1 APC: October 3, 2008 Mike Barnes, AB/BT

Effect of 25ns, 50ns & 75ns Effect of 25ns, 50ns & 75ns Beam Bunch Spacing upon Beam Bunch Spacing upon

MKDV Kickers: MKDV Kickers: MD August 12MD August 12thth to 14 to 14thth, 2008, 2008

M.J. BARNES, AB/BT

Also on behalf of V. Senaj & L. Ducimetière

2 APC: October 3, 2008 Mike Barnes, AB/BT

II. Principle of Beam DumpingPrinciple of Beam Dumping

When the beam cannot be extracted: dumping of the beam using the MKD beam dump system (MD, emergencies...)

Function of the kicker magnets: Sweep the beam to distribute the beam

energy over a large volume of the absorbed block.

MKDV1: V=56mm, H=75mm, 5cells each ~51cmMKDV2: V=56mm, H=83mm , 5cells each ~51cm

MKDH1: V=56mm, H=96mm MKDH2: V=56mm, H=83mm MKDH3: V=60mm, H=105mm

H (vap)

H (hap)

V (vap)

V (hap)

3 APC: October 3, 2008 Mike Barnes, AB/BT

MKDV Temperature & Pressure on 12, MKDV Temperature & Pressure on 12, 13 & 1413 & 14thth August 2008 August 2008

0.0E+00

5.0E-08

1.0E-07

1.5E-07

2.0E-07

2.5E-07

3.0E-07

3.5E-07

4.0E-07

4.5E-07

5.0E-07

12-08-08 0:00

12-08-08 6:00

12-08-08 12:00

12-08-08 18:00

13-08-08 0:00

13-08-08 6:00

13-08-08 12:00

13-08-08 18:00

14-08-08 0:00

14-08-08 6:00

14-08-08 12:00

14-08-08 18:00

15-08-08 0:00

Date & Time

Pres

sure

(mba

r)

26

28

30

32

34

36

38

40

42

44

46

Tem

pera

ture

(C)

MKDV1: pressureMKDV2: pressureMKDV1: TemperatureMKDV2: Temperature

25ns beam

3 batches 50ns beam @ 01:43:immediate trip

50ns beam 05:13 to 07:00

75ns beam to 01:30

Normally: MKDV1 temperature>MKDV2 and pressure < 6e-8 mbar (as per 25ns beam);

For 75ns beam MKDV2 temperature > MKDV1 and pressure < 6e-8 mbar;

For 50ns beam MKDV temperature is not an issue, but pressure is an issue!.

8s resolution for pressure.

See slides 6, 7 & 8

8s resolution

4 APC: October 3, 2008 Mike Barnes, AB/BT

MKDVMKDV No measures taken to reduce beam

coupling impedance to ferrite; No transition pieces, between magnet

tank and magnet frame, installed in LSS1 (now installed in spare MKDV1 magnet) ~16cm gap at each end.

1 cell

MKE magnet:

5 APC: October 3, 2008 Mike Barnes, AB/BT

0

50

100

150

200

250

300

350

400

450

500

200

220

240

260

280

300

320

340

360

380

400

420

440

460

480

500

Frequency (MHz)

Rea

l Im

peda

nce

(Ohm

s/m

)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Nor

mal

ized

Bea

m S

pect

rum

A

mpl

itude

MKDV1: Real Longitudinal Impedance (Measured)

75ns bunch spacing: normalized

MKDV: Longitudinal ImpedanceMKDV: Longitudinal Impedance

050

100150200

250300350400

450500550

600650

0 100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

Frequency (MHz)

Rea

l Im

peda

nce

(Ohm

s/m

)

MKDV1: Real Longitudinal Impedance (Measured)MKDV1: Real Longitudinal Impedance (Theoretical)MKDV2: Real Longitudinal Impedance (Theoretical)

•Longitudinal Impedance (ZRL) Theoretical Calculation: CERN-SL-2000-04 AP, by H. Tsutsui, pp7-10.•MKDV1 theoretical ZRL fits baseline of measurement reasonably well.•Cell length of 51cm (λ/4) resonance, for open circuit, of 147MHz (assuming μr & εr of 1).•“Spikes” may also be due to lack of transition pieces??

11.5MHz

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0E+00

5.0E+07

1.0E+08

1.5E+08

2.0E+08

2.5E+08

3.0E+08

3.5E+08

4.0E+08

4.5E+08

5.0E+08

Frequency (Hz)

Nor

mal

ized

SPS

Bea

m S

pect

rum 25ns bunch spacing: normalized mag.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0E+00

5.0E+07

1.0E+08

1.5E+08

2.0E+08

2.5E+08

3.0E+08

3.5E+08

4.0E+08

4.5E+08

5.0E+08

Frequency (Hz)

Nor

mal

ized

SPS

Bea

m S

pect

rum 50ns bunch spacing: normalized mag.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0E+00

5.0E+07

1.0E+08

1.5E+08

2.0E+08

2.5E+08

3.0E+08

3.5E+08

4.0E+08

4.5E+08

5.0E+08

Frequency (Hz)

Nor

mal

ized

SPS

Bea

m S

pect

rum 75ns bunch spacing: normalized mag.

Courtesy of Giulia Papotti:All bunch spacing hit: ~440.6MHz and ~480.7MHz ZRL

Amplitude is already low at 500MHz.

25ns bunch spacing.~40.05MHz spacing of lines

50ns bunch spacing.~20.03MHz spacing of linesAlso hits: 420.6MHz and 460.6MHz ZRL

75ns bunch spacing.~13.5MHz spacing of linesAlso hits: 334.0MHz and 387.1MHz ZRL

6 APC: October 3, 2008 Mike Barnes, AB/BT

MKDV Pressure on 14/08/2008, MKDV Pressure on 14/08/2008, between 01:20hrs & 02:10hrs.between 01:20hrs & 02:10hrs.

0.00E+00

1.00E-07

2.00E-07

3.00E-07

4.00E-07

5.00E-07

6.00E-07

7.00E-07

8.00E-07

9.00E-07

1.00E-06

14-08-08 1:20

14-08-08 1:25

14-08-08 1:30

14-08-08 1:35

14-08-08 1:40

14-08-08 1:45

14-08-08 1:50

14-08-08 1:55

14-08-08 2:00

14-08-08 2:05

14-08-08 2:10

Date & Time

Pres

sure

(mba

r)

26

28

30

32

34

36

38

40

42

44

46

Tem

pera

ture

(C)MKDV1: pressure

MKDV2: pressureMKDV1: TemperatureMKDV2: Temperature

75ns beam to ~01:30

Started 1 batch 50ns beam at 1:32hrs,

continuously.

Single shot of 4 batches of 50ns beam at 2:05hrs: interlock.

One shot of 2 batches of 50ns beam at

1:42hrs.

One shot of 3 batches of 50ns beam at

1:43hrs: interlock.

Information from: Giulia Papotti:

Summary: 50ns beam causes pressure rise; high pressure with 3 or 4 batches per shot.

1s resolution

7 APC: October 3, 2008 Mike Barnes, AB/BT

MKDV Pressure on 14/08/2008, MKDV Pressure on 14/08/2008, between 05:00hrs & 07:00hrs.between 05:00hrs & 07:00hrs.

0.0E+00

1.0E-07

2.0E-07

3.0E-07

4.0E-07

5.0E-07

6.0E-07

7.0E-07

8.0E-07

9.0E-07

14-08-08 5:00

14-08-08 5:10

14-08-08 5:20

14-08-08 5:30

14-08-08 5:40

14-08-08 5:50

14-08-08 6:00

14-08-08 6:10

14-08-08 6:20

14-08-08 6:30

14-08-08 6:40

14-08-08 6:50

14-08-08 7:00

Date & Time

Pres

sure

(mba

r)

26

27

28

29

30

31

32

33

34

35

Tem

pera

ture

(C)

MKDV1: pressureMKDV2: pressureMKDV1: TemperatureMKDV2: Temperature

Started 1 batch 50ns beam at 5:13hrs.

One shot of 3 batches of 50ns beam at

5:39hrs.

Four shots of 4 batches of 50ns beam at 5:41hrs: interlock.

Four shots of 4 batches of 50ns beam

at 5:45hrs.

Two shots of 4 batches of 50ns beam

at 5:49hrs.

Information from: Giulia Papotti:

See next slide

One batch per shot of 50ns beam from

6:05hrs to 7:00hrs.

Summary: 50ns beam causes pressure rise; high pressure with 3 or 4 batches per shot.

1s resolution

8 APC: October 3, 2008 Mike Barnes, AB/BT

MKDV Pressure on 14/08/2008, MKDV Pressure on 14/08/2008, between 05:49hrs & 05:50hrs.between 05:49hrs & 05:50hrs.

0.00E+00

1.00E-07

2.00E-07

3.00E-07

4.00E-07

5.00E-07

6.00E-07

7.00E-07

8.00E-07

9.00E-07

14-08-08 5:49:30

14-08-08 5:49:35

14-08-08 5:49:40

14-08-08 5:49:45

14-08-08 5:49:50

14-08-08 5:49:55

14-08-08 5:50:00

14-08-08 5:50:05

14-08-08 5:50:10

14-08-08 5:50:15

14-08-08 5:50:20

Date & Time

Pres

sure

(mba

r)

26

27

28

29

30

31

32

33

34

35

Tem

pera

ture

(C)

MKDV1: pressureMKDV2: pressureMKDV1: TemperatureMKDV2: Temperature

Limited (1s) resolution for pressure;May miss peaks on graph (interlock requires few 10’s of ms);Fast pressure rise and fall due to surface effect (e.g. electron cloud), or gauge misreading??

Two shots of 4 batches of 50ns beam

at 5:49hrs??

9 APC: October 3, 2008 Mike Barnes, AB/BT

47MHz

Misc. Longitudinal ImpedanceMisc. Longitudinal Impedance

MKI: 15 screen conductors

MKDV1: no beam screen or transition pieces. Spikes due to cell length ???

MKE (L10): stripes on all cells

MKE: no stripes

MKE (S6): stripes on 2 of 7 cells

For MKE: Is frequency of onset of spikes

dependent upon aperture size? e.g. (MKE-L9 & MKE-S3) ;

Serigraphy generally eliminates spikes up to and beyond 500MHz.

MKI: no screen

Apertures (hap x vap):• MKE-L: 147.7 x 35mm;• MKE-S: 135 x 32mm;• MKI: 54 x 54mm;• MKDV1: 56 x 75mm. Cell Length:• MKE: ~24cm;• MKDV1: ~51cm.

(Note: impedance data in following plot is scaled according to length of tank rather than magnet length; therefore actual impedance per metre is larger than shown in plot)

10 APC: October 3, 2008 Mike Barnes, AB/BT

SPS Kickers: Vacuum, August SPS Kickers: Vacuum, August 14, 200814, 2008

August 14, 2008

0.0E+00

1.0E-07

2.0E-07

3.0E-07

4.0E-07

5.0E-07

6.0E-07

7.0E-07

8.0E-07

9.0E-07

1.0E-06

0:000:30

1:001:30

2:002:30

3:003:30

4:004:30

5:005:30

6:006:30

7:00

Time

Pres

sure

(mba

r)

MKDV1

MKDV2

August 14, 2008

0.0E+00

1.0E-08

2.0E-08

3.0E-08

4.0E-08

5.0E-08

6.0E-08

7.0E-08

8.0E-08

9.0E-08

1.0E-07

0:301:00

1:302:00

2:303:00

3:304:00

4:305:00

5:306:00

6:307:00

Time

Pres

sure

(mba

r)

MKDH1

MKDH2

MKDH3

MKE6: August 14, 2008

0.0E+00

5.0E-08

1.0E-07

1.5E-07

2.0E-07

2.5E-07

3.0E-07

3.5E-07

4.0E-07

0:000:30

1:001:30

2:002:30

3:003:30

4:004:30

5:005:30

6:006:30

7:00

Time

Pres

sure

(mba

r)

MKE1 (serigraphed)

MKE2 (No cells serigraphed)

MKE3 (2 cells serigraphed)

SPS MKQ: 14th August 2008

1.0E-09

5.1E-08

1.0E-07

1.5E-07

2.0E-07

2.5E-07

0:000:30

1:001:30

2:002:30

3:003:30

4:004:30

5:005:30

6:006:30

7:00

Time

Pres

sure

(mba

r)

MKQH (ceramic substrate for impedance reduction)

MKQV

75ns beam

75ns beam

75ns beam

75ns beam

3 batches, 50ns 4 batches, 50ns

3 batches, 50ns 4 batches, 50ns

4 batches, 50ns4 batches, 50ns3 batches, 50ns

3 batches, 50ns

4x4 batches, 50ns

4x4 batches, 50ns

4x4 batches, 50ns

4x4 batches, 50ns

50ns beam

50ns beam

50ns beam

50ns beam

MKDV1: hap=56mm, vap=75mmMKDV2: hap=56mm, vap=83mm

MKDH1: hap=96mm, vap=56mmMKDH2: hap=96mm, vap=56mmMKDH3: hap=105mm, vap=60mm

MKE1: hap=147.7mm, vap=35mmMKE2: hap=147.7mm, vap=35mmMKE3: hap=135mm, vap=32mm

MKQH: hap=135mm, vap=33.9mmMKQV: hap=56mm, vap=102mm

Transition pieces Ferrite

No transition piecesFerrite

No transition pieces.0.35mm laminated steelNo temperature probes.

MKQH less sensitive to 50ns & more sensitive to 75 bunch spacing….No temperature probes.

1s resolution

11 APC: October 3, 2008 Mike Barnes, AB/BT

SPS Kickers: Vacuum, August SPS Kickers: Vacuum, August 14, 200814, 2008

August 14, 2008

0.0E+00

1.0E-07

2.0E-07

3.0E-07

4.0E-07

5.0E-07

6.0E-07

7.0E-07

8.0E-07

9.0E-07

1.0E-06

0:000:30

1:001:30

2:002:30

3:003:30

4:004:30

5:005:30

6:006:30

7:00

Time

Pres

sure

(mba

r)

MKDV1

MKDV2

0.0E+00

2.0E-09

4.0E-09

6.0E-09

8.0E-09

1.0E-08

1.2E-08

1.4E-08

1.6E-08

1.8E-08

2.0E-08

0:000:30

1:001:30

2:002:30

3:003:30

4:004:30

5:005:30

6:006:30

7:00

Time

Pres

sure

(mba

r)

MKP4MKP3MKP2MKP1

75ns beam

75ns beam

3 batches, 50ns 4 batches, 50ns

4 batches, 50ns

3 batches, 50ns

4x4 batches, 50ns

4x4 batches, 50ns

50ns beam

50ns beam

MKDV1: hap=56mm, vap=75mmMKDV2: hap=56mm, vap=83mm

12xMKP-S: hap=101mm, vap=61mm4xMKP-L: hap=141mm, vap=54mm

No transition piecesFerrite

0.00E+00

1.00E-08

2.00E-08

3.00E-08

4.00E-08

5.00E-08

6.00E-08

7.00E-08

8.00E-08

9.00E-08

Time

Pre

ssur

e (m

bar)

MKE1MKE2MKE3MKE4MKE5

75ns beam

3 batches, 50ns4 batches, 50ns 4x4 batches, 50ns

50ns beam

MKE1: hap=147.7mm, vap=35mmMKE2: hap=147.7mm, vap=35mmMKE3: hap=135mm, vap=32mmMKE4: hap=135mm, vap=32mmMKE5: hap=147.7mm, vap=35mm

Transition pieces

MKE4

1s resolution

12 APC: October 3, 2008 Mike Barnes, AB/BT

26

2830

3234

36

3840

4244

46

Date & Time

Tem

pera

ture

(C)

MKDV1 (temperature)

MKDV2 (temperatue)

20

25

30

35

40

45

50

55

60

65

Date & Time

Tem

pera

ture

(C)

MKE1A (serigraphed)MKE1B (serigraphed)MKE2A (no serigraphy)MKE2B (no serigraphy)MKE3A (2 cells serigraphed)MKE3B (2 cells serigraphed)TunnelMKE6 temp. not overly sensitive

to 50ns or 75 bunch spacing.

SPS Kickers: Temperature, SPS Kickers: Temperature, August 12-14, 2008August 12-14, 2008

2628303234363840424446

Date & Time

Tem

pera

ture

(C)

MKDV1 (temperature)

MKDV2 (temperatue)

20

25

30

35

40

45

50

55

60

65

Date & Time

Tem

pera

ture

(C)

MKE1A (serigraphed)MKE1B (serigraphed)MKE2A (no s erigraphy)MKE2B (no serigraphy)MKE3A (2 cells serigraphed)MKE3B (2 cells serigraphed)Tunnel

MKE6: 25ns beam

MKDV: 25ns beam MKDV: 75ns beam to 01:30hrs, 50ns beam 05:13 to 07:00

MKE6: 75ns beam to 01:30hrs, 50ns beam 05:13 to 07:00

25ns beam

25ns beam

75ns beam

75ns beam

50ns beam

50ns beam

MKE6 temperature rise limited by serigraphy.

13 APC: October 3, 2008 Mike Barnes, AB/BT

SPS Kickers: Temperature, SPS Kickers: Temperature, August 12-14, 2008August 12-14, 2008

26

2728

2930

3132

33

3435

3637

38

13/08/2008 20:00

13/08/2008 21:00

13/08/2008 22:00

13/08/2008 23:00

14/08/2008 0:00

14/08/2008 1:00

14/08/2008 2:00

14/08/2008 3:00

14/08/2008 4:00

14/08/2008 5:00

14/08/2008 6:00

14/08/2008 7:00

14/08/2008 8:00

14/08/2008 9:00

14/08/2008 10:00

Date & Time

Tem

pera

ture

MKP1

MKP2

Tunnel

20

25

30

35

40

45

50

55

60

65

70

13/08/2008 20:00

13/08/2008 21:00

13/08/2008 22:00

13/08/2008 23:00

14/08/2008 0:00

14/08/2008 1:00

14/08/2008 2:00

14/08/2008 3:00

14/08/2008 4:00

14/08/2008 5:00

14/08/2008 6:00

14/08/2008 7:00

14/08/2008 8:00

14/08/2008 9:00

14/08/2008 10:00

Date & Time

Tem

pera

ture

(C)

MKE1aMKE1BMKE2AMKE2BMKE3AMKE3BMKE4AMLE4BMKE5AMKE5BTunnel

26

2728

2930

3132

33

3435

3637

38

12/08/2008 12:00

12/08/2008 14:00

12/08/2008 16:00

12/08/2008 18:00

12/08/2008 20:00

12/08/2008 22:00

13/08/2008 0:00

13/08/2008 2:00

13/08/2008 4:00

13/08/2008 6:00

13/08/2008 8:00

13/08/2008 10:00

13/08/2008 12:00

Date & Time

Tem

pera

ture

MKP1

MKP2

Tunnel

20

25

30

35

40

45

50

55

60

65

70

12/08/2008 12:00

12/08/2008 14:00

12/08/2008 16:00

12/08/2008 18:00

12/08/2008 20:00

12/08/2008 22:00

13/08/2008 0:00

13/08/2008 2:00

13/08/2008 4:00

13/08/2008 6:00

13/08/2008 8:00

13/08/2008 10:00

13/08/2008 12:00

Date & Time

Tem

pera

ture

(C)

MKE1aMKE1BMKE2AMKE2BMKE3AMKE3BMKE4AMLE4BMKE5AMKE5BTunnel

MKE4: 25ns beam

MKP: 25ns beam MKP: 75ns beam to 01:30hrs, 50ns beam 05:13 to 07:00

MKE4: 75ns beam to 01:30hrs, 50ns beam 05:13 to 07:00

25ns beam

25ns beam

75ns beam

75ns beam

50ns beam

50ns beam

MKE4 temp. not overly sensitive to 50ns or 75 bunch spacing.

MKP temp. not overly sensitive to 50ns or 75 bunch spacing.

MKP temperature probes both on one magnet.

14 APC: October 3, 2008 Mike Barnes, AB/BT

Summary & Future PlansSummary & Future Plans “Spikes” on measured MKDV1 longitudinal impedance, which are not present

in analytical calculation, are probably attributable to magnet cell length, aperture dimensions and absence of transition pieces.

An MKDV1 magnet is presently being HV conditioned (it has transition pieces). It is planned to make longitudinal impedance measurements on this magnet before installation (during the next shutdown); this will allow effect of transition pieces to be assessed.

Impedance resonances of MKDV2 (not measured) probably cause heating of ferrite with 75ns bunch spacing.

Shielding of MKE magnets eliminated high impedance resonances in longitudinal impedance and thus significantly reduces heating – possible long-term solution for MKDV1 ?? (MKDV2 no-spare exists, so difficult to modify). Could MKDV1 (H=75mm) be used in place of MKDV2 (H=83mm)?. But still see pressure rise with 50ns bunch spacing…..

50ns bunch spacing causes immediate pressure rise (surface effect-e.g. electron cloud) for both MKDV1 & MKDV2 – but MKDV1 is more significant.

MKE6, MKDH, MKDH & MKQV kickers all show immediate pressure rise with 50ns bunch spacing ….. But MKQH sensitive to 75ns bunch spacing…

Further MD with 50ns beam to confirm, with 3 or 4 batches per shot, as cause of high pressure rise?; electron cloud investigations ????.

Log ion pump current?

15 APC: October 3, 2008 Mike Barnes, AB/BT

Questions & CommentsQuestions & Comments

16 APC: October 3, 2008 Mike Barnes, AB/BT

MKDH3 Longitudinal MKDH3 Longitudinal Impedance MeasurementsImpedance Measurements

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0.0E+00

2.0E+08

4.0E+08

6.0E+08

8.0E+08

1.0E+09

1.2E+09

1.4E+09

1.6E+09

1.8E+09

2.0E+09

Frequency (Hz)

MKD

H3 R

eal L

ongi

tudi

nal I

mpe

danc

e (O

hms/

m)

Improved Log Formula

Theoretical Real Impedance

0

500

1000

1500

2000

2500

3000

0 200

400

600

800

1000

1200

1400

1600

1800

2000

Frequency (MHz)

Rea

l Lon

gitu

dina

l Im

peda

nce

(Ohm

s/m

)

MKE: L10 (fully serigraphed)MKE: L9 (no shielding)MKE: L8 (no shielding)MKE: S3 (no shielding)MKE: S6 (2 of 7 cells serigraphed)MKI43a: 15 screen conductorsMKDV1 (no shielding or transitions)MKDH3 (no shielding or transitions)

• No temperature Probes on MKDH magnets;

• MKDH3 length=1.256m λ/4 resonance of ~60MHz;

• Transverse impedance measurements planned for MKDH3.

MKDH3 no shielding or transition pieces.

17 APC: October 3, 2008 Mike Barnes, AB/BT

MKE: Beam Coupling MKE: Beam Coupling Impedance ReductionImpedance Reduction

Beam coupling impedance is reduced using conductive stripes (serigraphy), i.e. interleaved comb structure, directly printed onto the ferrite blocks and a reliable contact to the metallic HV plates at either side;

Capacitive coupling between stripes (stripes carry beam image current).

Printed strips in MKE-L10

Interdigital comb structure 20mm spacing

surface discharge