the main technical systems of the different machines and transfer lines are summarized. The schedule for implementation over the period 2005-2007 is presented, as well as the status of approval of the project.

Speaker: Dr Michael Benedikt (CERN)

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10:30 Coffee break

Coffee break

10:50 Can we afford to re-start the SPS in 2006 without multicycling?

From 2006 onwards, LHC studies, CNGS and other fixed target physics programs will compete for beam. Besides, the timing equipment currently driving the SPS cycling is not compatible with PS Complex and with the future LHC cycling flexibility. Multicycling the SPS is a solution for both problems (together with speeding up the basic cycling period to 0.9s) and a firm decision must taken on this possibility. The talk will present the motivations for multicycling the SPS from 2006, then it will give details on the changes to be made in the equipment together with their cost in money and manpower. As a conclusion, the expected benefits for both physicists and operation will be presented.

Speaker: Bertrand Frammery (CERN)

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11:20 Can we sufficiently protect the SPS and its extraction lines against damages in multi-cycling and high intensity beam context?

In the LHC and CNGS era, the beam energy of the SPS will be largely above damage limit. Comparing to the current SPS exploitation, fast extractions into several channels of higher intensity and brighter beams are very challenging. In order to optimize the operation efficiency, a “flexible” but reliable Interlock system operating in multi-cycling mode is required. Ideas for such system, the role of the Timing system and the software interlock are discussed. The different inputs of the Interlock system are reviewed, and interlocks for safe beam extraction are proposed. First experiences with the new SPS Extraction Interlock system used this year for Ti8 extraction are reported.

Speaker: Mr Bruno Puccio (CERN)

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11:40 How many protons can we afford to loose anually in the PS Complex?

The CNGS target will receive up to 4.5E19 protons in one year. To achieve this goal,approximately 1.3E19 protons will be lost in the PS, 50 % during acceleration and 50% during multiturn extraction. This contribution analyses the radiological consequences of the increased beam losses. It is focussed on two main issues: 1.) Radiation leaking through the weak points of the PS shielding (skyshine effect),exposing personnel working on the CERN site and members of the public outside of CERN. 2.) Activation of material in the PS and consequently, personal doses during maintenance. The estimates are confronted with measurements made during the test phase in October 2004. The consequences of the increased beam intensity include the risk of exceeding dose limits at the CERN fence, the unjustified exposure of personnel on the CERN site and an increase of personal doses during maintenance. These effects can be mitigated by a systematic reduction of losses in the PS. Until then, intensity limitations and longer waiting times before performing maintenance may be required.

Speaker: Dr Thomas Otto (CERN SC-RP)

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11:55 How many protons can we afford to loose annually in the SPS and its beam lines?

From 2006 onwards the total number of protons per year accelerated by the SPS machine and provided to its fixed target program, CNGS and LHC will exceed by far all what has been achieved in the past. The consequences with respect to radiation protection issues will become serious. Additional thick shielding will be required in the caverns of SPS Point 4 and Point 5 if ECA4 and ECA5 shall remain accessible during beam operation. The total number of protons on the beam dumps in BA1 will be limited by the effective dose received by members of the public via the emission of gaseous radioactivity from TT10. Either AB’s operation group will strictly respect a pre-defined quota of protons on the SPS beam dumps or the displacement of the dumps to a more favourable location will be required. The radiation dose rates during shut-downs will be strongly increased when compared to previous years. The dose to the maintenance personnel will be high if no corrective measures will be applied like the use of remote handling devices or of radiation hard material. Job and dose planning will become anyhow obligatory. Last but not least, the number of protons accelerated by the SPS shall be justified.

Speaker: Doris Forkel-Wirth (CERN-SC)

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12:20 Can we operate CERN's Technical Infrastructure from the MCR efficiently?

The operation of CERN's Technical Infrastructure will move from the TCR to the MCR on February 1st 2005. AB will take the responsibility for monitoring all technical services including electricity supply, cooling&ventilation, computers&networks and various access and safety systems, co-ordinating minor and major interventions of all equipment specialists and provide this service 365 days per year and 24 hours per day. The layout of the MCR will change as one of the current MCR consoles will be replaced by furniture from the TCR and, during a two-year period, the technical services will be operated by a single operator on shift instead of two to allow re- allocation of the second operator to other tasks. The immediate impact on the technical infrastructure operation is that on-site interventions can only be done by equipment on-call services and no longer by the operators, hence causing delays.

Speaker: Mr Peter Sollander (CERN AB/OP)

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12:40 Towards the CCC

The restart of all accelerator operation in 2006 is foreseen to take place from the CERN Control Centre (CCC), currently being built adjacent to what used to be the PCR. The status of this project will be summarized, covering the building, the control room layout and the staff who will work there. The overall schedule will be presented, and some particular issues for the 2006 startup will be highlighted.

Speaker: Dr Simon Baird (AB/OP)

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