No Arabic abstract
In Japan, China and Russia, there are several test beam lines available or will become available in near future. Those are open for users who need electron, muon and charged pion beams with energies of 1-50 GeV for any tests of small-size detectors. In this manuscript I present a current status of those test beam facilities in the Asian region.
A prototype Secondary-electron Emission Monitor (SEM) was installed in the 8 GeV proton transport line for the MiniBooNE experiment at Fermilab. The SEM is a segmented grid made with 5 um Ti foils, intended for use in the 120 GeV NuMI beam at Fermilab. Similar to previous workers, we found that the full collection of the secondary electron signal requires a bias voltage to draw the ejected electrons cleanly off the foils, and this effect is more pronounced at larger beam intensity. The beam centroid and width resolutions of the SEM were measured at beam widths of 3, 7, and 8 mm, and compared to calculations. Extrapolating the data from this beam test, we expect a centroid and width resolutions of 20um and 25 um, respectively, in the NuMI beam which has 1 mm spot size.
The narrow band beam of ENUBET is the first implementation of the monitored neutrino beam technique proposed in 2015. ENUBET has been designed to monitor lepton production in the decay tunnel of neutrino beams and to provide a 1% measurement of the neutrino flux at source. In particular, the three body semi-leptonic decay of kaons monitored by large angle positron production offers a fully controlled $ u_{e}$ source at the GeV scale for a new generation of short baseline experiments. In this contribution the performances of the positron tagger prototypes tested at CERN beamlines in 2016-2018 are presented.
The scintillator-strip electromagnetic calorimeter (ScECAL) is one of the calorimeter technologies which can achieve fine granularity required for the particle flow algorithm. Second prototype of the ScECAL has been built and tested with analog hadron calorimeter (AHCAL) and tail catcher (TCMT) in September 2008 at Fermilab meson test beam facility. Data are taken with 1 to 32 GeV of electron, pion and muon beams to evaluate all the necessary performances of the ScECAL, AHCAL and TCMT system. This manuscript describes overview of the beam test and very preliminary results focusing on the ScECAL part.
The high design luminosity of the SuperKEKB electron-positron collider is expected to result in challenging levels of beam-induced backgrounds in the interaction region. Properly simulating and mitigating these backgrounds is critical to the success of the Belle~II experiment. We report on measurements performed with a suite of dedicated beam background detectors, collectively known as BEAST II, during the so-called Phase 1 commissioning run of SuperKEKB in 2016, which involved operation of both the high energy ring (HER) of 7 GeV electrons as well as the low energy ring (LER) of 4 GeV positrons. We describe the BEAST II detector systems, the simulation of beam backgrounds, and the measurements performed. The measurements include standard ones of dose rates versus accelerator conditions, and more novel investigations, such as bunch-by-bunch measurements of injection backgrounds and measurements sensitive to the energy spectrum and angular distribution of fast neutrons. We observe beam-gas, Touschek, beam-dust, and injection backgrounds. We do not observe significant synchrotron radiation, as expected. Measured LER beam-gas backgrounds and Touschek backgrounds in both rings are slightly elevated, on average three times larger than the levels predicted by simulation. HER beam-gas backgrounds are on on average two orders of magnitude larger than predicted. Systematic uncertainties and channel-to-channel variations are large, so that these excesses constitute only 1-2 sigma level effects. Neutron background rates are higher than predicted and should be studied further. We will measure the remaining beam background processes, due to colliding beams, in the imminent commissioning Phase 2. These backgrounds are expected to be the most critical for Belle II, to the point of necessitating replacement of detector components during the Phase 3 (full-luminosity) operation of SuperKEB.
We developed an electron beam size monitor for extremely small beam sizes. It uses a laser interference fringe for a scattering target with the electron beam. Our target performance is < 2 nm systematic error for 37 nm beam size and < 10% statistical error in a measurement using 90 electron bunches for 25 - 6000 nm beam size. A precise laser interference fringe control system using an active feedback function is incorporated to the monitor to achieve the target performance. We describe an overall design, implementations, and performance estimations of the monitor.