Bunch Shape Monitor Fermilab Linac Md Haider Ali
Bunch Shape Monitor: Fermilab Linac Md Haider Ali Shaim, Kiyomi Seiya US-Japan Collaboration Meeting – 2019 March 21, 2019
Outline v BLD, BLM, or BSM? v Why BLD? v Basic operation v Resolution v RF deflector v Control v BLD results Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
Bunch Length Monitor (BLM), Bunch Length Detector (BLD)? v Developed in late 80’s at INR in Russia by A. V. Feschenko. v Designed and used for longitudinal beam profile measurement in Fermilab Linac ~30 years ago!! v 3 BLD for energy range 116 Me. V to 410 Me. V. v One is taken from the tunnel for HINS usage bunching frequency of 325 MHz (2. 5 Me. V)! v RF deflector has tuning range of 600 to 820 MHz, covers 650 = 325 x 2 MHz. Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
Where it is installed? Two main section of the Linac Drift tube linac (LEL) Bunching frequency of 201. 25 MHz, 116 Me. V HSide-coupled cavity linac (HEL) Bunching frequency 805 MHz, 400 Me. V HThe BLD is installed in the transition area (between the two main section), and where the bunching frequency is 805 MHz. The separation is 4 -m long. Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
Basic operation of the BLD Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
Why BLD? 1. High bandwidth requirement 2. Non-relativistic proton WM Tam, Thesis: Characterization of the proton ion source beam for the high intensity neutrino source at fermilab Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
Resolution of the BLD o Time for secondary e- ejection o Emittance of the secondary eo Path length difference among eo Strength of the RF deflector Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
RF Deflector o 1 – Resonant cavity forming arms o 2 – RF power coupling loops o 3 – RF feedback loop o 4 – Endcaps (tuning) o 5 – Plate size tuning o 6 – Slug tuners o 7 – 0 RF – DC voltage applied here o 8 – 1 MΩ resistor o 9 – Focusing area o 10 – Nylon support Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
RF Deflector (continue) o Deflector is a coaxial like, half wavelength resonator. o Copper arms floated by nylon rings serves as inner conductor. o Adjustable spacing between two ends of the deflector, freq tune by capacitive load. o DC voltage beam steer & focus. CST MWS model for BLD RF deflector Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
Controlling the BLD A simple block diagram for the Linac BLD control system ACNET Gate Manual ACNET (HV) RF Shifter Gate and attenuation Cavity RF HV Plate DC HV Wire HV and current Manual (current) 10 W, 805 MHz Wire motion Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019 Bunch length detector e- Trigger ACNET Preamp Sample and hold ACNET
Controlling the BLD, DAQ: ACNET, ACL ACNET and ACL for setting and reading back BLD parameters. ACL scripting language is developed for DAQ o Set RF phase limit o Set starting RF phase o Step RF phase o Wait for Linac pulse o Readback phase value and EMT signal o Step RF phase Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
Calibration of the focusing plates Tungsten wire emit electrons by applying current to the wire. Calibration can be done without beam running Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
BLD measurement ~25 years ago !! Elliott Mc. Crory et al, Longitudinal Emittance from the Fermilab 400 Me. V Linac Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
BLD supporting equipment's ! HV supply RF supply BLD filament supply DC step. motor contrl Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019 BLD 3 - HV supply DC step. motor contrl BLD 4 - HV supply DC step. motor
Conclusion !! Md Haider Shaim, Kiyomi Seiya, US-Japan Collaboration Meeting – 2019
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