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Jiangmen Underground Neutrino Observatory (JUNO) is constructed to probe multiple physics goals, including determining the neutrino mass ordering (MO), measuring solar neutrinos, detecting supernova neutrinos, etc. A large Liquid Scintillator (LS) detector with a high energy resolution is being built to determine the neutrino MO within 6-year of data taking. To accomplish this goal, a calibration complex has been designed. Concerning the energy leakage near the LS boundary, a Guide Tube Calibration System (GTCS) will be deployed on the outer surface of the JUNO central detector to help better understand the boundary effect. A fitting algorithm has been presented during the design of GTCS considering the overlap of full-energy peak and Compton tail. In this paper, we verify the fitting algorithm experimentally, using a radioactive source in the Daya Bay experiment. The maximum bias of full-energy peak for the experiment at Daya Bay is less than 1.0% even if a change of ±20.0% in acrylic density was assumed. Besides, the tuned acrylic density is applied in JUNO GTCS simulation. The maximum uncertainty estimation of GTCS energy response in total is 0.52%, satisfying the JUNO GTCS requirement which is 1.0%.

A Guide Tube Calibration System (GTCS) has been designed for the Jiangmen Underground Neutrino Observatory (JUNO), in order to measure the detector energy response near the outer radius of the active volume. Recently, a prototype system has been constructed and tested, and the calibration algorithm has also been studied to evaluate the risk when the simulation tuning and the error control fail. In this paper, we first report its construction and the performance tests in the lab. Then the influence on the global energy measurement caused by the simulation bias of GTCS is discussed, in order to make sure the algorithm is qualified.

The Jiangmen Underground Neutrino Observatory (JUNO) is designed to determine the neutrino mass hierarchy using a 20 kton liquid scintillator detector. To calibrate the detector boundary effect, the Guide Tube Calibration System (GTCS) has been designed to deploy a radioactive source along a given longitude on the outer surface of the detector. In this paper, we studied the physics case of this system via simulation, which leads to a mechanical design.