Minutes of the Linac4 Technical Design Committee

meeting no. 3

date: 13 June 2006

present:

AB/RF	M. Pasini, J. Broere, R. Wegner, C. Rossi, M. Paoluzzi, M. Vretenar
AB/ABP	G. Bellodi, A. Lombardi, E. Sargsyan, Th. Meinschad
AB/BI	U. Raich
AT/CO	J. Serrano
AB/BT	W. Weterings
AB/OP	K. Hanke
TS/CV	Y. Body
TS/CE	A. Lopez
TS/SU	M. Jones
AT/VAC	E. Page
AT/MME	Y. Cuvet
AT/MEL	T. Zickler

excused: E. Mahner, O. Brunner, W. Venturini

agenda

1. Status of PSB Injection Design (W. Weterings)
2. Beam Diagnostics Specifications for Linac4 (K. Hanke)
3. First estimate of electrical power requirements for Linac4 (F. Gerigk)
4. Status of Technical Design Report preparation (M. Vretenar)
6. next meeting

1. Status of PSB Injection Design (W. Weterings)

After recalling the present layout of the PSB Injection line and the way beam separation presently works, were introduced the main guidelines for the new separation system at 160 MeV. The basic idea is to maintain as much as possible the current layout and adapt the distributor and the vertical septum to give identical deflection angles at 160 MeV as now at 50 MeV (factor 1.9 in integrated field). Moreover, septum aperture has to be reduced and few dipoles and quadrupoles have to be modified or replaced. The conclusion is that the distributor can be modified, while a new septum has to be built. Rise time of the distributor will be less than 1 μs, and it is requested to the linac to provide 1 μs gaps in the beam pulse for distributor rise time. In order to simplify operation, distributor pulse lengths will be fixed, and the required flexibility in operating rings and number of injection turns will be provided by adjusting the distributor timings. H^- and painting schemes are still under study.

Discussion:

• it was stressed that renovation of the distributor was already included in the PS consolidation budget.
• The linac could have some problems in providing the 1 μs gap in the beam pulse, because of excessive voltage ripple in the linac cavities. It is asked to study the implications of a reduction of the distributor rise time to 500 ns.
• For the TDR, it will be important to estimate the increase in electrical power consumption and in cooling with respect to the present scheme.

2. Beam Diagnostics Specifications for Linac4 (K. Hanke)

The diagnostics is divided in 2 groups: diagnostics for commissioning and for day-to-day operation. For commissioning of RFQ and chopper line will be used the IPHI diagnostics line, whereas for commissioning of DTL will be assembled a movable diagnostics bench. CCDTL and SCL will be commissioned using the measurement lines at linac end. During operation, information will come from beam transformers and from special pick-ups providing position phase and intensity. A preliminary list of diagnostics has been prepared. Input is needed from BI on the particular diagnostics equipment to be used.

Discussion:

• a Time Of Flight energy measurement could be used during commissioning, however it would be advisable to have a spectrometer at least for DTL measurements (one of the LBS magnets?).
• space for steerers and vacuum valves is not included in the layout prepared by the diagnostics team. Whereas valves are clearly out of its tasks, steerers should be specified by the beam dynamics and then integrated in the same layout of BPM and other diagnostics (Action: A. Lombardi and M. Pasini).

3. First estimate of electrical power requirements for Linac4 (F. Gerigk)

The design team has to provide an estimate of the electrical power consumption for Linac4. A calculation of the amount of power required by the RF for pulsed operation comes to only 60 kW. However, the actual klystron efficiency is difficult to estimate, as well as the off-pulse klystron current. For power supplies, the PO group should give an estimation, while we should calculate the requirements for air conditioning and for cooling pumps. The groups involved are asked to provide information before mid July.

Discussion:

• it was observed that in the case of low duty RF operation, the power needed by the klystron and tube filaments is probably higher than the power needed to produce the RF pulse.

4. Status of Technical Design Report preparation (M. Vretenar)

The structure of the Technical Design Report (TDR) has been updated, with some additions in the list of contributors. The latest version is available on the web site. Deadline for contributions was end of May, and only 4 contributions out of 32 were received (12%)! It is important to send the missing contributions before the end of June, because they are needed to provide input to the technical design that has an extended deadline (end of July), and because the editing of a more or less complete version has to start as soon as possible in order to meet the deadline.

next meeting:

Tuesday July 25th, 14:00, room 354 1-001

-- MaurizioVretenar -