J.DiMarco 16Nov2010

1

LQS01b Magnetic Measurements Results(preliminary)

J. DiMarco16Nov2010

J.DiMarco 16Nov2010

2

Measurements:

25Aug – cold measurements at VMTF at 5328A (100T/m)14Oct – warm measurements in IB3 at 10A

Probes:25cm long, R=23mm radial probe (VMTF)10cm long, R=23mm radial probe (VMTF)

10cm long, R=21.7mm tangential probe (VMTF)

49cm long circuit board, R=29.4mm (ferret) (warm meas.)

on single circuit boarddisplaced longitudinally

J.DiMarco 16Nov2010

3

‘Ferret_MFM’ system:

59mm diameter probe, rotating inside ~63.5mm outer tube

3 signals: UnBucked (UB), Dipole Bucked (DB), and Dipole+Quad Bucked (DQB)

Labview data acquisition applicationMatlab analysis code

Measurements:

LQS01b measurements 10/14

4Hz rotation rate with external flex shaft, sampling at 40kHz with NI-4472b (DSA) (ADC) card. 10A magnet current ( gradient ~ 0.185 T/m 5mT at UB radius 1 unit of harmonics is ~0.5T)

6 channels of input (Index, Encoder, UB/DB/DQB probe signals, current) (gravity sensor not recorded)

Measurements every 0.25m (probe length ~0.5m)

On board amplifier has gains 10/1000/1000 for UB/DB/DQB respectively.

J.DiMarco 16Nov2010

4

Ferret probe for warm measurements

J.DiMarco 16Nov2010

5

Ferret system has only recently (Fall 2010) been assembled…

measurement of LQS01b was the ferret system‘commissioning’ !

…presentation reflects state of the system as well as magnet

J.DiMarco 16Nov2010

6

LQS01b dataat z=0 position

warm measurement(weak field ~5mT quad)

UB Signal

DQB Signal

Raw ferret data at 10A

J.DiMarco 16Nov2010

7

Probes used for cold (VMTF) measurements

10 and 25cm circuit board (radial) probes

10cm Tan Probe

J.DiMarco 16Nov2010

8

Some caveats in comparing warm/cold data:

1) The lengths of the probe used in VMTF and in warm meas. are different – 25/10cm and ~50cm respectively

2) Probe diameters are different - 46mm VMTF and 59mm IB3 - this accounts for the larger error bars in high harmonics of the cold data (taken at low gain).

3) The dipole-bucked (DB) winding of the probe in the warm measurements (ferret) was saturating the datacq, and could not be used for the absolute quad strength of the warm data (the strength is given from the un-bucked (UB) signal at the nominal radius (which should be reasonably close however))

4) Z-positioning in warm data was very approximate (the probe had a very tight fit in the pipe and moving it disturbed the position of the pipe, etc.) - warm positions may be off by 2cm+. Z-positions in the cold data were not well matched between probes.

5) The leads position was different as configured vertically in the dewar compared to IB3. Data near end may have some effects from this.

J.DiMarco 16Nov2010

9

Error bars are statistics (sd) only

Probe centering offsets are large, 4-6mm in both warm and cold data (first order correction only has been applied)

Harmonics reported at reference radius of 30mm

Also note….

J.DiMarco 16Nov2010

10

J.DiMarco 16Nov2010

11

J.DiMarco 16Nov2010

12

J.DiMarco 16Nov2010

13

J.DiMarco 16Nov2010

14

J.DiMarco 16Nov2010

15

J.DiMarco 16Nov2010

16

J.DiMarco 16Nov2010

17

J.DiMarco 16Nov2010

18

J.DiMarco 16Nov2010

19

J.DiMarco 16Nov2010

20

J.DiMarco 16Nov2010

21

J.DiMarco 16Nov2010

22

J.DiMarco 16Nov2010

23

J.DiMarco 16Nov2010

24

J.DiMarco 16Nov2010

25

J.DiMarco 16Nov2010

26

J.DiMarco 16Nov2010

27

J.DiMarco 16Nov2010

28

J.DiMarco 16Nov2010

29

J.DiMarco 16Nov2010

30

Conclusions:

Reasonable agreement was obtained among the cold measurements with the various probes

Warm scan also agrees fairly well, but there are some significant differences in quadrupole strength and longitudinal features of sextupole component

More work needed to understand/gain confidence in probe measurements:continued development, bench testing, inter-calibrations are planned

LQS01b has large b4/a4 and b6 harmonics. Some other harmonics also seem to show significant variation as a function of z-position (b3, a3, a5).