TT2 working group

S Baird, D Berlin, J Buttkus, D Cornuet, G Coudert, G Daems, G Metral

Beams considered 3.5 GeV protons to AD (direct and via TTL2) & D3 -1.2 sec cycles 14 GeV protons to SPS (CT) & D3 - 1.2 sec cycles 20 GeV ions and MD beam to SPS & D3 - 1.2 sec cycles 20 GeV protons to nTOF & D3 in dedicated - 1.2 sec cycles, and parasitic mode - 2.4 sec cycles 26 GeV protons for AD, LHC, SPS & D3 - 2.4 sec cycles

Cycling• Cycling is required if an element has more than two values (incl. zero)• Method is:-

• If new value is below current value - set New directly• If new value above current value then cycle -

Min - Max - New• TT2 pulsed power supplies cannot pulse in less than 900 msecs. • Therefore, for all operational beams, we assume a maximum of 900 msecs to cycle and set the elements of the TT2 line.

PS

AD

SPS

LEP/LHC

TT2(FT16)

TTL2(ATP)

FTA

TT10FTS

TT2AFTN

FT12Dump D3

BTI247

3.5 & 26 GeV Protons direct to AD

nTOF

BHZ247

One exception - BTI247BTI247 has three operational values “zero”, 3.5 GeV direct to AD and 26 GeV direct to AD.

AD can never request 3.5 GeV and 26 GeV protons in the same super-cycle, so BTI247 does not cycle.

BTI247 is equipped with a small auxiliary power supply to compensate the remanent field when setting the power supply to zero. This supply is set to 18.5 amps (re-checked in 2001 start-up)BHZ327 & BHZ377 have similar aux. supplies, which are not used

Initial cycling timesInitially the following power supplies did not meet our 900 msecs criteria:-

Supply Cycle time (msecs) BHZ117 980 BHZ147 1200 BHZ167 960 BHZ377 2000 BVT123 980 BVT173 940 QDE210S 960 QFO205 960 QFO215S 1000 QFO375 960

This cycle time was found to include around 100 msec delay due to the sequential nature of the power supply control.Once CO removed this delay only two elements did not meet our 900 msec. criteria

BHZ147 1200 msecs BHZ377 2000 msecs

PS

AD

SPS

LHC

TT2(FT16)

TTL2(ATP)

FTA

TT10FTS

TT2AFTN

FT12Dump D3

nTOF

BTI147

Dump D2

BHZ147

BHZ147

D2 is never used, therefore the minimum value needed for BHZ147 could be increased, reducing the cycling time

It was possible to reduce the cycle time below 900msec.

BHZ147 is no longer a problem

PS

AD

SPS

LEP/LHC

TT2(FT16)

TTL2(ATP)

FTA

TT10FTS

TT2AFTN

FT12Dump D3

BHZ377

All beams to SPS

nTOF

BHZ377

BHZ377The cycle time cannot be decreased significantly

This restricts the 1.2 second cycles that can be placed before beams for the SPS.

Current solution: Restrict super-cycle composition

Ideal solution: A new, but identical power converter, so that both BHZ 377 and BHZ 378 can be powered separately.Approximate cost estimation 150 kCHf (PO)

PS

AD

SPS

LEP/LHC

TT2(FT16)

TTL2(ATP)

FTA

TT10FTS

TT2AFTN

FT12Dump D3

BTI247

3.5 & 26 GeV Protons direct to AD

nTOF

BHZ247

BHZ247BTI247 does not cycle but it has three operational values “zero”, 3.5 GeV and 26 GeV to AD. The problem is that, when ramping the main supply down to zero, the secondary supply oscillates for 350msec after reaching “zero field”.

Now the only 3.5 GeV beam is for AD but AD can never request 3.5 GeV and 26 GeV protons at the same time. Conclusion BHZ247 is not a problem, but we need remote control & status information for the secondary supply

PS

AD

SPS

LEP/LHC

TT2(FT16)

TTL2(ATP)

FTA

TT10FTS

TT2AFTN

FT12Dump D3

BHZ403

20 GeV Protons to nTOF

nTOF

BHZ403

BHZ403BHZ403 is not cycled. It has only two values.

There were some doubts about the setting time being too long to switch between TOF and D3 for 1.2 second cycles.

After work by PO the power supply for BHZ403 can switch from 20 GeV to “zero” and back as needed. However the remanent field effect in the magnet still has to be checked with beam under all conditions.

ConclusionsBHZ247 needs no further work unless we have another 3.5 Gev user for TT2 (other than AD).We still need remote control and status information etc.

For BHZ377 the solution would be a new power supply for around 150 kCHf

The remanent field at “zero” for BHZ403 needs to be checked with beam.