E. Beebe LEBT & Ion Injection EBIS Project Technical Review 1/27/2005 LEBT and External Ion...

E. BeebeLEBT & Ion Injection

EBIS Project Technical Review1/27/2005

LEBT and External Ion Injection

Ed Beebe

Preinjector GroupCollider-Accelerator Department



LEBT Requirements

1. Transport of EBIS highly charged ions to RFQExtraction (EBIS-RFQ) up to 10mA, ~100kV

2. Injection of seed ions into EBIS from External Ions Sources Injection (into EBIS) ~10-100A, ~20kV

3. Direct injection to RFQ from additional source (deuterons)

4. Fast Switching between injection & extraction (~1ms for EBIS tuning)

5. Pulse to pulse ion species change (5 Hz)

6. Diagnostics for injected and extracted beamsTime-of-Flight spectrometers for charge state verification

Current Transformers & Faraday CupsBeam Profile monitors



LEBT Layout showing External Ion Injectors and HV Platforms

EBIS Platform is at ground during Ion Injection and confinement; at 100kV during extraction

EBIS HV Platform

(100kV nominal during extraction)

External Ion Source Platform(s)(nom. 20kV)



Schematic of Ion Injection and Extraction from the RHIC EBIS

LEVA

HCIS

TOF

RFQEBIS

Cu +

Au 2+

d+

Au 2+ Cu +

Au 32+, Cu 11+ Au 32+,Cu 11+

d + SOURCE

d +



EBIS operation on HV Platform

RHIC EBIS will require ion beam transport at 17 keV/amu. The EBIS and LEBT are designed so that all EBIS operation can be attained at laboratory ground with the HV platform necessary only for efficient transport of the fast-extracted EBIS ion Beam.

Initial tuning and verification of the EBIS extracted ion beam content will be performed with the EBIS platform at ground and normal (i.e., slower) extraction in order to use the TOF spectrometers effectively.



EBIS operation with Pulsed High Voltage Platform

EBIS BEAM TO RFQ

ION INJECTIONION TRAPPING

PLATFORM BIASHIGH VOLTAGE

During injection and confinement the RHIC EBIS will operate at ground potential --- same as usual operation for the TestEBIS

Just before ion extraction the EBIS Platform Voltage will be applied such that the Ions are extracted through 100kV (nominal) to attain the ~17keV/amu needed for acceleration by the RFQ



Electrical Schematic of EBIS Platforms



Low Energy Vacuum Arc Source (LEVA)

Hollow Cathode Ion Source (HCIS)

External Sources used for Primary Ion Injection

A commercial source, Chordis, used at the Stockholm EBIS at the CRYRING facility, is also under consideration for procurement.



Hollow Cathode source and beamline showing pumping and ion optics

P~4x 10-8 mb P~4x 10-6 mb P~8x 10-5 mb P~0.8mB

•Cu+1 >25A, Ne >80A

•PEBIS~2x10-10 mb for PHCIS~1mb, 10ms, 1Hz shutter operation



Schematic of Hollow Cathode Source power supply configuration



LEBT (hardware view)

Electron collector

Accelerating tube

Electrostatic deflectors

Removable ion beam chopper

Gridded lens

10" gate valve

Electrostatic benders

Mamyrin TOFspectrometer

Magnet lens

Emittance meter

Current transformerInjection into RFQ from proton source

External injection into EBIS from axilliary ion source

Electrostatic bender

Beam switching in the injection line and LEBT is made in electrostatic bender switchyards



EBIS Ion Extraction Region

The EBIS electrostatic lens and acceleration gap form the first major focusing element of the LEBT (EBIS to RFQ beamline)

(A focusing solenoid is used directly before the RFQ after the LEBT electrostatic switchyard which directs injected and extracted beams)

Bellow

Perforated drift tube

8" Gate valve

Ion extractor

Electron repeller

Electron reflector

Ø0.66

Ø1.85

Ø11

.81

Water cooling channel

Lens electrode

Magnet shield

EC bucking coil

Ceramic break

100 kV accelerating tube

9.74

EBIS Diagnostics Layout

Electrostatic Switching

Electrostatic switching is used throughout the EBIS complex since it provides fast response (~1ms) which is important for EBIS tuning using short confinement times after ion injection.

EBIS ion confinement times ~10-100ms during beam delivery and ppm

requirements of 5Hz are less stringent.

•The controller coordinates the application of all time dependent voltages and timing references associated with EBIS operation with a time resolution of 1 s, such as:

•Time dependent ion trap HV

• Electron beam ramping

•Table Driven Beamline Optics for Ion injection from Multiple sources and EBIS ion beam extraction

EBIS Voltage and Timing Controller

Multiple Ion Species (PPM)

• The EBIS highly charged ion beam species and charge state can be selected on a pulse to pulse basis

• Voltage Controller is hardware configured for 3 independent cycles with a repetition factor of up to 15 each

• Software presently allows for use 16 independent beamline optics tables for selecting injection from various external sources or EBIS beam propagation to various diagnostic devices (RFQ, TOF, emittance analysis, etc).

Mamyrin TOF (electrical schematic)

High resolution spectra can be made due to the energy focusing property attained by reflecting the beam to the detector.

Mamyrin TOF (mechanical schematic)

View of the mirror section of the Mamyrin TOF

Emittance (pepperpot)

Ion beam passes through small holes on mask and forms image on downstream phosphor screen

Fast ccd camera allows single shot emittances

Current Transformers

Non-destructive current measurement used for monitoring beams in ion injection arm, at the entrance/exit of EBIS and at the entrance to the RFQ.

The transformer at the EBIS entrance measures both injected current ~10-100A and extracted EBIS current ~100A-10mA

The transformers will be fabricated at BNL and are similar to devices already installed in the Tandem to Booster Beamline and at the Test EBIS

Retractable Faraday Cups will also be used for ion beam measurement during tuning of the ion injection line and for the Inline TOF detector in front of the RFQ. Transformers will serve as monitors during beam delivery.

Profile Monitors

A retractable 32x32 multiwire will be used between the EBIS and RFQ to monitor the beam shape. This technique has been used throughout the CAD facility, including EBIS

Inline Time-of-Flight

• Full ion beam sampled and collected on Faraday Cup

• Ie= 7A; • 10 ms confinement• Au = 83%; C&O = 15%; H = 2%

Summary

The RHIC EBIS will operate on a pulsed High voltage platform which remains at laboratory ground except for the ~1ms necessary for formation of the extracted EBIS beam.

Ion sources are available (and some have already been tested on Test EBIS) which can meet the RHIC EBIS requirements

A compact beamline has been considered, which uses electrostatic switchyards for ion transport in and out of the EBIS. (Based on our experience with TEST EBIS)

Diagnostics will be installed to help tune and monitor the injection and extraction process. The Mamyrin TOF, Inline TOF, Faraday Cups, Current transformers and Profile Monitors have been tested on Test EBIS. A new pepperpot emittance head similar to one used at GSI has been designed and parts are being procured.

E. Beebe LEBT & Ion Injection EBIS Project Technical Review 1/27/2005 LEBT and External Ion...

Documents

Transcript of E. Beebe LEBT & Ion Injection EBIS Project Technical Review 1/27/2005 LEBT and External Ion...