 And therefore, a terminal voltage stabilization system has to be added to it and that is very important aspect to it. Now that terminal stabilization system or voltage stabilization system depends on what are the inputs and what are the output parameters of the whole system and now they are explained here. Let us see what are the things involved and where the error could come in. See for example, we are using as first is voltage generation and that generation is coming because we are charging the capacitance and capacitor we are charging the capacitor and capacitor is formed because of this high voltage terminal and the pressure vessel. So it is represented by C here then there are various currents for example, the charging current which is flowing so I call it I charging here and that is coming in so voltage is developed because of that. But what are the other loads which the charging current has to match and you can see various loads are that there is a corona, there is a column current which is responsible for voltage gradient. Then there is a because you are after charging there will be some leakage in the accelerating cubes and always some current will flow through that so we call it I tube. And then we are accelerating the beam and that also has to be taken in so this has to this I see or I charging has to at least match with this. And then for corona stabilization system we this is a corona stabilization system here and this is basically a triode which I will explain later but here what is happening is between high voltage and this there is a comm sort of thing and there is a continuously there is a constant amount of current is flowing here because of corona formation. So we try to modulate this by the feedback system so that is how it is but this is a sort of constant corona load all the time because of this. So these are some of the loads and which have to be taken into account. Now how the voltage is done how the voltage stabilization is done one is that we use corona probe and other one is using the GVM itself so let us say that either so this is a system which takes care of this procedure so either you can use one of them so this is coming because of feedback and either the input to this corona stabilization system is either from the feedback of the slits which is coming from the energy or it can be from the GVM itself so you can see that so this is one circuit of corona stabilization system or voltage stabilization system which is used in the 6 million volt tandem accelerator at BRC so we call it folded tandem ion accelerator here now but V is equal to Q by C is the basic formula which we all remember and this is also shown that V the voltage will depend on I belt which we are supplying and current which you are drawing through this and the corona stabilization. So corona stabilization basically we modulate this because V current beam is more or less fixed and I belt has to take care belt or the pallet chain has to take care of this so what we do is that we modulate this modulate I corona or the corona systems here and that is used for corona stabilization units the voltage is established because you can see here that suppose you take this Vendingram and in Vendingram this is the charging system here where I belt is used for charging the high voltage terminal and this is the accelerating cube you can see this is the accelerating cube and this is a resistor chain which is established the voltage gradient here and this is the diet this is a corona stabilization system which is basically nothing but the triode and it's shown here you can see this is the corona stabilization triode system how it works let me explain it in any triode system you know that the load or the current flowing from anode to cathode here depends on how much is the voltage on a screen and normally screen is negatively old negative charge negative voltage is applied now so what we do is that we modulate this this screen voltage with respect to anode and cathode from the beam which is falling on the feedback slates here you can see so what happens let's say the if the screen is more negative then of course the current passing let's say the current going from anode to cathode will reduce so if the it becomes more negative it will become less current will pass through this and if it becomes less negative the more current will pass less negative more current will pass and when the more current is passing the voltage will come down will go down and if it is a current is reduced less current then it will go up so this is how it takes place and you can see here how it is happening so this is there is a in accelerated the beam is accelerated and this is analyzed for for the energy now magnetic field is set up on in this magnet this is called analyzing magnet corresponding to a particular energy and that energy depends on the voltage so if there is a variation in the voltage the energy will change so let us suppose that voltage we know is the correct voltage and if there are two possibilities here all and things can happen voltage we increases by delta v that means ideally we have set up at v0 so v which is actual voltage has become v0 plus delta v so once the voltage has increased the energy beam energy will also increase or it will be higher once it is higher then for a fixed magnetic field deflection will be less here and therefore more beam will fall on beam you can see this we call it high energy now the energy has increased so this we call it high energy slip so the more beam will come and since beam is always diverging so some beam is always falling on both of them a and b but here now because of increase in the energy more beam will fall on v so if you convert this current or the charge into voltage and take the difference that means vb minus va then you will see that if it is falling the energy has increased here that means vb minus va will be positive and when you add this positive this becomes less negative and when it becomes less negative means more current will pass through and and when the more current is passing through the voltage will come down now that is what we want is because the voltage has increased wanted to bring it down and that is what is happening so for a fixed magnetic field deflection will be less and hence beam will fall on slit v we call it high energy slip the charge is converted to voltage through some circuit here because if the charge collected on this the voltage difference vb minus a as I explained this is will be positive now this is added to the screen voltage which is this voltage which is that negative potential so when the positive you are added to is it becomes less negative now and as a consequence of that the current will more current will flow more current will flow from n a to cathode that means it is a more load in the triode circuit and the voltage will come down or decrease to v value you can adjust the parameters in such a way that it exactly matches the and the voltage will come down and it will become v0 again and that is that is what we wanted so this is called voltage stabilization so this is one one situation when the voltage has increased now suppose the voltage decreased that means it has become v0 minus delta v what will happen now the voltage has decreased and therefore energy will be lower this energy is lower so energy is lower for a same magnetic field there will be more deflection and therefore more deflection means the more beam will fall on this this slit a which we call it at low energy because they say low energy slit so more beam falls on a so if you take that again the difference that means voltage we can say v v minus v a or we call it v v a v then it will be negative now because it is falling on this we are taking b minus v so it will be negative so when you add this negative to the negative it will be more negative it will be more negative and screen will be more negative means less current will flow through through the circuit that means this circuit and less current will flow less so load is you are decreasing the load and this will amount to voltage will go up now load has reduced so voltage will go up and that is what you want so this is nothing but the voltage stabilization so this is how the voltage stabilization takes place using this is one of the method other method is as I said that this even the generating voltmeter itself can also be used so what you can the same procedure will be same so what is happening there that generating voltmeter as measured let's say voltage v naught and if slightly increases then you again measure it it has become v naught plus delta v or when it decreases to become v naught minus filter so then this can again give a feedback in the generating voltmeter itself and that also can be used in the similar the arguments are same and therefore it can also be used for voltage stabilization so you can see that this circuit here what you are seeing here this circuit is using the voltage stabilization using the feedback from the from the slits and that you call it slit mode you can use full slit mode other one is that you can have the the the correction or the feedback from the generating voltmeter itself so you compare the voltages actual voltage with the reference voltage which is v naught and then give the feedback to this system so this is given here and when you do it it basically modulates the the corona current here in this in this region and that increases or decreasing the load this circuit was designed by mj kansara sapna padankumar and colleagues of ia dd brc it worked very well and we could achieve in both the cases the voltage stabilization of about 2 k e v at highest voltage of 6 million volts so if this circuit worked very well so to summarize the whole thing is that although initially this gb m measurements were used to get an idea about the voltage value particularly to avoid the corona discharges but later on the with the with the advancement in the technologies even with the gbms voltage stabilization is also done nicely as well as the voltage measurements have also been done accurately now in this one one of the contributions in the error will come due to raster values and therefore we have to use high quality resters and if we use that high quality resters and take care of other things the voltage is stability is of 10 power minus 4 less than 10 power minus 4 can be achieved delta v by v of less than 1 minus 10 power minus 4 can be achieved and have been achieved and this this is equivalent to 1 k e v in 10 million volts this is a very good however why is still if you want to go to even better measurements then we have to measure or determine the energy not based on this but based on more accurate more accurate methods which are based on the magnetic field value calibrations using the nuclear reactions and the nuclear reactions of two types have been used for calibration and one is resonance type they are very accurate values they give or other one is the neutron thrush world value these experiments have been used and they give the most accurate values thank you very much