The specifications of pulse magnet power supplies required for Indus-2 are listed in the following table:

In contrast to those for Indus-1, in all the pulsed magnet power supplies for Indus-2, output current waveform is half sinusoidal.

• Indus-2  Septum Magnet Power Supplies
• Indus-2 Kicker Power Supplies
• Solid State Thyratron Trigger Unit
• Delay Drift Correction System

Indus-2  Septum Magnet Power Supplies                                                                                                    [ Go to Top ]

The Indus-2 septum magnets (thin and thick) require half sine wave current pulse. These pulses are generated by discharging a bank of energy storage capacitors into the inductive load of septum magnet via a thyristor switch to form an under damped LCR circuit. The injection of bunches takes place at the peak (flat top) of the half sine wave. A bank of energy storage capacitors has been realized such that the series inductance of the circuit remains low. Eight RG-8/U cables form flexible connection link between power supply and magnet. The whole arrangement was made coaxial to reduce stray inductance.

Power supply for Indus-2 thin septum		Power supply for Indus-2 thick septum

Indus-2 Kicker Power Supplies                                                                                                    [ Go to Top ]

In Indus-2 injection will be carried out by using horizontal multi-turn injection scheme. In this scheme a compensated orbit bump is produced and an electron beam is injected parallel to the bumped orbit via septum magnet. Injection will be carried out in the first long straight section, LS-1. The compensated bump will be produced by using four kicker magnets. A half sine wave type of current pulse has been fixed for Indus-2 kicker power supplies. Injection will take place around peak value of sinusoidal current. Base width of half sine current has been decided to be 3 ms. Current peak required to give requisite deflection has been fixed to be 11 kA.

The required features for the kicker magnet power supplies are: 1) All the four kicker current pulses should have identical waveforms, 2) Kicker current pulse should have requisite degree of pulse to pulse current stability around peak, 3) Kicker current should reduce to a very low value in 1.5 msec. to 1.6 msec from peak so as to reduce the compensated bump to zero, 4) Kicker current pulse should not go negative as it will disturb the stored beam.

All the four kickers have identical mechanical arrangements for pulse generating elements. The peak of the current pulse is stabilized by keeping final stage capacitor voltage constant at a required value. Discharge switch, operating at 1Hz, has to pass a peak current of 11kA at a maximum di/dt of approximately 18kA/µsec which is reduced then by employing a magnetic assist. Time jitter requirement of the pulse is ±20 nsec. 

Solid State Thyratron Trigger Unit:                                                                                                     [ Go to Top ]

Thyratrons are being used in the pulsers for booster extraction kicker, Indus-1 injection kicker and Indus-2 injection kickers. The trigger units used earlier with driver thyratron FX-227 had a jitter in the pulsers of the order of ±10 nsec, which caused poor injection efficiency of the Indus-1 and Indus-2 rings. Solid state trigger units for thyratrons have been designed, fabricated and tested. These units deliver a 1.2kV, 1µs pulse with rise time and jitter of 70 ns and ±1ns respectively at repetition rate of 1Hz. With these units installed in the pulsers for booster extraction kicker and Indus-2 injection kickers, the jitter in the currents of these power supplies has come down to ±3 nsec.

Delay Drift Correction System:                                                                                                              [ Go to Top ]

The delay in current pulse after trigger is applied to a thyratron or an SCR switch drifts due to change in ambient temperature. This drift affects injection efficiency in Indus-2 ring. Delay drift correction unit for the Indus-2 kicker power supplies has been designed and developed. This unit corrects for the delay drift to within a few nsec. Total correction range is ± 128 nsec with a resolution of 1nsec.