2010 MQW measurement campaign and updated

FIDEL LHC models

P. Hagen and E. Todescomeasurements by M. Buzio, R. Chritin, J. G. Perez

beta-beating analysis by R. Tomas Garcia (BE/ABP)

May 2010

2

Lessons learnt from LHC beam commissioning

o The measured β-beating after the FIDEL update of the MQW models in January 2010 demonstrated that there are STILL errors in the transfer function in the order of 1 or 2% in MQWA, much more in MQWB

o We decided to initiate a new measurement campaign measuring 2 of the 4 spare magnets in MQWA and MQWB mode

o The working assumption being that the difference in pre-cycle of series measurements vs. “as used” in LHC would be the main source of error

o The I_MIN of the MQWA power supply could change in the future due to stability issues, so we added a few extra pre-cycles in the measurements, in case we would need them

o The new measurements will be used to re-adjust, recalibrate the transfer of all 48 MQW A+B magnets in LHC|

o Use SSW measurements for fast and precise Bdl integrals

3

MQWB pre-cycle

-600

-400

-200

0

200

400

600

0 500 1000 1500 2000

I (A)

t (s)

Pre-cycleNo of periods 4ramp rate (A/s) 5I_MIN (A) -600t_MIN (s) 10I_MAX (A) 600t_MAX (s) 10

MQWA pre-cycles

0

100

200

300

400

500

600

700

800

0 500 1000 1500 2000 2500 3000

I (A)

t (s)

I_min

I_flat_topPre-cycle type a b c dNo of periods 4 4 4 4ramp rate (A/s) 2 2 2 2I_MIN (A) 0 20 30 35t_MIN (s) 10 10 10 10I_FLAT_TOP (A) 710 710 710 710t_FLAT_TOP (s) 10 10 10 10

4

MQWA results…

SSW comparison with old series meas

-800

-600

-400

-200

0

200

400

600

800

0 200 400 600 800

TF

(uni

ts)

Current (A)

MQW 10 ap 1a

b

c

d

Shape of TF wrt pre-cycle

I a b c d a b c d

200 0 0 0 0 -21 -21 -15 -18710 -6 -6 -6 -6 -15 -14 -14 -15

ap1 ap2

MQW 51 comparison ( new SSW minus old RC in units)

5

Zoom on hysteresis

Shape in table format

I a b c d series

30 133 358 57435 111 258 369 50338 92 212 304 39440 70 187 276 34070 2 38 59 73

100 -6 6 18 12200 0 0 0 0400 -6 -11 -13 -13500 -32 -38 -38 -37561 -74 -78 -79 -80610 -164 -170 -172 -173

710 -599 -604 -606 -606

MQW 10 ap1

TF (units)I a b c d series

30 113 325 53935 92 241 348 46738 68 191 289 36940 50 152 258 32170 -2 27 47 62

100 -18 -2 4 11200 0 0 0 0400 -8 -9 -12 -10500 -35 -36 -40 -36561 -79 -80 -84 -79610 -168 -173 -176 -172710 -606 -610 -613 -609

MQW 10 ap2

TF (units)

Pre-cycle type a b c dNo of periods 4 4 4 4ramp rate (A/s) 2 2 2 2I_MIN (A) 0 20 30 35t_MIN (s) 10 10 10 10I_FLAT_TOP (A) 710 710 710 710t_FLAT_TOP (s) 10 10 10 10

6

MQWA 51 shape

-100

0

100

200

300

400

500

600

700

0 50 100 150 200

TF

(uni

ts)

Current (A)

MQW 51 ap 1a

b

c

d

I a b c d 51 series

30 175 417 62135 147 302 433 55338 115 257 357 44140 95 220 314 399 12970 1 45 74 90

100 -14 6 21 24200 0 0 0 0 0400 -29 -27 -23 -23500 -69 -61 -60 -58561 -115 -111 -112 -109610 -213 -208 -205 -207

710 -655 -651 -649 -648 -649

TF (units)

MQW 51 ap1

I a b c d 51 series

30 136 364 55835 110 267 380 50538 75 219 323 40340 60 183 274 355 12070 -4 35 45 71

100 -13 8 8 15200 0 0 0 0 0400 -21 -20 -25 -23500 -57 -58 -64 -59561 -108 -107 -115 -110610 -203 -205 -209 -220710 -644 -643 -649 -647 -650

MQW 51 ap2

TF (units)

7

MQWA measurement conclusions

o Combine series measurements with new measurements of 4 apertures with pre-cycle “B” (I_MIN=20 A)

o MQWA 51 has good match between old and new measurements for I >= 100 A

o MQWA 10 was not measured during series measurements!

o Assume MQWA 10 + MQWA 51 represent the population

o Replace hysteresis part of old transfer function with new shape (points where I < 200 A)

o No strong justification for doubting the absolute calibration of series measurements so keep the old TF geometric @ 200 A “as is” ! ?

8

MQWA FiDeL 2010

fit of 2 magnets

fit of 2 magnets

fit of 2 magnets

sigma(1) 0.00053814I0(1) 766.25s(1) 4.08820840Inomref(1) 710

rho 0.00004855r 2.71513904Iinjref 40

I TF ave (u) TF sigma (u) source why

30 366 38 SSW 2010 pre-cycle35 267 26 SSW 2010 pre-cycle38 220 28 SSW 2010 pre-cycle40 186 28 SSW 2010 pre-cycle70 36 7 SSW 2010 pre-cycle

200 0 0 all by def normalisation300 0 14 RC ORIG all magnets400 -17 8 SSW 2010 extra point500 -48 13 SSW 2010 extra point561 -94 18 SSW 2010 extra point710 -631 18 RC ORIG all magnets810 -1249 17 RC ORIG all magnets

MQWA TF synthesis

9

MQWA current predictions @ 450 GeV

CIRCUIT G (T/m)I (A) I (units) I (A) I (units) I (A) I (units) I (A) I (units)

RQ5.LR3 1.96 37.12 162 37.17 175 36.73 55 36.53 0RQ4.LR3 1.86 35.29 295 35.32 303 34.84 163 34.28 0RQ5.LR7 2.00 38.05 114 38.09 125 37.62 38 37.62 0RQ4.LR7 1.97 37.40 171 37.44 182 37.01 65 36.77 0

FIDEL 2008 FIDEL 2009 FIDEL 2010 TIMBER 2010

o In 2008 we had the original FIDEL parameters and they changed slightly in 2009 at injection

o First beta-beating study in 2009 showed a 3% error at injectiono Wrong pre-cycle found in Dec. 2009 and corrected. The required

corrections were reduced to 1.5% (average)o The new FIDEL 2010 (not yet used) predict a stronger residual magnetisation

in agreement with actual currents recorded in TIMBER, i.e. nominal 2009 settings plus trims to decrease the beta-beating

o The new FIDEL 2010 gives no changes at 3.5 TeV (same geometric), i.e. FIDEL 2010 are identical to FIDEL 2009 for this range of E.

Note: I (units) is wrt new 2010 operational currents

over-corrected?

10

I (A) TFL avg (units) TFL sigma (units)

1 -20915 -8262 -10715 -67655 -4323 354

10 -2155 12215 -1416 7120 -992 4827 -704 4240 -437 28

100 -111 13200 0 8312 29 8437 31 11600 -70 17437 138 9200 212 10100 313 1340 611 2710 1730 975 3527 1982 8720 3541 18395 422

MQWB results (magnet 10 and 51 = 4 apertures)

-25000

-20000

-15000

-10000

-5000

0

5000

10000

15000

20000

25000

0 100 200 300 400 500 600

TF

(un

its)

Current (A)

MQWB avg

b

-25000

-20000

-15000

-10000

-5000

0

5000

10000

15000

20000

25000

0 10 20 30 40

TF

(uni

ts)

Current (A)

MQWB avg

b

Zoom on hysteresis

Geo @ 200 A not valid!

BL negative for I < 2.x A!

11

MQWB comparison issueswrt series measurements

MQWB measurement conclusions

o The entire TF is different due to pre-cycle (not only low currents)

o At best the only point from series measurement which could be re-used is at 600 A, but is not justified given the small spread at 600 A in new measurements !

o So assume MQWB 10 + MQWB 51 represent the population and use the same TF for all MQWB !

o Change TF geometric current to 437 A

MQW 51 comparison ( new SSW minus old RC units)

ap1 ap2I b b

200 -87 -93600 -8 -15

12

MQWB FiDeL 2010

I (A) TFL avg (units)

5 -434010 -217915 -144220 -101927 -73340 -467

100 -141200 -31312 -2437 0600 -101

Fit branch where BL>0and dI/dT > 0

-12000

-10000

-8000

-6000

-4000

-2000

0

0 100 200 300 400 500 600M

QW

B 1

0 +

51T

F (u

nits

)

Current (A)

sigma(1) 0.00001932I0(1) 500.71s(1) 140072542.54673900Inomref(1) 600

rho -0.00018512r 1.04013624Iinjref 30

-80

-60

-40

-20

0

20

40

60

80

0 200 400 600

Res

idua

l err

or (u

nits

)

Current (A)

13

MQWB current predictions

CIRCUIT G (T/m)I (A) I (units) I (A) I (units) I (A) I (units) I (A) I (units)

RQT5.L3 11.35 217.98 -1 218.01 0 221.28 150 218.01 0RQT4.L3 8.04 154.49 6 154.39 0 157.35 192 154.39 0RQT4.R3 8.04 154.51 0 154.51 0 157.35 184 154.51 0RQT5.R3 11.35 218.07 -1 218.10 0 221.28 146 218.10 0RQT5.L7 0.38 7.33 1422 6.42 -2 9.50 4796 6.42 0RQT4.L7 3.87 74.52 52 74.13 0 76.82 363 74.13 0RQT4.R7 3.87 74.56 54 74.16 -1 76.82 359 74.16 0RQT5.R7 0.38 7.33 1278 6.50 3 9.50 4614 6.50 0

FIDEL 2008 FIDEL 2009/2010 FIDEL 2010 TIMBER 2010

450 GeV

3.5 TeV

o The new FIDEL 2010 prediction for 450 GeV is better in agreement with actual currents (recorded in TIMBER) to decrease the beta-beating

o We have considerable differences from TIMBER at 3.5 TeV as well (slides 11 gives us 100 units systematic diff at 200 A)

o The worst-cases as usual RQT5.L7 and RQT5.R7 (hardest to predict)

CIRCUIT G (T/m)I (A) I (units) I (A) I (units) I (A) I (units) I (A) I (units)

RQT5.L3 1.46 27.06 -957 27.11 -941 30.24 105 29.93 0RQT4.L3 1.03 18.52 -1400 18.33 -1490 22.04 234 21.54 0

RQT4.R3 1.03 18.53 -1711 18.73 -1621 22.04 -138 22.35 0RQT5.R3 1.46 27.07 -993 27.09 -987 30.24 61 30.06 0RQT5.L7 0.05 0.94 -5105 0.35 -8209 2.11 955 1.93 0RQT4.L7 0.50 9.58 -1960 8.62 -2765 11.74 -152 11.92 0RQT4.R7 0.50 9.59 -679 7.53 -2676 11.74 1411 10.28 0RQT5.R7 0.05 0.94 -5686 0.39 -8201 2.11 -344 2.19 0

FIDEL 2008 FIDEL 2009/1010 FIDEL 2010 TIMBER 2010

Note: I (units) is wrt new 2010 operational currents

over-corrected?

Old FIDEL parameters actually

used

14

Check of beta-beating for MQWB @ 3.5 TeV

o Thanks to Rogelio Tomas Garcia for checking the estimated change of beta- beating using the new MQWB currents

o The change in currents with new FIDEL 2010 versus operation should reduce the beta-beating (slightly)

o The MQWB @ 3.5 TeV is not a strong source for beta-beating; around 3-5%

o The greatest advantage of applying the new FIDEL parameters instead of the trim is that FIDEL is based upon a physical model whilst the trim is a linear function

o Therefore the FIDEL TF should work better during the ramp where no beta-beat measurements exist to improve the trim function, and we know the FIDEL TF is non-linear due to magnetic hysteresis