The Linac 4 H 0H monitor Jean TassanViol

The Linac 4 H 0/H- monitor Jean Tassan-Viol - BI Day 2017 Thanks to : Federico Roncarolo (BE-BI), Gerrit Jan Focker (BE-BI), Araceli Navarro Fernandez (BE-BI), J. B. Ruiz (BE-BI), Morad Hamani (BE-BI), Sylvain Leblanc (BE-BI), Claude Rinaldi (BE-BI), Wim Weterings (TE-ABT) , Louise Jorat (TE-ABT), Bettina Mikulec (BE-OP), Marco Garlasche (EN-MME), Jean-Pierre Corso (EN-ACE), Damien Grenier(EN-STI), Nicolas Thaus (TE-VSC)

Outline • Introduction to new PSB injection region • H 0/H- beam current monitors • Assembly challenges • Electronics • Measurements examples at HST • Conclusions 29/6/2017 Jean Tassan-Viol 3

Linac 4 Half sector test 29/6/2017 Jean Tassan-Viol 4

Introduction to new PSB injection region Stripping foil (x% efficiency) HBSW 1 BSW 2 BSW 3 BSW 4 P+ P+ Circulating beam H 0 Dump H- 160 Me. V H- beam from LINAC 4 29/6/2017 H(=1 proton+2 electrons) To electronics Need to measure H 0 and H- charges ! • On line monitoring of SF degradation • Protect dump in case of foil breakage Jean Tassan-Viol 5

Stripping foil loader and BTV The BTV with its rad hard camera allows operator to check visually the beam and the stripping foil Bea m a Camer Stripping foil loader 29/6/2017 Jean Tassan-Viol 6

Internal view of the BSW 4 tank Beam H 0/H- beam current monitor plates Electrical feedthrough Shielded Connector Ti dump 29/6/2017 The Ti dump is designed to withstand 5 LINAC 4 pulses The monitor plates give a signal proportional to the amount of lost particles An interlock is generated when too many particles are lost Jean Tassan-Viol 7

Monitor principle The ions are stripped when crossing the Ti plates, H 0 leaves 1 electron, H- leaves 2 electrons The output signal is generated by these electrons H 0 or H- P+ Signal readout 29/6/2017 Jean Tassan-Viol 8

Assembly challenges TE-VSC request : no kapton single core copper wire in ceramic beads… Wiring time multiplied by 20 Several issues with too tight clearance gaps of delicate Macor parts Some parts needed to be adjusted in bldg 865 workshop … (thanks to Sylvain) Monitor and dump 29/6/2017 Shielded connector Jean Tassan-Viol Mounting in the vacuum chamber 9

Assembly challenges Dump mounting issue : Shielded connector unconnectable due to dump misalignment Bad thermal contact dump/cooling support Dumps modified to inprove thermal exchange and position Water cooling Modification made by EN-STI 29/6/2017 Jean Tassan-Viol 10

Electronics 1 EDA-03210 VME board for each ring. Two main functions Gives an interlock signal if the foil is perforated or broken : Relatively high current, slow integration. Measures the amount of unstripped Ions (stripping foil efficiency) : Low currents, high speed integration. This information helps deciding whether or not the stripping foil needs to be changed. Expected: 2% of LINAC 4 beam current, change foil at 10% 29/6/2017 Jean Tassan-Viol 11

Electronics : interlock function 1 ring interlock amplifier Low gain. Made to detect big holes in the stripping foil HPlate 1 2, 5* HPlate 2 2, 5* H 0 Plate 1 H 0 Plate 2 EDA-03210 board EDA-03451 Interlock interface + 5* Ref + CIBU-BIS S R Q 5* Software control 29/6/2017 Jean Tassan-Viol 12

Electronics : Single turn amplifier function o o o Injection time can vary from 50 ns up to 150µs Current from each plate is integrated at each ~1µs Booster turn , stored in memory, then sent to FESA Measurement window from 150 to 950 ns For longer injection times the average current can be calculated by software Each input channel has two integrators that work alternately (2 and 3) Dedicated integrator for single short pulse (1) with higher sensitivity On EDA-03210 board 29/6/2017 Jean Tassan-Viol 13

Half Sector Test H- H- beam The half sector test in the Linac 4 transfer line 29/6/2017 Jean Tassan-Viol 14

Measurements at the HST – Calibration Factors Signal on one plate Several set of measurements consisting in: • Reduce H- peak beam intensity and pulse length • Take OUT stripping foil • Steer the H- beam on a single plate at a time (pos. 1, 3, 5, 7 on the sketch) • Each time, normalize the plate signal to the upstream BCT Calibration factor #of charges per ADC unit 29/6/2017 Jean Tassan-Viol 15

Measurement example at HST Relative variation of the calibration factors for different plates and intensities 29/6/2017 Jean Tassan-Viol 16

Measurement example at HST 29/6/2017 Jean Tassan-Viol 17

Measurement example at HST • Qualitative validation of the electronics interlock channel • Using BI-SW FESA server + DB logging service 29/6/2017 Jean Tassan-Viol 18

Conclusions and outlook • Successful validation of the first H 0 -H- monitor prototype (mechanics, electronics + first BI-SW FESA server ) • The prototype of the electronic board is expected for September, and hopefully it’s the final version • The four H 0/H- monitors are assembled , insertion in the vacuum tanks ongoing • 3 spare monitors are ready, they need special containers for long term storage 29/6/2017 Jean Tassan-Viol 19

Thank you 29/6/2017 Jean Tassan-Viol 20