TY - JOUR
T1 - Conducted EMI reduction on the pulse tube cryocooler
AU - Eshraghi, M. J.
AU - Cho, Myongwon
AU - Kim, Jin Mok
AU - Sasada, Ichiro
PY - 2009/6
Y1 - 2009/6
N2 - Pulse tube (PT) cryocoolers can be used to cool SQUIDs, however their electromagnetic interference (EMI) through the conducted high frequency noise currents are normally too large to operate SQUIDs. In this paper, high frequency noise currents of a pulse tube cryocooler system are simultaneously observed at several critical points to analyze conducting paths of the noise currents and to find a solution for this problem. High frequency noise currents are detected by current sensors consisting of a current transformer and a terminating resistor at the secondary side. By covering three-phase power lines and a neutral line connecting the valve motor to the inverter with a copper mesh, and by using it as an additional neutral line, conducted EMI (noise currents) to the cryostat has bee reduced by one fifth. With this treatment, SQUIDs have been operated normally.
AB - Pulse tube (PT) cryocoolers can be used to cool SQUIDs, however their electromagnetic interference (EMI) through the conducted high frequency noise currents are normally too large to operate SQUIDs. In this paper, high frequency noise currents of a pulse tube cryocooler system are simultaneously observed at several critical points to analyze conducting paths of the noise currents and to find a solution for this problem. High frequency noise currents are detected by current sensors consisting of a current transformer and a terminating resistor at the secondary side. By covering three-phase power lines and a neutral line connecting the valve motor to the inverter with a copper mesh, and by using it as an additional neutral line, conducted EMI (noise currents) to the cryostat has bee reduced by one fifth. With this treatment, SQUIDs have been operated normally.
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U2 - 10.1109/TMAG.2009.2020548
DO - 10.1109/TMAG.2009.2020548
M3 - Article
AN - SCOPUS:66549114940
VL - 45
SP - 2754
EP - 2757
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
SN - 0018-9464
IS - 6
M1 - 4957755
ER -