M. Toms

We present measurements of the reduction of light output by plastic scintillators irradiated in the CMS detector during the 8 TeV run of the Large Hadron Collider and show that they indicate a strong dose rate effect. The damage for a given dose is larger for lower dose rate exposures. The results agree with previous measurements of dose rate effects, but are stronger due to the very low dose rates probed. We show that the scaling with dose rate is consistent with that expected from diffusion effects.

Abstract The two Zero Degree Calorimeters (ZDCs) of the CMS experiment are located at ± 140 m from the collision point and detect neutral particles in the |η| > 8.3 pseudorapidity region. This paper presents a study on the performance of the ZDC in the 2016 pPb run. The response of the detectors to ultrarelativistic neutrons is studied using in-depth Monte Carlo simulations. A method of signal extraction based on template fits is presented, along with a dedicated calibration procedure. A deconvolution technique for the correction of overlapping collision events is discussed.

We study the light output, light collection efficiency and signal timing of a variety of organic scintillators that are being considered for the upgrade of the hadronic calorimeter of the CMS detector. The experimental data are collected at the H2 test-beam area at CERN, using a 150 GeV muon beam. In particular, we investigate the usage of over-doped and green-emitting plastic scintillators, two solutions that have not been extensively considered. We present a study of the energy distribution in plastic-scintillator tiles, the hit efficiency as a function of the hit position, and a study of the signal timing for blue and green scintillators.

The Phase I upgrade of the CMS Hadron Endcap Calorimeters consists of new photodetectors (Silicon Photomultipliers in place of Hybrid Photo-Diodes) and front-end electronics. The upgrade will eliminate the noise and the calibration drift of the Hybrid Photo-Diodes and enable the mitigation of the radiation damage of the scintillators and the wavelength shifting fibers with a larger spectral acceptance of the Silicon Photomultipliers. The upgrade also includes increased longitudinal segmentation of the calorimeter readout, which allows pile-up mitigation and recalibration due to depth-dependent radiation damage. As a realistic operational test, the responses of the Hadron Endcap Calorimeter wedges were calibrated with a 60Co radioactive source with upgrade electronics. The test successfully established the procedure for future source calibrations of the Hadron Endcap Calorimeters. Here we describe the instrumentation details and the operational experiences related to the sourcing test.

paper entitled Hops-Yesterday, To-day and To-morrow; the three periods involved were 1870 to 1946, 1946 to the present day, and the future.Mr. Brown first discussed culti vation and the changes in method that had occurred.The influence of Verticillium wilt and machine picking on the varieties grown was dealt with in some detail.Changes in methods of propagation and improved ferti lizers and insecticides were mentioned.New types of dryer and packing were discussed.Mr. Brown concluded by examining future market prospects, bearing in mind that world hop rates were dropping and that present utilization of humulones was inefficient.Present methods were criticized, particularly the lack of incentive to grow good hops.The discussion brought forward comment on the new form of packing into ballots.The cost of the press was given and it was stressed that very minor breakage to the hops occurred.In reply to a question concerning the drying of machine-picked hops, Mr. Brown stressed that a different technique was required as compared with hand-picked samples.Owing to less air circulation, the process is more diffi cult and requires a good deal of experience.Another speaker entered a plea on behalf of the Hops Marketing Board as to guidance from brewers for their requirements, par ticularly of new varieties.New varieties were severely criticized on the grounds of flavour and, in reply to a proposal for better selection of established varieties, Mr. Brown pointed [J.Inst.Brew.out that the Fuggle cannot resist wilt and does not lend itself to machine picking.The cost of production is the chief obstacle to growing hops in areas other than those already well established.

The ever-increasing detector complexity at CERN triggers a call for an increasing level of automation. Since the quality of collected physics data hinges on the quality of the detector components at the time of data-taking, the rapid identification and resolution of detector system anomalies will result in a better amount of high-quality particle data. Therefore, this study proposes CGVAE, a data-driven unsupervised anomaly detection using a deep learning model, for detector system monitoring from multivariate time series sensor data. The CGVAE model is composed of a variational autoencoder with convolutional and gated recurrent unit networks for fast localized feature extraction, long temporal characteristics capturing, and descriptive representation learning. Furthermore, to mitigate signal reconstruction overfitting on anomalous patterns, the CGVAE employs encoded latent feature- and reconstruction-based metrics for anomaly detection. Moreover, the model integrates feature attribution algorithms to explain the contribution of the input sensors to the detected anomalies. The experimental evaluation on large sensor data sets of the Hadron Calorimeter of the CMS experiment demonstrates the efficacy of the proposed model in capturing temporal anomalies.