The ABP/HSC sectionneeds a 4 port Network Analyzer

for beam impedance measurements

O.Berrig and J.Kuczerowski Thanks to F.Caspers and C.Vollinger

As we all know, a good tool is half the job

HSC = Hadron Synchrotron Collective effects

Beam Impedance measurements are high precision

Network Analyzer

DUT = Device Under Test

The Network Analyzer sends out a sine wave

A linear device i.e. a device without active electronics, always converts an input sine wave to an output sine wave - but with different amplitude and different phase.It is exactly the amplitude and phase change that we want to know !

The Network Analyzer has an extremely narrow band comb filter, which is centered on the same frequency as the one that is sent out

Wire scanner measurementsneeds 4 port Network Analyzer

In general, a differential measurement needs 2 ports. Differential measurements are normally needed for three reasons:1) Engineering constraints (as we have it

in wire scanners)2) Noisy environments3) Long cables

Transverse Beam Impedance measurements can be done easier

with 4 port Network Analyzer

Using 4 ports avoids the non-linearities in the hybrids and makes the measurement less prone to human errors

Automatic measurements requires automatic calibration unit

After an initial measurement of the approximate position of the resonance frequencies; a narrow calibration can be done automatically around each frequency. Each calibration will contain 1601 points (for 1601 frequencies around each resonance frequency).

NB! There are some disagreements if we really need narrow calibrations to find the Q-factors for the resonances. Maybe swept frequency measurements could be used instead?

E5071 Network Analyzers in CERN E5071C VALUCH 864-R-C15 17-11-2011 160072 E5071C VALUCH 864-R-C15 01-03-2011 160003

2838483 E5071C, 9kHz-4.5GHz. 2-port VALUCH 864-R-C15 27.08.2008

4736785 E5071C. 4-port VALUCH 864/R-C15 05.09.20114483087 E5071C. 4-port TRANQUILLE AD 15.10.2010 159950

4130906 E5071C. 2-port TIMEO 17/R-015 25.06.2009 136775

E5071C SCHWERG 252-1-018 09-01-2012 1618514788986 E5071C, 8.5GHz 4-port SCHWERG 252-1-018 04.11.2011

2520524 E5071C. 2-port CHANEL 9-1-021 16-08-2007 125907

4332129 E5071C. 4-port CASPERS 19/S-003 21-04-2010

To be investigated: What about the electronic pool, could we borrow from them?

E5071C M.Wendt BE-BI-QP 866/1-A26

Requirements

Vector Network Analyzer:4 ports.Frequency range: kHz to 3-4 GHzWith Timing optionAutomatic calibration kit needed

Possible vendors:

Keysight – successor of Agilent (selling through retailers – not directly from Keysight)

Rohde & Schwarz

Anritsu

Pro and Cons for purchasing a 4 port network analyzer

Pro:• Time gained because we do not have to

look for someone to lend us a 4 port network analyzer (This only happens for special measurements e.g wire scanner). Also removes the de-motivational effect of having to “beg & borrow”

• Possibility of measuring several ports simultaneously (e.g. measure horizontal and vertical ports simultaneously on a wire scanner)

• With an extra network analyzer, we can do measurements in the lab, while the other network analyzer does automatic measurements in other parts of CERN

• Transverse measurements becomes easier and less error prone.

• Software only need to be written for one network analyzer type. Saves manpower.

Cons:• Price. Approximately 50 kCHF for

network analyzer and automatic calibration kit.

• We have already bought one hybrid (2000+ CHF). This will now only be used rarely e.g. when several differential measurements needs to be done simultaneously. We could sell the Hybrid to the BI group (TID) and borrow it in the rare cases we need it.