Glass noise

To verify the modelling of the data eolleetion process, calculations of SAT 4, in the entrance window of the XRII was compared to measurements of RNR p oj in stored data as function of tube potential. The images object was a steel cylinder 5-mm) with a glass rod 1-mm) as defect. X-ray spectra were filtered with 0.6-mm copper. Tube current and exposure time were varied so that the signal beside the object. So, was kept constant for all tube potentials. Figure 8 shows measured and simulated SNR oproj, where both point out 100 kV as the tube potential that gives a maximum. Due to overestimation of the noise in calculations the maximum in the simulated values are normalised to the maximum in the measured values. Once the model was verified it was used to calculate optimal choice of filter materials and tube potentials, see figure 9. 

J. M. Clinch, Study of Reduction of Glare, Reflection Heat and Noise Transfer in Air Traffic Control Tower Cab Glass, FAA-RD-72-65, AD747069, NTIS, Springfield, Va., 1972. 

Avoid nuisance noise Provide adequate ventilation Avoid high uniform temperatures Avoid lack of air movement Provide adequate humidity Avoid uniform dull lighting and decor Provide natural lighting avoid tinted glass Ensure staff are motivated... 

Loud noise (143 dB), sonic boom glass failure... 

---