1. ECR ion sources for MedAustron
 Project and ion source description
 Operation, performance, limitations
 R&D (achieved + interests)
L. Penescu
CERN - PSI Ion Source Discussion Meeting
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

2. General description Medical application: Keywords for the ion source:
 extensive safety checks on the beam quality;
 continuous and reliable operation
Keywords for the ion source:
 Stability;
 Reproducibility;
 Reliability;
 Versatility (H3+, C4+,…)
 Accessibility
 Automated control
IS specifications:
H3+ intensity
500 µA
C4+ intensity
200 µA
Emittance
180  mm mrad
Stability
± 2.5%
Reproducibility
< 5%
Contaminants
< 1% (at Q/M=1.3)
Startup time
≤ 2h
No operator intervention
≥ 8h
Beam availability
≥ 98%
X-ray dose “at contact”
≤ 0.5 µSv/h
Pulsed operation
1 to 50 ms
0.5 to 10 Hz
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

3. Implementation Time frame (sources):
 : strategy definition, tendering
 : production phase
 : commissioning and tests
 2015: first patient
Layout:
 4 branches in Wiener Neustadt ( …)
 1 branch at the Injector Test Stand at CERN (2012)
MA Injector, Wiener Neustadt
MA Injector Test Stand, CERN (bld. 184)
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

4. System description Three identical units, contracted with Pantechnik;
Including: - complete pumping,
- steering magnets,
- spectrometer,
- supports,
- shielding.
1 unit
2 units to be delivered Neustadt.
Central body of the ion CERN
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

5. Status outline Running with H beams - long-term behavior of ion source
- commissioning of LEBT elements
Performance tests
- sets of operation parameters for nominal performance
- limitations
- reliability and reproducibility
Optimization and debugging
- X-ray emissions and shielding
- automatic procedures
- comprehensive operational diagnose and prediction
- failure statistics
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

6. Operational data H3+ intensity range: Any value from ~15µA to ~600µA
Stability: Specification of ±2.5%
Best performance: ±0.4%
Emittance: Specification: 180 pi.mm.mrad
(geometrical, nominal intensity)
First values:
H plane: 44.5 pi.mm.mrad (RMS)
V plane: 42.7 pi.mm.mrad (RMS)
Safety measures:
Hydrogen operation (gas: H2)
 gas bottle placement, exhaust pipes
Carbon operation (CO2 + He)
 X-ray shielding, radiation monitoring
Runtime: several hours daily; shut down at night
Beam stabilization times (H3+)
“Morning” startup: ≤15min
After vacuum break: ~1h
4 µA
500 µA
30 s
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

7. Failure statistics High Tension related Access related Control related
Problem
Detail
Measure(s)
(1x) perforation of the DC breaker in the RF waveguide.
 Careful cleaning;
 Thicker insulation sheet used (1mm Teflon, instead of 0.5mm).
(1x) break of a thermometer in the water cooling circuit.
 Added grounding connection.
(1x) break of the communication card of the RF amplifier.
 Added “lightning protection” connector.
(1x) broken cables of the gas isolation valves.
 Using the chiller as access barrier (temporary);
 Adding protective structure (final, ongoing).
High Tension
related
Access related
Control related
The PXI became non-responsive several times; had to be reinstalled.
Several communication problems; debugged.
PP a-LPE_Ion_Sources_Status_MATAC11.pptm
Liviu Penescu
ECR ion sources for MedAustron

8. Performance tests Performance figure: Parameter influence: Parameter
Intensity
Emittance
Stability
Reproducibility
Responsivity (response time, discrimination precision)
Performance figure:
Parameter influence:
Parameter
Unit
Intensity
Emittance
Stability*
Gas flow
mbarl/s X
DC Bias potential V
HT Puller potential kV
HT Focus potential
Extraction gap mm
RF Tuner position
RF Generator frequency
GHz
RF Generator attenuation
dBm
RF Amplifier gain
* The “fine” stability is referred here. The long term stability is affected by the stability of ALL the parameters.
Also, indirectly, ALL change in intensity also affects the emittance.
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

9. Beam composition and profilesH
Beam Spectrum (H operation) V
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

10. Intensity tuning Liviu Penescu
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

11. Stability optimization
Dependent ONLY on the internal source parameters.
Several types of instability identified.
60 µA
DC Bias
RF Tuner
10 µA
Puller
7 µA
30 s
90 µA
RF Tuner
Focus
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

12. Emittance tuning H V First results
Courtesy of E. Sargsyan and F. Osmic H
89% of the beam within 180 pi.mm.mrad emittance in H plane V
86% of the beam within 180 pi.mm.mrad emittance in V plane
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

13. X-ray status  Situation different for the two beam types:
- Hydrogen operation: OK.
- Carbon operation: X-ray radiation too high (up to several mSv/h).
 Additional shielding mandatory for Carbon operation.
 Complicating factor: for the same set of Source operation parameters, the X-ray radiation can have different values, depending on:
Nominal < Conditioning < Unstable
 The strategy is to shield for “nominal” and to fix the upper threshold of X dose by using a “mini-alarm”.
 Very important for the shielding design: - origin of X-rays;
- energy distribution of X-rays.
 Different situations have been investigated:
- with/without beam extraction;
- pulsed operation;
- measurements “behind” different thicknesses of Pb.
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

14. Shielding options A – full box in Lead
(thickness from 0.5cm to 3cm,
depending on position)
B – Redesigned plasma lens (in Tantalum)
plus light structure in Lead (thickness ~0.5cm)
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

15. With the re-designed plasma lens in Tantalum
X-ray values
After installation
With the re-designed plasma lens in Tantalum
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

16. Automated operations
Several milestones defined for the ion source physical state.
The passage to any of the milestone states can be done automatically.
Normal operation
VIP operation
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

17. Real-time Diagnose and Prediction
Global status: “Ok”, “Warn”, “NotOk”
Status of “Physical State” and “State Machine”.
Stability monitoring (1Hz, continuous):
8 “internal” parameters plus “external” FC
- monitoring of the current value vs. “Error” and “Warning” thresholds;
- monitoring of their standard deviation.
Fast Data Acquisition (10kHz, on demand):
6 “internal” parameters.
Data logging. 
Warn
Error
FDAQ
Prediction
Estimation of “destabilization times”, based on the trends of:
- injection pressure;
- extraction pressure;
- FC current.
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron

18. R&D interests (H3+ and C4+)
Minimization of X-ray emission
Full range intensity tuning
Factors generating instabilities
Automated control
Factors generating instabilities
Emittance optimization
Extension of intensity range
Factors limiting the reliability
Automatic regulation
Effects of Carbon deposition on the IS performance (H and C)
Beam extraction modeling
Plasma modeling
- Ion origin in the plasma
- Parameter dependence of CSD (extracted vs. internal)
- Energy transfer and particle losses inside plasma
- Plasma coupling (electrodes, RF circuit)
CERN - PSI Ion Source Discussion Meeting
Liviu Penescu
ECR ion sources for MedAustron