1. Spectrap Electronics Evaluation of Cryogenic Components Begin 2009 Stefan Stahl measurements by Stefan Stahl & Zoran Angelkovic

2. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Preface: main objectives challenge : important to have low final temperature=> new amplifier design Resistive Cooling of captured ions to T = 4.2K and ion detection Resistive Cooling of captured ions to T = 4.2K and ion detection Rotating Wall Compression Rotating Wall Compression FT-ICR Detection (optional) FT-ICR Detection (optional) challenge : FT-ICR and rotating wall compression at the same time  m · D² q² · R

3. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Novel Amplifier Design FET with low input capacitance => low heating of LC circuit Additional cascode circuitry further lowers C IN Main former problem (GaAs-FETs) : 1/f-noise and input capacitance lead to increased axial ion temperature of 30 – 70 K (see: g-factor experiments, Gabrielse-setups)

4. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Noise Chart of designed amplifier LC circuit at trap will show about 22nV/(Hz) 1/2 @ 2MHz C in determined to 1.8pF  strong decoupling 6:1 possible Presumably low T noise ~ 6K Using NEC 3508 „super low noise“ HJ-FET (GaAs)

5. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Rotating Wall Compression T = 300K T = 4.2K non-linear filters reduce noise and allow FT-ICR at the same time Low pass functionality, overruled at high amplitudes Established 2008

6. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Frequency and Amplitude response Observations: General functionality verified Clear Voltage Threshold as expected Output Excitation amplitudes somewhat too low Failure of diodes at U in ~ 12V pk or 240mA pk => modifications will be tested coming weeks

7. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Geometrical Arrangement

8. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Another Idea: Charge Detector for Adjustment Sensitive cryogenic charge amplifier on back side

9. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Summary and Outlook Low input capacitance amplifier design verified and tested => suitable for axial detection and resistive cooling Filter unit successfully tested; some weak point discovered, to be solved soon Several components (capacitors, resistors, diodes and FETs) verified for compatibility with 4.2K environment Refine overall circuitry design and adapt to latest geometrical changes Eventually add functionality of cryogenic destructive charge detector Test of completed cryo setup after connecting the trap and room temperature electronics Software control of devices

10. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Thanks a lot for your attention. Email: s.stahl@stahl-electronics.com www.stahl-electronics.com

11. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Spare Slides:

12. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Examples of Coil-Design

13. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Pickup-Elektrode x y Detection of Image Charges, FT-ICR

14. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Pickup-Elektrode ion current signal I t Detection of Image Charges, FT-ICR x y

15. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Pickup-Elektrode ion current signal I Detection of Image Charges, FT-ICR x y very small signal ~fA Signal strength D ~ distance of pickup electrodes

16. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Pickup-Elektrode ion current signal q/m spectrum I I t f x y very small signal ~fA Detection of Image Charges, FT-ICR „FT-ICR“ Fourier-Transform Ion Cyclotron Resonance

17. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Detection of Image Charges, FT-ICR Method is non-destructive Many ion species can be detected at the same time Small sensitivity to space charges compared to TOF Small sensitivity to space charges compared to TOF Useful over a very wide range of ion numbers Useful over a very wide range of ion numbers

18. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components FT-ICR Circuitry

19. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components First H 2 O + Resonance:

20. Spectrap Collaboration Meeting, April 2, 2009 Spectrap Evaluation of Cryogenic Components Shot Noise by Ions and Electrons Creating shot noise while flying through 10 10 electrons/sec. ~ 6 fA/ (Hz) 1/2 10 12 ions/sec. ~ 700 fA/ (Hz) 1/2 