**
Basic BEA papers about FCTs, and special info for FCTs in FAIR HEBT lines:**

[[https://www-bd.gsi.de/dokuwiki/lib/exe/fetch.php?media=instruments:n-fct:fct_electronicschain.pdf|Calculated Charge Resolutions for Fast Current and Resonant Transformers]]

[[https://www-bd.gsi.de/dokuwiki/lib/exe/fetch.php?media=instruments:n-fct:transformer_resolution.pdf|Signal Estimates and Electronics Scheme for Fast Current Transformers in High-Energy Transfer Lines]]

[[https://www-bd.gsi.de/dokuwiki/lib/exe/fetch.php?media=instruments:n-fct:fct_pulseattenuation.pdf|Signal Distortion in Coaxial Transmission Lines: Application to Logic Pulses, Photomultiplier Pulses, and Fast Current Transformer Signals]]

[[https://www-bd.gsi.de/dokuwiki/lib/exe/fetch.php?media=instruments:n-fct:fct-response--htp.pdf|Investigation of a little bit of
Fast Current Transformer response at HTP]]

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**
Already in 1995, four GSI-made FCTs T-DS114 had been installed in the GSI HEST lines:** 

**GTE1DT1FP\\ GTE5DT1FP\\ GHHTDT7FP\\ GHTPDT1FP**

After 2005, commercially available FCTs from [[https://www.bergoz.com/fct?bs=5|Bergoz Instrumentation]] have been added to SIS 18 and ESR: 

**GS01DT1FP**, which had been relocated from it's initial position in GS07, eventually**\\ GE02DT1FP**

----

**Main characteristics of the installed FCTs:**

**GSI FCT in HEST lines**
  * GSI model no.: T-DS114
  * ID of toroid = 160mm
  * sensitivity/transimpedance: 0.23 A/V (or 4.2 V/A)
  * @termination: 50 Ω
  * low freq. cutoff -3dB: ~2 kHz
  * high freq. cutoff -3dB: ~300 MHz

[[https://www-bd.gsi.de/dokuwiki/lib/exe/fetch.php?media=ed:t-ds114.pdf|GSI FCT datasheet]]

**Bergoz FCT in SIS18**
  * Bergoz model no.: FCT-260-50:1-LD-H
  * ID of toroid = 260 mm
  * sensitivity/transimpedance: 0.5 V/A
  * @termination: 50 Ω  
  * low freq. cutoff -3dB: ~200 Hz
  * high freq. cutoff -3dB: ~690 MHz
  * <color #ed1c24>separate output for Ring RF through power divider, which reduces sensitivity by factor 2 !</color>

[[https://www-bd.gsi.de/dokuwiki/lib/exe/fetch.php?media=ed:sis-fct-260-50_report.pdf|documents sensor #1768]]

[[https://www-bd.gsi.de/dokuwiki/lib/exe/fetch.php?media=instruments:n-fct:wepf18.pdf|A FESA DAQ FOR FAST CURRENT TRANSFORMER IN SIS 18]]

{{:instruments:n-fct:fct-toroid.png?nolink&400|}}
**Fig:** 
Typical Bergoz FCT toroid

**Bergoz FCT in ESR**
  * Bergoz model no.: FCT-260-1.25-LD
  * ID of toroid = 260 mm
  * sensitivity: 1.25 V/A
  * @termination: 50 Ω
  * low freq. cutoff -3dB: ~650 Hz
  * high freq. cutoff -3dB: ~570 MHz
  * <color #ed1c24>separate output for Ring RF through power divider, which reduces sensitivity by factor 2 !</color>

[[https://www-bd.gsi.de/dokuwiki/lib/exe/fetch.php?media=ed:esr_fct-documents.pdf|documents sensor #3106]]