Large spread in measured DT (10 – 40 deg)

0

10

20

30

40

50

60

70

10/0

9/20

11 0

0:00

11/0

9/20

11 0

0:00

12/0

9/20

11 0

0:00

13/0

9/20

11 0

0:00

14/0

9/20

11 0

0:00

15/0

9/20

11 0

0:00

16/0

9/20

11 0

0:00

17/0

9/20

11 0

0:00

18/0

9/20

11 0

0:00

MKI.A5L2.B1:TEMP_MAGNET_DOWN MKI.A5L2.B1:TEMP_MAGNET_UPMKI.A5R8.B2:TEMP_MAGNET_DOWN MKI.A5R8.B2:TEMP_MAGNET_UPMKI.B5L2.B1:TEMP_MAGNET_DOWN MKI.B5L2.B1:TEMP_MAGNET_UPMKI.B5R8.B2:TEMP_MAGNET_DOWN MKI.B5R8.B2:TEMP_MAGNET_UPMKI.C5L2.B1:TEMP_MAGNET_DOWN MKI.C5L2.B1:TEMP_MAGNET_UPMKI.C5R8.B2:TEMP_MAGNET_DOWN MKI.C5R8.B2:TEMP_MAGNET_UPMKI.D5L2.B1:TEMP_MAGNET_DOWN MKI.D5L2.B1:TEMP_MAGNET_UPMKI.D5R8.B2:TEMP_MAGNET_DOWN MKI.D5R8.B2:TEMP_MAGNET_UP

Take worst case

MKI.D5R8.B2:TEMP_MAGNET_DOWN

0

10

20

30

40

50

60

70

08/0

3/20

11 0

0:00

22/0

3/20

11 0

0:00

05/0

4/20

11 0

0:00

19/0

4/20

11 0

0:00

03/0

5/20

11 0

0:00

17/0

5/20

11 0

0:00

31/0

5/20

11 0

0:00

14/0

6/20

11 0

0:00

28/0

6/20

11 0

0:00

12/0

7/20

11 0

0:00

26/0

7/20

11 0

0:00

09/0

8/20

11 0

0:00

23/0

8/20

11 0

0:00

06/0

9/20

11 0

0:00

20/0

9/20

11 0

0:00

04/1

0/20

11 0

0:00

18/1

0/20

11 0

0:00

01/1

1/20

11 0

0:00

T [C

]

Analysis of heating

• Took all fills (to end September) where in stable beams for longer than 10 h

• Considered only time from top of ramp onwards

• Used number of bunches, average bunch current and bunch length as inputs

• Fitted initial heating rate (~linear) over first 2 hours

Analysis (to end September)

0 10 20 30 40 50 60 70 800

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2x 10

14

Fill

p+

Total intensity

0 10 20 30 40 50 60 70 800

0.2

0.4

0.6

0.8

1

1.2

x 10-9

Fill

s

Bunch length

0 10 20 30 40 50 60 70 800

2

4

6

8

10

12

14x 10

10

Fill

Inte

nsity

p+

Bunch intensity

0 10 20 30 40 50 60 70 800

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Fill

Rat

e in

firs

t 2 h

(deg

/h)

Heating rate

Dependencies

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

x 1014

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1x 10

-14

Total intensity p+

Hea

ting

(deg

/h)

Heating * Lb2 * Nb vs total intensityquadratic

Can we model including cooling?• Semi-empirical model makes reasonable predictions

– Replicates cooling after about 12 h– Assuming heating from beam power ( Nb, Ib^2, 1/Lb^2),

cooling from radiation ( DT^4) and from conduction ( DT)

0.00E+00

2.00E+13

4.00E+13

6.00E+13

8.00E+13

1.00E+14

1.20E+14

1.40E+14

1.60E+14

1.80E+14

2.00E+14

324

326

328

330

332

334

336

21:36:00 00:00:00 02:24:00 04:48:00 07:12:00 09:36:00 12:00:00 14:24:00 16:48:00 19:12:00

MKI.D5R8.B2:TEMP_MAGNET_DOWN

fit

LHC.BCTFR.A6R4.B2:BEAM_INTENSITY

Cooling coefficients

• Use cooldowns at technical stops or MDs

295

300

305

310

315

320

325

330

12:00:00 0:00:00 12:00:00 0:00:00 12:00:00 0:00:00 12:00:00

To do...

• Fit all fills with same heating and cooling coefficients– Already started to extract cooling coefficients from

the cooling curve when beam switched off• Update with October data• Extrapolate to 2012 and beyond• Derive some ‘operational’ limitations

Concerns and possible upgrades• Reducing heating of MKIs

– Reduced bunch length/better bunch shaping– New shielding with more stripes

• Question – are temperature rises lower on kickers with more stripes?– Metalised chamber

• Improving vacuum in MKIs– NEG coating of 2nd chamber?– Solenoids around 2nd chamber?– New SIS or SS interlocking/procedures?

• UFOs in ceramic chambers with kicker pulsing– Coating? Cleaning?

• Clearly need to group any upgrades and have common study with all aspects considered