Results with ISCOOL a new Radio Frequency Quadrupole Cooler and - - PowerPoint PPT Presentation

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Results with ISCOOL a new Radio Frequency Quadrupole Cooler and - - PowerPoint PPT Presentation

Jun 28, 2023 102 likes •323 views

Results with ISCOOL a new Radio Frequency Quadrupole Cooler and Buncher at ISOLDE P. Delahaye, H. Frnberg, AB-OP-PSB, ISCOOL, COLLAPS, ISOLDE collaboration ISOLDE WS 2007 Where at ISOLDE ISCOOL ISOLDE WS 2007 Installation in pictures

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SLIDE 1

ISOLDE WS 2007

Results with ISCOOL a new Radio Frequency Quadrupole Cooler and Buncher at ISOLDE

  • P. Delahaye,
  • H. Frånberg,

AB-OP-PSB, ISCOOL, COLLAPS, ISOLDE collaboration

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SLIDE 2

ISOLDE WS 2007 ISCOOL

Where at ISOLDE

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SLIDE 3

ISOLDE WS 2007

Installation in pictures

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SLIDE 4

ISOLDE WS 2007

INSTALLATION

Implementation of the RFQ into the ISOLDE vacuum system. Construction of HV platform and HV cage of the RFQ. Standard controls in the working sets: QP arrays for the RFQ and for the beam tuning after the cooler.

– RF and gas still on LabVIEW.

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SLIDE 5

ISOLDE WS 2007

OPERATION OF ISCOOL

  • Set-up by the ISOLDE operators.
  • Improved transmission past the switchyard

Improved (faster and easier) set-up for the beam to the experiments

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SLIDE 6

ISOLDE WS 2007

Principle

RF

V

Three elements: RF quadrupolar field Radial confinement DC potentials Extracting ion in bunches or in continuous mode Buffer gas Ion motion cooling

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SLIDE 7

ISOLDE WS 2007

Transmissions

  • Potentials along the axis

Transmission dependence on the emittance of the ISOLDE ion sources.

ISOLDE on-line surface ion sources has smaller emittance than ISOLDE FEBIAD ion sources (<25 π·mm mrad). The off-line tests were performed with an ion source with ε = 35π mm mrad 80eV 5-2V/cm ~1E-2 mbar 4He 10-2mbar l/s EXTRACTION INJECTION 50V (30V enough) TRAPPING

20 40 60 80 100 120 140 20 40 60 80 100 Mass Transmission

  • n-line surface ionsource
  • n-line plasma ionsource
  • ff-line surface ionsource
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SLIDE 8

ISOLDE WS 2007

Bunching mode

30-60 keV 80eV 5-2V/cm ~1E-2 mbar 4He 10-2mbar l/s EXTRACTION INJECTION 50V (30V enough) TRAPPING

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SLIDE 9

ISOLDE WS 2007

Cooling time

  • TOF < 1ms from the

entrance to the exit of the RFQ

– No losses for short lived ions.

  • 1 passage is enough

to get a cold beam

– as measured off-line, and other labs as predicted by simulations for other systems

  • 200

200 400 600 800 1000 1200 1400 1600 1800

  • 1

1 2 3 4 4.0x10

  • 4

6.0x10

  • 4

8.0x10

  • 4

1.0x10

  • 3

1.2x10

  • 3

1.4x10

  • 3

1.6x10

  • 3

Beam gate Time [μs] MCP

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SLIDE 10

ISOLDE WS 2007

Emittance measurements (off-line)

~35π·mm·mrad 95% emittance ~2.2π·mm·mrad 95% emittance

  • 10 x decrease of the

beam emittance

– The worst case scenario at ISOLDE is the FEBIAD ion source with >25 p·mm·mrad emmittance.

  • Injection efficiency into

the cooler is depending

  • n the beam emittance

from the ISOLDE target and ion source unit.

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SLIDE 11

ISOLDE WS 2007

0.00E+000 4.00E+008 8.00E+008 1.20E+009

  • 2.00E+007

0.00E+000 2.00E+007 4.00E+007 6.00E+007 8.00E+007 1.00E+008 1.20E+008 1.40E+008 1.60E+008

Extracted ions Injected ions

Space charge limits

  • Up to 108/s!! As

measured with FC (data under analysis with MCP)

1x10

9

2x10

9

3x10

9

4x10

9

5x10

9

0.0 2.0x10

7

4.0x10

7

6.0x10

7

8.0x10

7

1.0x10

8

1.2x10

8

1.4x10

8

Extracted ions Injected ions

39K,

Collection time=10 ms–1 sec Extraction time 150 us

85Rb

0.0 5.0x10

7

1.0x10

8

1.5x10

8

2.0x10

8

2.5x10

8

0.0 2.0x10

6

4.0x10

6

6.0x10

6

8.0x10

6

1.0x10

7

1.2x10

7

1.4x10

7

Extracted ions Injected ions

23Na

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SLIDE 12

ISOLDE WS 2007

Bunch width

Depends on the space charge and cooling time

  • 40 -20

20 40 60 80 100 120 140

  • 8x10
  • 3
  • 7x10
  • 3
  • 6x10
  • 3
  • 5x10
  • 3
  • 4x10
  • 3
  • 3x10
  • 3
  • 2x10
  • 3
  • 1x10
  • 3

1x10

  • 3

2x10

  • 3

MCP signal Time [μs]

10 ms 100 ms 1000 ms

Collection time=cooling time

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SLIDE 13

ISOLDE WS 2007

Yield measurements

  • 26Na T1/2=1.07 s
  • 48K T1/2=6.8 s
  • Yields in continuous mode:

– 26Na :1.2e6 at/uC – 48K: 2.2e4 at/uC

  • Yields in bunched mode

– analysis under progress

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SLIDE 14

ISOLDE WS 2007

HOT SPOTS

0.5 µSv/h 15 µSv/h 10 µSv/h 3 µSv/h 10 µSv/h 15 µSv/h 5 µSv/h 5 µSv/h 0.5 µSv/h Beam direction

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SLIDE 15

ISOLDE WS 2007

Results

  • High transmission efficiencies
  • Easy beam tuning to experiments
  • Yield measurements continuous vs. bunched

mode

  • Losses due to trapping time (analysis in

progress

  • First measurements with radioactive isotopes

performed together with COLLAPS (see next talk)

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SLIDE 16

ISOLDE WS 2007

ISOLDE HRS + Cooled beams

HRS ISCOOL

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SLIDE 17

ISOLDE WS 2007

Outlook

Up to October 2007: From

  • Nov. 2007:

Next step: Upgrade of HRS Mag 90: EURISOL HIE Isolde:

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SLIDE 18

ISOLDE WS 2007

Thanks to:

  • AB-OP-PSB-iso

team: Pascal, Erwin, Magnus, Emiliano and Tim.

  • AB/ATB
  • AB/CO
  • AB/PO
  • AB/VAC
  • SC/RP
  • ISOLDE

collaboration

  • COLLAPS

collaboration

  • ISCOOL

collaboration

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SLIDE 19

ISOLDE WS 2007

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SLIDE 20

ISOLDE WS 2007

ISCOOL tests with COLLAPS

46K Beam 1E5 ions/s after the cooler.

Collection time 20 minutes, with 300ms bunching and a 12us gate and 2mW of laser power.

  • 7
  • 6
  • 5
  • 4
  • 3
  • 2
  • 1

20 40 60 80 100 120 140 160 180 200

Gated counts Tuning voltage

  • 7
  • 6
  • 5
  • 4
  • 3
  • 2
  • 1

490000 492000 494000 496000 498000 500000 502000

Total counts Tuning volts

Singles (continuous counting) Bunched:12us gated spectra

Background suppression factor~1E4