Beam Instrumentation System of CSNS Jilei Sun On

Beam Instrumentation System of CSNS Jilei Sun On behalf of BI group, CSNS, Institute of High Energy Physics 3 RD IPM WORKSHOP, J-PARC, TOKAI 2018 -09 -19

Outline n Overview of CSNS project n Introduction of BI system • • • Beam Current Monitor, BCM Beam Position Monitor, BPM Beam Loss Monitor, BLM Beam Profile Monitor, Wire Scanner Others n Status of the IPM development at CSNS 2

Overview of CSNS project LINAC service building RCS service building Target hall CSNS 3

Layout of CSNS 50 ke. V H- Ion source 3 Me. V RFQ Target station and instruments Peak beam power: 100 k. W 80 Me. V DTL Back-N 1. 6 Ge. V 25 Hz RCS 4

Neutron instruments • • 20 beam lines Finished: SANS; MR; GPPD Founded: 7 beam lines Proposed: other 10 beam ports Engineering PND High resolution PND Target Cooling System neutron irradiation and SEE Long wavelength PND Backscattering spectrometer Neutron physics High energy DG spectrometer Spin echo spectrometer e. V Spectrometer/image Chemical RG spectrometer Nano/Disorder materials PND High pressure PND Cold neutron image Single crystal diffractometer Liquid reflectometer General purpose PND Low Energy RG spectrometer Multipurpose reflectometer High Resolution DG spectrometer Proton beam Small angle diffractometer (PND: Powder Neutron Diffractometer; RG/DG: Reversal/Direct Geometry) Moderator： D+P, LH 2 (20 K） C, LH 2 (20 K) D, Water (300 K) 5

Key milestones • Sep. 2011 Ground breaking • Jun. 2015 RFQ commissioning • Jan. 2016 DTL-1 commissioning • Apr. 2017 LINAC commissioning（60 Me. V） • May 2017 RCS commissioning • Aug. 2017 First Neutron Beam • Nov. 2017 Accelerator, target and beam line joint commissioning, beam power up to 10 k. W • Jan. 2018 80 Me. V injection commissioning 6

Beam commissioning in 2018 80 Me. V injection beam commissioning (18 days) 2018. 01. 04 ~ 01. 13 Linac 2018. 01. 14 ~ 01. 17 RCS/DC 2018. 01. 18 ~ 01. 21 RCS/AC 2018. 01. 22 ~ Test operation + beam commissioning 1660+ hrs beam on target First user’s sample Demo 10 k. W The first user’s paper published in Apr. 9 7

Beam instrumentation system 8

Beam instrumentation system n. System setup strategy CSS OPI NI – PXIe cards Lab. VIEW EPICS release Front end electronics Monitors 9

Beam instrumentation system n 10

Beam Current Monitor @LINAC n Beam Current = [Sum(Valid) – Sum(Background)] / n Valid count Background count n Inaccurate beam current calculated if the beam is unstable • Increase the sampling rate • Use the integrated area of the waveform to calculate the beam current 11

RCS – DCCT n. Commercial product from Bergoz 20 ms Normalized with the RF frequency 12

RCS – SCT Design n Self developed sensor + NI PXIe ADC + Lab. VIEW n Run as the backup of DCCT Measurement range Droop Response time ± 0. 15 A/± 1. 5 A/ ± 15 A Test results ± 0. 15 A/± 15 A <0. 2%/20 ms <50μs 23. 22μs @0. 15 A 9. 23μs @1. 5 A 24. 24μs @15 A 13

RTBT- CT n 3 CTs along the RTBT line n 2 bunches per extraction, 100 ns each n Beam charge measurement for particle number calculation 14

Beam Position Monitor, BPM n LINAC Strip line Libera EPICS Released Bergoz LRB To rbit NI ADC cor Lab. VIEW rec t ion 15

Beam Position Monitor, BPM n RCS & RTBT RCS • Self-developed electronics • TBT or COD mode RTBT • Commercial electronics: Libera Spark • Po. E 16

Beam Position Monitor, BPM n CSNS-RCS orbit correction • Before correction: X, ± 15 mm; Y, ± 7 mm • After correction: X, ± 6 mm; Y, ± 2 mm 17

Beam Loss Monitor, BLM n Ar+N 2, BF 3, Plastic scintillator + PMT n LINAC • X-ray from the DTL tank detected • Beam loss @ 20 Me. V detected DTL 1 BLM 02 DTL 1 BLM 03 MEBTCT 02 18

LINAC - BLM n Low energy beam loss causing fast neutrons n Fast neutrons can be moderated to thermal neutrons by polyethylene, and be detected by BF 3 n 7. 5 cm thick PE added in BLM located under DTL 1 (beam energy 3 Me. V to 20 Me. V) Thermal neutrons 19

RCS - BLM n 75 ionization chamber n 10 Plastic scintillator + photomultiplier 20 ms 7 ms 20

Beam Profile Monitor, Wire Scanner n LINAC • 4 at MEBT line, Carbon Φ 30 μm • 8 along the LRBT line, Tungsten Φ 50 μm • Positive bias (0 ~ 40 V) n Injection • 4 multi-wire scanner n RTBT • 8 along the RTBT line, Tungsten Φ 50 μm 21

Cross check between Wire scanner and BLM n LRWS 01 & LRBLM 01 (located 330 mm down stream of LRWS 01) n Beam current: 12 m. A n Measured beam profile σ: 4 mm n Wire diameter: 50 μm • BLM can be used as the read out of the wire scanner • ~ 1μA current intercepted at ± 3σ position • Thermal electrons may emitted 2000 0 -2000 0 50 100 150 200 250 300 350 -4000 -6000 -8000 -10000 -12000 22

Others n LEBT and MEBT: emittance measurement n LINAC: FCT to do the beam energy measurement n Tune measurement at RCS n Wall current monitor on LINAC and RCS n 23

Status of the IPM development at CSNS 24

Status of the IPM development at CSNS n Response of the residual gas ionization, by FLUKA • Proton energy • Vacuum level n Current status of CSNS-RCS • Proton: 1. 5 e 12 ppp @1. 6 Ge. V • Vacuum: 1 e-6 Pa • Bunch length: ~ 100 ns • Longitudinal detecting area: 3~5 cm • Gain of MCP: 1 e 6 ~ 1 e 7 • Signal level: 100 n. A ~ 100 μA 25

Status of the IPM development at CSNS n Poles gap 300 mm Uniform field area 220 mm× 50 mm Field accuracy ＜ 3‰ Intensity 0. 05 T ~ 0. 1 T Magnet longitudinal length < 1000 mm 26

Status of the IPM development at CSNS n Magnet design By error in ± 120 mm horizontal <<3‰ By error in ± 26 mm longitudinal <<3‰ 27

Status of the IPM development at CSNS n Prototype with Channeltron • Funded by NSFC • Step motor drive • Without magnet IPM test chamber at SNS QUOTE: Dirk A. Bartkoski, Craig Deibele, Yarom Polsky, Design of an ionization profile monitor for the SNS accumulator ring, Nuclear Instruments and Methods in Physics Research A 767 (2014) 379– 384 28

Summary n CSNS running @20 k. W stably, opening to users from this month. The goal is have 50 k. W, 50% of the design goal, before next summer shutdown. n All subsystems of beam instrumentation perform well, we will keep improving and upgrading. n There is no non-invasive profile monitor at CSNS, a channeltron based IPM prototype is under study. 29

Thank you for your attention！ 30

Multi-wire Profile monitor at PBW 31