IC64-16 - Pyramid Technical Consultants
Contents
1. Environment Integral Strip cathode Anodes 1 2 HV monitor plane A Axis A X sense readout input and readout readout 1 32 33 64 loopback 9 Gas port 6 ES Sy Environ A pee A1 i A2 Anode 3 HV input and loopback 6 33 64 Strip cathode Axis B Y sense readout 1 32 va Integral plane B 33 readout O gt Environment S monitor E readout ramo 1064 16 64 Channel lon Chamber _ a e 2 Gas port Figure 7 Beam entrance face in the standard orientation showing connection points Note that the sense of X and Y shown here is only illustrative and local X and Y would typically be defined in beamline coordinates the correspondence between readout in IC64 16 1064 16 User Manual IC64 16 UM 141204 Page 20 of 53 PSI System Controls and Diagnostics strip units and absolute beamline coordinates depends on the mounting of the chamber and any offsets discovered during physical surveys When the beam enters through the face shown in figure 7 the sequence of electrodes and air gaps that the beam passes through is as shown in the following figure Sues IGIBU MINAS IL mm Y 09 N Q o O os 68 o 83 v O ES woe Se DD 25 Y ES is Ses 9 E Cc D Oo Cc a 2S C lt lt Nominal beam entrance face with decal Nominal beam exit Internal connection SS eS 13 9 3 0 5 0 5 0 3 0 13 9 Mounting surface 1 Figure 8 Sequence of elect2. Function Connector on the IC64 16 Axis A readout Integral plane A readout Bias voltage input anodes and 2 Bias voltage readback anodes 1 and 2 SHV receptacle Environment sensors redundant Dsub 9 pin male Axis B readout DSub HD 44 pin male Integral plane B readout Lemo OB 4 pin female Bias voltage input anode 3 SHV receptacle IC64 16 User Manual IC64 16 UM 141204 Page 22 of 53 PSI System Controls and Diagnostics Bias voltage readback anode 3 SHV receptacle The bias voltage readback outputs are intended for systems that can provide independent monitoring of the voltage delivered and the voltage returned If this is not available then the readback SHV connectors can be left unconnected Independent readout of redundant dose measurement electrodes is required by IEC 60601 However if independent biasing of the anodes is not required in your application then a single bias input voltage can be connected and the corresponding output can be connected to the other input using a short link cable CAUTION Risk of arcing damage All electrodes within the IC64 16 must be connected to electrometer inputs HV power supplies or ground Any electrode left floating could charge up over time from beam created ionization of the fill gas and internal arcing may result This may damage the electrode surfaces and readout traces Ensure all connections are made Any electrode connectors that are not being read out o
3. The energy to produce an ion electron pair in the gas filling is almost constant for a given target species and very small compared to the energy carried by the ion hence the minimal effect on the beam 34 0 eV 36 4 eV Oxygen gas 32 2 EN 26 3 eV 42 7 eV The amount of ionization per ion in the gas filling of the ionization chamber depends upon the gas composition essentially constant if atmospheric air is used the distance travelled through the gas the pressure of the gas the energy of the ion and its charge state If the factors IC64 16 User Manual IC64 16 UM 141204 Page 30 of 53 PSI System Controls and Diagnostics mentioned above are fixed by control or by calibration for example against a Faraday cup collector then the effective gain of the ionization chamber chamber signal ion beam current is known at the particular energy and the chamber can be used to give a good indication of beam current The approximate gain curve for the IC64 16 with 3 and 5 mm electrode spacings as a function of beam energy for protons in air at standard ambient temperature and pressure is shown in figures 16 and 17 below CAUTION If the 1C64 16 is used for critical dosimetry applications then you must use accurate gain values referenced to traceable standards and regularly validated If the IC is only being used to measure the position and shape of the beam then we don t need to know the gain accurately only that it is c
4. 7 6 m Two or four loopback configuration needed per IC64 16 Other lengths available CAB D9M 25 D9F Cable multiway DSub 9 pin male to DSub 9 way female 25 7 6 m One or two redundant sensor readout configuration needed per IC64 16 6 2 2 Cable sets CAB SET ICCLN 6 6 Cable set 6 6 low noise comprising qty 4 colour coded CAB D44F 6 6LN D44M qty 2 CAB L304M 6 6LN L304M qty 4 CAB SHV 6 6 SHV qty 2 CAB D9M 6 6 D9F qty 2 ADAP ENV D9F D25M One set needed to connect one IC64 16 to two 16400 electrometers CAB SET ICCLN 20 Cable set 20 low noise comprising qty 4 colour coded CAB D44F 20LN D44M qty 2 CAB L304M 20LN L304M qty 4 CAB SHV 20 SHV qty 2 CAB D9M 25 D9F qty 2 ADAP ENV D9F D25M One set needed to connect one IC64 16 to two 16400 electrometers 6 3 Consumables DES_PK_IC64 Pack of three desiccant sachets sufficient for one desiccant replacement cycle 1C64 16 User Manual IC64 16 UM_141204 Page 9 of 53 PSI System Controls and Diagnostics 7 Intended Use and Key Features 7 1 Intended Use The IC64 16 is intended to provide position shape and intensity readout of high energy ion beams nominally proton beams in the energy range 30 to 350 MeV The beams pass through the chamber with minimal scattering and energy loss The IC64 16 will typically form a part of a complete beam dosimetry suite in a particle accelerator system a specific example being the treatment room nozzle in a particle therapy system
5. of the strip width or less for normal beam currents and noise levels A center of mass calculation CoG is simple to calculate and makes no assumptions about the shape of the peak However it is unreliable if the whole peak is not included or if excess background noise or offset is included A fit to a Gaussian 1s often the best solution Pyramid real time controller products include fast algorithms for peak fitting and centroid finding 10 2 1 Beam centroid The sensor strip geometry is controlled to high accuracy by the use of precision electrode machining techniques The center of the pattern is between the 32nd and 33rd strips in each axis Thus in a perfect system with no offsets a perfectly centered beam would give a centroid reading of 32 500 strips in X and in Y which you would typically translate as a physical position of 0 000 0 000 mm If you determine a peak position Px Py expressed in strips then the position in physical units in the nominal C64 16 coordinate system figure 7 is given by Xs Px 32 5 S Ys Py 32 5 S Ionization chambers like the IC64 16 are usually required to return absolute positions in an external coordinate system This may be the beamline coordinate system or the coordinate 1064 16 User Manual IC64 16 UM 141204 Page 34 of 53 PSI System Controls and Diagnostics system of a patient imager in the case of the particle therapy application To translate to the beamline coordinate s
6. where the signal is increased greatly by electron avalanching This regime is generally avoided in high energy ion beamlines because it is less stable and the chamber is more prone to degradation from beam exposure The integral plane electrode collects charge over the whole active area of the IC and delivers it to a single readout channel The strip electrodes partition the measured charge according to where it is formed in the gap The partitioning is linear and direct because the field is uniform in the gap Although the readout strips on the cathodes are separated by very small gaps all the induced signal and charge eventually arriving at the cathodes is routed by the electric field onto 1664 16 User Manual IC64 16 UM 141204 Page 28 of 53 PSI System Controls and Diagnostics the strips Therefore you can safely assume that the effective strip width is the same as the strip pitch and the conversion to physical units is given by multiplying a result in strips by the strip pitch Anode Strip cathode Beam ion Le E al Fy lt t F W Pre amps VVVVVVVV Figure 14 Signal partition on strip cathodes 10 1 2 Pulsed beams For DC or slowly varying ion beams the signal measured on the cathodes will simply track the beam current related by the gain factor of the ionization chamber If your particle accelerator is a type such as a linac or synchrocyclotron that produces a series of shorts pulses then the time response of the i
7. Beam ion Py ee oe y E a ae lt Pre amp Pre amp Figure 18 Increased path length and ionization from an inclined trajectory The chamber gain increases by a factor y 1 tanay tan ay where ax and ay are the angles of the beam in the two transverse axes to the normal to the electrode planes For beam deflection angles used in high energy particle beam deflection systems typically less than 7 degrees the gain correction 1s small less than 1 5 and can often be ignored 10 1 5 Recombination The upper beam current measurement limit of the 1onization chamber is set by recombination of the ions and electrons before they can be collected on the electrodes which reduces the measured current Recombination is a function of the local beam current density the electric field strength the gas composition and pressure Pulsed beam systems present the greatest challenges because the peak beam current in the pulse maybe high Using a higher bias voltage to increase the ion and electron drift velocities is the simplest mitigation A smaller anode cathode gap 1s also a good mitigation but comes at the cost of lower chamber gain and it becomes harder to achieve excellent gain flatness and highly stable operation The standard 3 mm and 5 mm gaps of the IC64 16 are a good compromise and are suited to both DC and pulsed beam measurements At low current densities corresponding to typical ion beam current densities up to arou
8. It is designed to be read out by a pair of the matching 16400 electronics units or one 1128 electronics unit plus an independent readout and bias for the second integral plane electrode However any electronics able to measure very small currents on multiple channels can be used The IC64 16 performs an almost non invasive measurement of the ion beam due to its use of very thin film electrode and window materials The ion beam passes through the device leaving measureable amounts of ionized gas in the electrode gaps but the total energy deposited is tiny compared to the beam energy The amount of scattering the beam receives is very small and can be neglected for most purposes A particle therapy dosimetry system requires two independent integral plane measurements of the dose delivered by the ion beam The IC64 16 provides the necessary independently biased and connected integral plane electrode to permit this The operating environment should be clean and free of vibration and electrical interference Users should be familiar with low current measurement and the general handling of sensitive equipment 7 2 Key Features e Large active area and high position resolution e Very low scattering e Good radiation resistance through use of thin polyimide film electrodes e Dual independent integral plane electrodes e Independent 64 strip electrodes for position readout in both transverse axes e Small integral plane electrode gaps to allow h
9. System Controls and Diagnostics Mounting face 1 Mounting face 2 Figure 5 IC64 16 mounting surfaces The standard arrangement involves fixings to the two mounting surfaces leaving a clearance as necessary for the gas fitting There are M6 tapped holes 5mm dowel holes and fiducials on the IC64 16 housing as shown in figures 1 and 2 A stabilizing attachment can be made to the features at the opposite corner figure 6 Locating hole M6 hole Figure 6 Additional mounting features IC64 16 User Manual IC64 16 UM 141204 Page 19 of 53 PSI System Controls and Diagnostics If the IC is being used in a particle therapy nozzle then the beam exit typically needs to be kept clear so the beam should enter on the connectors face The cables can route naturally back along the beamline Figure 7 shows the beam s view on the entrance face of the IC for this arrangement Assuming that mounting face 1 is at the bottom as shown the right hand connectors read out the vertical sensing axis horizontal electrode strips and increasing strip number corresponds to increasing vertical position The top connectors read out the horizontal sensing axis vertical electrode strips and increasing strip number corresponds to increasing distance to the right The strip numbering assumes readout by 16400 or 1128 electrometers with strip 1 connected to channel and so on
10. mm fill gas 12 5 um polyimide with 0 1 um Al both sides window Water equivalent 195 um including windows electrode layers and atmospheric thickness protons air filling Vibration should be minimized lt 0 1g all axes 1 to 50Hz Ambient sound should be minimized at frequencies below 300 Hz to prevent microphonic pickup Shipping and storage Special transport case included with the product must be used environment 510 40C lt 80 humidity non condensing Vibration lt 1g all axes 0 1 to 100 Hz Dimensions See figures 1 to 4 for dimensions 1664 16 User Manual IC64 16 UM 141204 Page 13 of 53 PSI System Controls and Diagnostics DESICCANT CHAMBER 173 22 0 46 1 Lot d ee ey gt lt 328 0 3313 Figure 1 1C64 16 dimensions mm and mounting face 1 IC64 16 User Manual IC64 16_UM_141204 Page 14 of 53 PSI System Controls and Diagnostics 220 m 2X 120 0 2X 105 0 6 40 2X DARJE V 6 FIDUCIAL MARKED D 2X 35 0 2X 20 0 t 2 M3X0 5 v 6 AX DIAS 050 V 6 LOCATING HOLE MARKED B OXMOox1 0 10 MOUNTING HOLE MARKED A 2X 5 05 VO LOCATING SLOT MARKED C aed ame 44 0 tae BETWEEN ENTRY amp EXIT WINDOWS 00 Figure 2 IC64 16 mounting face 2 1664 16 User Manual IC64 16 UM 141204 Page 15 of 53 PSI System Control
11. to keep the signal cables short for best noise performance but keep the electronics out of the radiation field A maximum cable length of 10 m 33 is recommended Longer cables will still function but signal to noise performance will degrade with length Low noise signal cables are recommended to minimize noise due to cable movement and vibration although good quality conventional screened cables may suffice in some cases Low noise cables are available to special order from Pyramid Technical Consultants Inc 9 3 3 Readout with the 1128 electrometer The Pyramid 1128 electrometer provides 128 channels of signal processing for the strips one integral plane readout a high voltage bias supplies giving up to 2 kV high voltage readback sensing and readout of one set of environment monitors The 128 can perform the same real time computations on the data as the 16400 and it has a set of digital and analog I O and interlock relays that can be used to control a beam delivery system If you require independent biasing and readout of the second integral plane in the IC64 16 then you will require a single channel electrometer In the following schematic the F100 electrometer performs this role with a data connection via the 1128 but any suitable device can be used and it may be completely independent The only constraint is that electronic units must share a common ground this will be ensured by the HV cable screens 1064 16 User Manual IC64 16 U
12. 204 Page 48 of 53 PSI System Controls and Diagnostics Noise in readout in the 20 300 Hz range Noise pulses on signals IC64 16 User Manual HV arcing due to high humidity HV arcing due to very high local beam intensity Triboelectric noise in signal cables IC is responding to loud audio noise in the environment Interference from external electrical equipment such as motors AC magnetic field pickup are in place Perform HV bias enable pulse check Check humidity sensor Check enclosure is sealed desiccant chamber O ring gas flow plugs Check beam current and IC signal level Ensure cables are not moving or vibrating wait and recheck Turn off noise source and recheck Turn of potential noise sources and recheck Disable AC electromagnets and recheck IC64 16 UM_ 141204 Pyramid Technical Consultants Change desiccant if required Remake any seals as necessary and check that internal humidity drops below 10 Operate within the beam current density limits of the IC Reduce the bias voltage Remove source of vibration or movement and or use low noise cables Do not use data from immediately after any movement of cables Move noise source away Filter out problematic frequencies Shut down noise sources when making measurements Route cables well clear of stray magnetic fields Route cables through magnetic shielding ducts Page 49 of 53 PSI
13. 3x8 screws tightening the screws evenly to ensure the seal is well made 8 Remove protective window covers if you fitted them at the start of the process 9 Monitor the two humidity readbacks from the IC64 16 One of the sensors is close to the desiccant and its reading should drop below 10 relative humidity in less than one hour Allow 12 hours for the second sensor to also drop below 10 If this does not happen then the replacement desiccant was already saturated or there is a break in in the hermetic seal of the IC 1064 16 User Manual IC64 16 UM 141204 Page 46 of 53 PSI System Controls and Diagnostics 13 3 Consumables and spares Supplier Desiccant replacement set three sachets DES _PK_ C64 Pyramid Technical Consultants Tri Sorb 5G 4A G2 27X70 Matl 4286 Inc O ring SVPV1000 1 78x 175 26 for 11205531 1t 16 Pyramid Technical Consultants desiccant chamber cover Inc 1664 16 User Manual IC64 16 UM 141204 Page 47 of 53 PSI System Controls and Diagnostics 14 Fault finding The IC64 16 is designed to give you trouble free service We expect that a simple replacement policy will be followed for any units that fail on a beamline and that failed units will be returned to Pyramid for refurbishment However the following fault finding is provided to help decide whether an IC should be exchanged and to guide repairs for customers who do not have a service arrangement Beam position peaks Connections from IC
14. 7 146 39 KGnd Strip 41 140 1664 16 User Manual IC64 16 UM 141204 Page 41 of 53 PSI System Controls and Diagnostics 12 1 3 Environment sensors Two DSub 9 pin male Pin 1 Pin 5 Pin 6 Pin 9 External view on connector solder side of mating plug 1 Chassis Analogout 3 Digital in 2 switch control bit 1 8 Digital out 2 QD bit2 4 Digitaloutl Dbitl 9 Vrefin S O Pin 2 is connected internally to DGnd by the signal selection switch Pins 4 8 allow the external electronics to identify the configuration of the ionization chamber Internal links pull them to ground to set the ID bit 12 1 4 High voltage inputs and outputs Four SHV receptacles To mate with standard SHV connector Inputs and outputs both connect to the relevant anode internally at independent points 12 2 Fill gas Push fit fittings are installed for 1 8 flexible tubing Gas in and out are not distinguished and are interchangeable If using the chamber with air filling the plugs must be fitted to seal the chamber ae i la 1d E E e E i Figure 23 Plugging flow gas port for operation with dry atmospheric air 1064 16 User Manual IC64 16 UM 141204 Page 42 of 53 PSI System Controls and Diagnostics 13 Maintenance CAUTION Radiation Do not work in the beamline area or on the C64 16 until a survey has been completed by a qualified radiation supervisor a
15. Check connections Correct cabling use distorted and change to electronics are carefully color coding to discontinuously with mixed up simplify installation beam position Cables do not connect Check cables and Use correct cables each strip to drawings carefully Use electronics that corresponding allows pin to pin electronics channel cables as this is simpler to diagnose Beam position peak IC is rotated so that Check IC orientation Change orientation or moves in wrong axis direction sense is make sign correction direction when the altered in position calibration beam moves Position calibration Check IC orientation Use correct factor gain has the wrong and calibration sign factors PO E E Small or no signal HV is not enabled or Check power supply Correct as necessary connected and cabling HV bias not reaching Check loopback HV Correct as necessary the relevant anode if this is used If the lost connection Check HV supply is inside the IC Check cable contact Pyramid integrity Technical Consultants No signal from HV not applied across Check connections Correct the integral plane the relevant gap connections Consider swapping the HV connections if this is causing confusion Unstable signal Internal electrode is Check external Correct any floating connections to connection errors If electrometer inputs you suspect an internal and HV bias supplies break contact 1664 16 User Manual IC64 16 UM 141
16. I System Controls and Diagnostics enabled The channels giving the largest response are those opposite anodes refer to section for information about which readout electrodes face which anodes Every channel should show a transient response as the HV comes on and the individual strips on an electrode should show similar response If any channel that does not respond that can indicate that it has become disconnected Check that the electrometer and external wiring is good before suspecting a break inside the chamber 13 1 2 Offset currents In the absence of a particle beam or any electromagnetic or triboelectric noise sources there will a characteristic pattern of small background currents which you can see clearly using a long integration or averaging period in the electronics If you keep a record of those currents you can spot any trends or discontinuities which may indicate an emerging problem Two adjacent strip channels that start to show diverging offset currents can indicate a high resistance short between them A sudden change or a trend on one channel can indicate an open circuit or high resistance has developed somewhere in the connection of the electrode to the electrometer 13 2 Desiccant replacement The desiccant should be replaced if the reading from the internal humidity sensor starts shows greater than a few percent relative humidity 10 is the upper limit for reliable operation The procedure can be carried out with
17. IC64 16 Ionization Chamber User Manual Pyramid Technical Consultants Inc 1050 Waltham Street Suite 200 Lexington MA 02421 USA US TEL 781 402 1700 FAX 781 402 1750 EMAIL SUPPORTOPTCUSA COM Europe TEL 44 1273 492001 PSI System Controls and Diagnostics 10 11 Contents CONTENTS iia FIGURES Sun reia EEEE E ESES aaa SAFETY INFORMA TION os MODELS nidad ia lactea SCOPE OF SUPPLY ii ein eade aaa aaa aa oa aaaea OPTIONAL ITEMS AND CONSUMABLES seesseeesssssssosssssssoooossssssssosssess 6 1 READOUT ELECTRONICS 0 de 6 2 SIGNAL CABLES AND CABLE ACCESSORIES oocccooccnonoccnnoncnnnccnnnccnonaconaccnanicnns 6 2 1 Manda cables o O N E caus saian T N 6 2 2 CIES CIS ori a Gro TOONS UIA BEES usara aba alan ates INTENDED USE AND KEY FEATURES cccccccccoonnncccncononccnacicnnccnnnacananoss TL INTENDED US E rua ia reido Te EEY ES A a OO ANN A EA SPECIFICATION copia a INSTALLATION aa 9 1 PREPARATION AND HANDLING ocococccnonoconnnonccnnnacononoconononocnonanocnnnnocononanonnnns Dee MOUNTING rro Ea o conasa 9 2 1 Standard MOUNTING Arrangement ooooooonnnncnnnnnnnnnnnnnnnnnnnnnnnnnnncnnnnnnnnnos 9 2 2 Beamline coordinate CONVENTIONS ooccoonncnonncnnnnnnnnoronnnrcnnnrcnnnarananinnns 93 ACABLING AND SER VICES sas 93 1 Electrical CONNECITON Sd tds 9 3 2 Readout with the 16400 electrometeT ooonnncninnccnnnninnnnonnncnnnacinnananos 9 3 3 Readout with the 128 electrometer oonnnnnncinnnnicin
18. M 141204 Page 25 of 53 PSI System Controls and Diagnostics LAN A pS Anode 1 2 HV feed sense SHV Integral A signal Lemo OB 4 pin re E 2x32ch axis A _ signals HD44 1128 XP20 am l II O 2x32ch axis B Fiber comms signals HD44 Integral B signal Environment sensors D9 Trigger synch D9 D25 ST fiber adaptor A F100 XP20 Anode 3 HV feed sense SHV Figure 12 Schematic connection arrangement to one 1128 XP20 electrometer and an F100 In this arrangement the 1128 XP20 reads out and biases integral plane B and strip planes A and B The F100 XP20 biases and reads out integral plane B 9 3 4 Cable routing Ionization chambers create very small current signals so you must give careful attention to screening grounding and routing of cables Good grounding practice and the use of good quality screened cables will minimize noise injection by electrical coupling However it is possible to pick up interference from AC magnetic fields These may be present if the ionization chamber is operated in the vicinity of fast beam scan magnets or switching magnets The fields can induce small currents in the cables between the IC and the electrometer Because the ionization chamber appears as a capacitance between the signal lines and the ground return path the resulting interference on the si
19. PPORT lt lt eii 51 7 DISPOSA Laia da A Ai til 52 1S REVISTON TIS TOR Locarno dina 53 1664 16 User Manual IC64 16 UM 141204 Page 3 of 53 PSI System Controls and Diagnostics 2 Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Figure 26 IC64 16 User Manual 1C 64 16 dimensions mm and mounting face 1 ccccscsssssscsccccssssssscccccccsssssssscscccsssssssssscccsssesesseees 14 PCG4 16 MOUNTING TACO Lis labaneshacsuseradeincdwousaieatecsbaceshasancasedesetdscasseeaiaiesncesess 15 1C 64 16 connectors face nominal beam entry face cccccccrrrsssssccccccccssssssssccccscssssscsccccssesssssssccooes 16 AAA LN 17 IC64 i6 MOUNTING SUFLACES aiii IEA E a a Eaa a 19 Additonal Mountmo TEAUIEES odias eeraa ers S EE A RE AA EN ENEE ERAR 19 Beam entrance face in the standard orientation showing connection points ssssseesosssssceecocsssseeeooo 20 Sequence of electrode foils for nominal beam direction eesssssssseeccosssssececcossssececocssssececoossssseeeossssssee 21 Ion optics standard coordinate convention Transport code ssssssssececoossssccecccssssceecoossssceecosssssseesoo 22 Schematic connection arrangement to two 16400 XP20 electrometers cccccccss
20. SI System Controls and Diagnostics 12 Connectors 12 1 Electrical 12 1 1 Integral plane readouts Two Lemo four way female type OB EPG 0B 304 HLN To mate with Lemo FGG 0B 304 CLAD52Z or similar lo 04 20 03 External view on connector solder side of mating plug Chassis l and 3 are connected internally 12 1 2 Axis A and B signal outputs Two sets of two DSub 44 pin male color coded Pin 1 Pin 15 Pin 16 O O pee Pin 31 Pin 44 External view on connector solder side of mating plug Strip numbering assumes connection to the corresponding channel inputs of 16400 or 1128 electrometers via pin to pin cables Note that electrical schematics for the IC64 16 the 16400 and the 1128 number the strips and channels starting from O instead of 1 These references are shown as I_xx in the connector tables below 12 1 2 1 Strips 1 32 connectors A1 color code red and B1 color code blue Strip 31 130 6 Strip20_ 119 21 Strip21 120 8 Strip16 LIS 23 Strip17 16 38 KGnd 1664 16 User Manual IC64 16 UM 141204 Page 40 of 53 PSI System Controls and Diagnostics 9 Strip14 13 24 Suip 15 14 39 KGnd 12 1 2 2 Strips 33 64 connectors A2 color code green and B2 color code white 6 Strip52_ 151 21 Strip53 152 36 KGnd Strip 51 1 50 8 Strip48 147 23 Strip49 148 38 KGnd 9 Strip46 145 24 Strip4
21. System Controls and Diagnostics 15 Returns procedure Damaged or faulty units cannot be returned unless a Returns Material Authorization RMA number has been issued by Pyramid Technical Consultants Inc If you need to return a unit contact Pyramid Technical Consultants at support ptcusa com stating model serial number nature of fault CAUTION Radiation The unit cannot be shipped until it is certified to be below legal limits for radiation and that it is clear of any chemical contamination An RMA will be issued including details of which service center to return the unit to The unit must be returned in its original shipping case to avoid damage Figure 26 Ionization chamber in shipping case with protective window covers fitted IC64 16 User Manual IC64 16 UM 141204 Page 50 of 53 PSI System Controls and Diagnostics 16 Support Manual and other documentation updates are available for download from the Pyramid Technical Consultants website at www ptcusa com Technical support is available by email from support ptcusa com Please provide the model number and serial number of your unit plus relevant details of your application 1C64 16 User Manual IC64 16 UM 141204 Page 51 of 53 PSI System Controls and Diagnostics 17 Disposal We hope that the IC64 16 gives you long and reliable service The IC64 16 is manufactured to be compliance with the European Union RoHS Directive 2002 95 EC and as such should
22. e or rupture the windows The return line can be temporarily disconnected for initial flushing out atmospheric air to reduce backpressure 1C64 16 User Manual IC64 16 UM 141204 Page 27 of 53 PSI System Controls and Diagnostics 10 An Overview of the 1C64 16 10 1 lonization chambers 10 1 1 Signal formation High energy ions pass through matter with relatively small lateral scattering and energy loss but nevertheless leave a trail of ionization behind More than one ion electron pair is created per ion passing through so the chamber has gain The free charge that is created in the chamber gaps is separated by the applied bias voltage with the positive ions moving to the cathodes which are grounded at the virtual earths of the readout preamplifiers and the electrons or negative ions formed by electron capture moving to the anode The resulting small current is measured by the readout electronics The current from an individual ion 1s too small to measure but for beam currents of a few 10 s of pA or more the aggregate current can be measured by sensitive electrometer electronics Cathode Anode Cathode Beam ion Pre amp Pre amp Figure 13 lonization chamber signal formation The ionization chamber uses parallel plate geometry to provide uniform gain over its active area At higher applied bias voltages and with field intensifying geometry such as thin wires or points the chamber would start operate in the proportional regime
23. e were to lead you to come into contact with them The user must therefore exercise appropriate caution when servicing the device and when connecting cables Power should be turned off before making any connections The body of the IC64 16 should be grounded via its connection to the customer s beamline and or mounting CAUTION Radiation After use in a high energy particle accelerator beamline the IC64 16 may become activated Do not work on the device or move the device from a controlled area until it has been surveyed and declared safe by a qualified radiation supervisor Only Service Personnel as defined in EN61010 1 should attempt to work on the disassembled unit and then only under specific instruction from Pyramid Technical Consultants Inc Some of the following symbols may be displayed on the unit and have the indicated meanings 1664 16 User Manual IC64 16 UM 141204 Page 5 of 53 PSI System Controls and Diagnostics Direct current Earth ground terminal Protective conductor terminal Frame or chassis terminal Equipotentiality Supply ON CAUTION RISK OF ELECTRIC SHOCK CAUTION RISK OF DANGER REFER TO MANUAL T a sl Y Supply OFF IN CAUTION ENTRAPMENT HAZARD 1064 16 User Manual IC64 16 UM 141204 Page 6 of 53 PSI System Controls and Diagnostics 4 Models IC64 16 Transmission ionization chamber with two orthogonal 128 strip readout electrodes and two integral dose plane electrod
24. emo OB 4 pin i O p amp d 6 E 2x32ch axis A signals HD44 16400 XP20 2 LAN oar Env sense Lemo OB 4 pin 2x32ch axis B signals HD44 IC64 16 64 channe o Anode 1 2 HV feed sense SHV Figure 10 Schematic connection arrangement to two 16400 XP20 electrometers If you wish to avoid a possible source of confusion when fault finding then you can make a crossed connection of the HV bias cables as shown in figure 11 With this cabling the assignment of functions is as follows Readout electrode Biased by Read by Integral A Strips A X Integral B Strips B Y IC64 16 User Manual IC64 16 UM 141204 Page 24 of 53 PSI System Controls and Diagnostics LAN Anode 3 HV feed sense SHV Environment sensors D9 D9 D25 adaptor 16400 XP20 1 Ty E omc zg Trigger synch Integral A signal Lemo OB 4 pin i O p amp d 6 E 2x32ch axis A signals HD44 16400 XP20 2 LAN Can Integral B signal Env sense Lemo OB 4 pin 1064161 TS Chan 2x32ch axis B signals HD44 Anode 1 2 HV feed sense SHV Figure 11 Schematic connection arrangement to two 16400 XP20 electrometers HV crossed The location of the 16400s must reconcile the conflicting requirements
25. es 1064 16 User Manual IC64 16 UM 141204 Page 7 of 53 PSI System Controls and Diagnostics 5 Scope of Supply 164 16 model as specified in your order USB memory stick containing 1C64 16 Data sheet 1C64 16 User manual Test data Gas port plugs High quality shipping case Optional items as specified in your order 1064 16 User Manual IC64 16 UM 141204 Page 8 of 53 PSI System Controls and Diagnostics 6 Optional Items and Consumables 6 1 Readout electronics 16400 XP20 64 channel electrometer with integral plane readout channel and 2kV bias supply Two required to read out one IC64 16 1128 XP20 128 channel electrometer with integral plane readout channel and 2kV bias supply One plus one independent readout and bias for second integral plane required to read out one IC64 16 6 2 Signal cables and cable accessories 6 2 1 Individual cables CAB D44F 25 D44M Cable 44 way screened DSub 44 pin female to DSub 44 pin male 25 7 6m Four needed per C64 16 Other lengths available CAB D44F 20LN D44M Cable 44 way screened with anti triboelectric layer DSub 44 pin female to DSub 44 pin male 25 6 1 m Alternative to standard cable four needed per IC64 16 Other lengths available CAB L304M 25LN L304M Cable 4 way screened with anti triboelectric layer Lemo 304 4 pin male to Lemo 4 pin male 25 7 6 m Two needed per IC64 16 Other lengths available CAB SHV 25 SHV Cable coaxial HV SHV to SHV 25
26. f the electrons will be captured by electronegative gas molecules such as O2 The resulting negative charge carriers move at similar speed to the positive ions Overall a time resolved measurement of the IC signal shows a sharp initial spike due to electron movement varying from 50 to 0 of the whole depending on the electron capture fraction plus a slow tail due to the ion drift The simulated example in figure 15 shows a case for a 3 mm gaps where the beam pulse is less than one microsecond and two thirds of the electrons are converted to negative ions The time axis is expanded on the right 7 OE 04 7 OE 04 6 0E 04 6 0E 04 5 0E 04 5 0E 04 4 0E 04 4 0E 04 3 0E 04 3 0E 04 lt x c w o 2 IC current A 2 0E 04 2 0E 04 1 0E 04 1 0E 04 0 0E 00 0 0E 00 o o o o o o o o o o t N N t WO 00 o N 1 H aag Time us Time us sum e sum er Figure 15 Example simulated pulsed beam response Generally you require the total charge measured by the 10n chamber for dosimetry purposes so the electronics should be set up to trigger prior to the start of the pulse and to integrate until all the ions have been collected However the fast electron signal component can be useful for triggering purposes Note that even if you are making measurements on DC beams the ion collection time limits the speed of response to changes for example to the particle beam being suddenly turned off 10 1 3 Gain calibration
27. g flow gas port for operation with dry atmospheric air sccssscscccccsssssssscccccsccsssssssccooes 42 Desiccant chamber locaON coacciones e aE AESA suedaetasiaseatieesioteancsscateens 45 Desiccant sac replacement components csssscccccccrssssssscccccccssssssccccccsscssssssscccsssesssssscccsssssscssccooes 46 Ionization chamber in shipping case with protective window covers fitted sssscccccccsssssssees 50 IC64 16 UM 141204 Page 4 of 53 PSI System Controls and Diagnostics 3 Safety Information This unit is designed for compliance with harmonized electrical safety standard EN61010 1 2000 It must be used in accordance with its specifications and operating instructions Operators of the unit are expected to be qualified personnel who are aware of electrical safety issues The customer s Responsible Body as defined in the standard must ensure that operators are provided with the appropriate equipment and training The unit is designed to make measurements in Measurement Category I as defined in the standard CAUTION High voltage High voltage must be provided to this device for correct operation The high voltage is not exposed in the correctly assembled unit Two independent voltages of up to 2000 V DC at 500 uA maximum can be supplied to the IC64 16 via the SHV connectors The are not accessible or hazardous live under the definitions of EN61010 but may nevertheless give a noticeable shock if misus
28. gnal appears as a differentiated version of the changing field multiplied by a gain term related to the absolute field level This gain factor arises from yoke saturation in the source magnet s leading to a non linear increase in their stray fields If you observe interference like this you should re route the cables away from regions where a high stray magnetic field is present As a further measure the cables should be run in ducting that provides magnetic shielding made of a high permeability material like soft iron or mu metal 9 3 5 Gas connections The following service connections are required if you plan to use flow gas filling 1064 16 User Manual IC64 16 UM 141204 Page 26 of 53 PSI System Controls and Diagnostics Fill gas in optional Push fit connector for 1 8 flexible tubing Fill gas out optional Push fit connector for 1 8 flexible tubing The IC64 16 can be operated with dry air filling in which case the plugs in the two gas connectors must be kept in place If you wish to use flow gas then one connector will be the input and the other the output The gas in and out ports are interchangeable Use clean 1 8 OD flexible pipe There should be sufficient length on the return line to inhibit migration of atmospheric air back into the IC body CAUTION Risk of damage by overpressure The required flow rate for flow gas operation is very small Take great care not to overpressure the IC64 16 which could damag
29. igh beam currents to be measured e Operation with atmospheric air or flow through gas e Bias voltage up to 2 kV e Independent biasing of the two integral plane electrodes e Bias voltage loopback e Hermetically sealed with built in desiccant 1664 16 User Manual IC64 16 UM 141204 Page 10 of 53 PSI System Controls and Diagnostics e Integrated redundant sensors for temperature pressure and humidity e Compatible with the 16400 and 1128 electrometers 1064 16 User Manual IC64 16 UM 141204 Page 11 of 53 PSI System Controls and Diagnostics 8 Specification Beam compatibility Protons deuterons helium ions carbon ions Energy range 30 MeV nucleon to 500 MeV nucleon Beam current density Up to 30 nA cm protons The limit is not fixed but depends upon how much recombination is tolerated The amount of recombination can be modified by selection of high voltage setting and gas fill Sensor Type Parallel plate dual ionization chamber with two multistrip cathodes and integral plane dose cathode Sensitive volumes Anode 1 to integral cathode 1 3 mm Strip cathode 1 to anode 2 5 mm Anode 2 to strip cathode 2 Smm Integral cathode 2 to anode 3 3 mm Readout strip geometry 64 strips equal width 2 4 mm on 2 50 mm pitch Better than 2 for beams within the sensitive area Position accuracy Integral linearity better than 60 um maximum deviation relative over the sensitive area Depends on signal
30. ition relative to IC body must be adjusted by this offset IC64 16 User Manual IC64 16 UM 141204 Page 35 of 53 PSI System Controls and Diagnostics Figure 21 Displacement of IC body coordinates red from IC strip electrode coordinates blue Finally we change to beamline coordinates For the example we assume this involves a change in the X axis direction and a further measured residual offset AX of the IC body relative to the beamline stated in the beamline coordinate system T ENI SCT NAAA AXo Me 1 64 Figure 22 Change to beamline coordinates green Thus the beam position in beamline coordinates is Xp MXs AXo AX 1064 16 User Manual IC64 16 UM 141204 Page 36 of 53 PSI System Controls and Diagnostics where A 1 if the IC X axis is in the same direction as the beamline X axis and A 1 if it is in the opposed direction 10 2 2 Beam width Conversion of computed beam width to physical units is simply a matter of multiplying the width computed in strips to mm by multiplying by the strip pitch S 1064 16 User Manual IC64 16 UM 141204 Page 37 of 53 PSI System Controls and Diagnostics 11 Environment sensors 11 1 Readout The IC64 16 includes two identical circuit boards that route signals to the external connectors Each also includes sensors for the temperature pressure and humidity of the gas filling A redundant measurement of each is therefore available The signals are read out as voltages by exter
31. nal electronics such as the 128 electrometer and converted to physical units using the calibrations given in the next section All three voltages plus the reference voltage provided by the external electronics are connected to a single analog channel via an on board multiplex switch The switch is controlled by a pair of digital lines a Temperature Vmes 0 1 Pressure Vmep ooo _ Relative humidity Vmes The signals change only slowly The readout electronics can and should use long averaging periods gt 0 1 second recommended to give good signal to noise ratio 11 2 Calibrations 11 2 1 Temperature Convert the raw voltage V measr from the sensor to temperature as follows Temperature centigrade 100 Vineast Temperature Kelvin Temperature centigrade 273 2 11 2 2 Pressure Convert the raw voltage V measp from the sensor to pressure as follows Pressure psi 18 75 Vineasp Vref 0 1 Pressure mbar Pressure psi 68 95 Pressure Pa Pressure psi 6895 Vier 1S the reference voltage supplied by the external electronics and is 5V nominal The voltage supplied by the 1128 electrometer is 5 V 1664 16 User Manual IC64 16 UM 141204 Page 38 of 53 PSI System Controls and Diagnostics 11 2 3 Humidity Convert the raw voltage V measu from the sensor to relative humidity as follows Relative humidity 157 V measu Vref 23 8 1064 16 User Manual IC64 16 UM 141204 Page 39 of 53 P
32. nd 30 nA cm recombination is negligible and can be safely ignored Even at higher current densities the effect on the measurement of the beam centroid and width is comparatively little affected The following plots show an beam profile measurements made with a chamber with 10 mm gaps for 228 MeV protons at beam current 2 7 nA and 18 4 nA The bias voltage setting was 2 kV The approximate beam current density at the peak was 12 and 80 nA cm The peak channel response is suppressed by 10 due to recombination but the centroid determination altered by only 0 02 mm and the width determination by 0 09 mm IC64 16 User Manual IC64 16 UM 141204 Page 33 of 53 PSI System Controls and Diagnostics 2 0E 11 1 0E 10 1 5E 11 7 5E 11 1 0E 11 5 0E 11 5 0E 12 2 5E 11 0 0E 00 0 0E 00 Figure 19 Example of minimal effect of recombination on peak measurement Because the peak shape determination remains robust it is possible to make a first order correction of the measured current or charge for moderate recombination amounts using knowledge of the beam dimensions to estimate the local current density 10 2 Position readout The strip pitch of the IC64 16 S 2 50 mm is relatively small compared to the beam width for the intended application so that you will see signal on three strips at least You can then use peak fitting or center of mass calculation to determine the position of the peak to much less than one strip width typically 10
33. nd the radiation is known to be at acceptable levels We do not recommend that you attempt to disassemble the IC64 16 There are no routine service parts inside and the risk of damage to delicate electrode structures 1s high Pyramid Technical Consultants offers a complete factory refurbishment service 13 1 Preventative maintenance schedule Exact details will depend on the nature of your application If the 1128 25 is being used in a critical dosimetry application then validation against external traceable standards will be required on a regular basis frequency duration Check dose Daily 1 hr Follow procedures defined your calibration against facility QA standard Check response to Daily 2 min Record signals on all channels as HV HV enable pulse is enabled All channels should respond Look for any trends Check offset Daily 5 min Record background offset on all currents channels with HV on beam off no known electrical noise sources active Look for any trends Replace desiccant 30 min Replace desiccant packs four per dehumidification chamber time 13 1 1 HV enable response check This is a powerful diagnostic of all readouts that can be performed quickly and regularly When the HV bias is applied to the chamber the capacitances of the electrode stack are charged up and current flows while this is taking place Acquire data on all channels while the HV is being 1664 16 User Manual IC64 16 UM 141204 Page 43 of 53 PS
34. nninnnnonanccnnnicinannnnns TIA COLE SOU A E A Ba adh ess ee 935 AG GS CONNECH ONS A A saa Givtudteiates AN OVERVIEW OF THE I 064 16 ccccccssscccssscccssssssccssccccssssscccses 10 1 IONIZATION CHAMBER Sd acia 10 1 1 Sendal Trmal ON SA AEA 10 1 2 Fused Dea aar T adn 10 1 3 GOMERA daa 10 1 4 Effect of DEG TIA ECLOLY A AA 10 1 5 RECOMIENDA 10 2 POSITION READOU E aida 10 2 1 DENCIA diia 10 2 2 Peame Wide a a a aos ENVIRONMENT SENSORS naniesienia eaae aeai 11 1 JAEN 4B 108 KADEER A enn e o la IC64 16 User Manual IC64 16 UM 141204 Page 2 of 53 PSI System Controls and Diagnostics 11 2 CALIBRATION Roce en eee a as ae eo ME 38 11 2 1 ATAN hel cae senate tsa hee aang eT eta AG AG ae 38 11 2 2 EA E AVENO EN E A AE VNE O AAN E A E ESA A A A 38 11 2 3 nn A yg O AA 39 12 CONNECTORS eras 40 e PCIE cone nen meme Re NE REC BO te RE OD TR ET decias 40 12 1 1 METE OUT TCA AOS ake tics eh has SA A sain as tesa ecoedee rR 40 212 AXES AONE BANA OULD US AAA A AA A A an 40 12 1 3 FOREM SENS OIS a aE sado 42 12 1 4 TLV VOU SE INDUTS IRNOS cia 42 12 2 AS a A O E E O O suheadeds 42 IS MAINTENANCE iia A E A ias 43 13 1 PREVENTATIVE MAINTENANCE SCHEDULE ud tas 43 13 1 1 HVienable response CC Ok at IA LA T O E 43 13 1 2 OSCE CUI TCI S Aaa ds 44 13 2 DESICCANT REPLACEMENT ados 44 Y da A A EEC 44 13 3 CONSUMABLES AND SPARE S aaa a ele unn Ese a 47 EA EAUL T FINDING A O 48 TS RETURNS PROCEDURE ostia dd oca 50 to SU
35. not present any health hazard once any activation has decayed CAUTION Radiation The IC must not be released from a radiation controlled area until it has been surveyed and declared safe by a qualified Radiation Supervisor When your IC64 16 has reached the end of its working life you must dispose of 1t in accordance with local regulations in force If you are disposing of the product in the European Union this includes compliance with the Waste Electrical and Electronic Equipment Directive WEEE 2002 96 EC Please contact Pyramid Technical Consultants Inc for instructions when you wish to dispose of the device 1C64 16 User Manual IC64 16 UM 141204 Page 52 of 53 PSI System Controls and Diagnostics 18 Revision History The release date of a Pyramid Technical Consultants Inc user manual can be determined from the document file name where it is encoded yymmdd For example BIO_UM_080105 would be a B10 manual released on 5 January 2008 IC64 16_UM_ 141204 First general release 1664 16 User Manual IC64 16 UM 141204 Page 53 of 53
36. onization chamber becomes important The cloud of ion electron pairs is produced essentially instantaneously by the passage of the high energy beam particle but signal development only starts as the ions and electrons start to drift in opposite directions in the constant applied electric field The mobility of ions in air in the chamber electric field is about 30 m s 1 at 1000 V bias and 1 atmosphere pressure and it varies directly with electric field and inversely with gas pressure Thus it takes about 150 usec to collect all ions created in a 5 mm gap and about 100 usec in a 3 mm gap The mobility of free electrons is hundreds of times higher for example 13400 m s 1 for 1000 V bias and atmosphere pressure so electrons should be collected in less than 1 usec under these conditions The variation with field and pressure is more complex than for ions but higher fields and lower pressures again increase mobility Other gas mixtures can have much higher or lower mobilities Hydrogen and helium give high mobilities water vapour reduces ion mobility significantly The motion of the electrons and ions in the chamber field produces changing charges on the electrodes which are the detectable signal If electrons remain free then 50 of the signal should appear very quickly with the other 50 developing until all the ions are collected IC64 16 User Manual IC64 16 UM 141204 Page 29 of 53 PSI System Controls and Diagnostics However some fraction o
37. onsistent across the chamber 150 Proton energy MeV Figure 16 Approximate gain curve for the IC64 16 protons in air at SATP 50 300 MeV IC64 16 User Manual IC64 16 UM 141204 Page 31 of 53 PSI System Controls and Diagnostics Proton energy MeV Figure 17 Approximate gain curve for the IC64 16 protons in air at SATP 100 250 MeV Since the gain at any beam energy is a function of the gas density in the electrode gaps it has to be corrected for variation in pressure and temperature relative to the gain at some reference pressure and temperature where it is known For example if you know the gain at standard atmospheric temperature and pressure SATP Temperature_satp 298 15 K Pressure_satp 100000 Pa then the actual gain for another air pressure and temperature is given by Gain_actuaL Gain_satp 1 Pressure_satp Pressure_actuat Temperature_actuat Temperature_satp Temperatures must be in Kelvin pressures can be in any convenient absolute unit 10 1 4 Effect of beam trajectory The gain parameter assumes that the beam passes through the detector orthogonal to the electrode planes If the beam passes through at an angle then the ionized gas path is longer and thus a higher signal is produced The strip readout will also see a broadened peak 1064 16 User Manual IC64 16 UM 141204 Page 32 of 53 PSI System Controls and Diagnostics Cathode Anode Cathode 3 gt gt 47 f _ e 4
38. r biased should be fitted with shorting plugs 9 3 2 Readout with the 16400 electrometer Any suitable electronics system can be used to read out the IC64 16 The Pyramid 16400 electrometer is well suited intended to read out the IC64 16 however Two 16400 XP20 are required per IC64 16 This provides 128 channels of signal processing for the strips two independent integral plane readouts two high voltage bias supplies giving up to 2 kV high voltage readback sensing and readout of both sets of environment monitors The 16400 can perform various real time computations on the data and it has a set of digital and analog I O and interlock relays that can be used to control a beam delivery system The following figure shows a connection arrangement Note that the biasing and readout of the integral plane electrodes are on different 16400s with this arrangement Generally this would be hidden in the way the controls and readbacks are presented in a user interface screen If the upper 16400 in the figure 1s labeled 1 and the lower 16400 2 then the assignment of functions as follows Readout electrode Biased by Read by Integral A Strips A X Integral B 2 Strips B Y 1664 16 User Manual IC64 16 UM 141204 Page 23 of 53 PSI System Controls and Diagnostics LAN Anode 3 HV feed sense SHV Environment sensors D9 D9 D25 adaptor 16400 XP20 1 Trigger synch Integral A signal L
39. recommend keeping the window covers on until the C64 16 is installed in its operating position in a clean dry area The windows can resist moderate pressure from fingers but could be punctured by sharp objects like hand tools Excessive inward pressure on the windows may allow the window to push on the active electrodes inside which may degrade gain uniformity Any service work must be carried out in a clean dry environment 9 2 Mounting 9 2 1 Standard mounting arrangement The IC64 16 should be mounted with its electrode planes orthogonal to the particle beam direction The beam may enter on either face and the IC may be mounted in any rotational orientation relative to the beam axis In most particle beam systems there are relatively independent X and Y axes orthogonal to the beam direction defined by the ion optical elements like dipole magnets and the IC will be positioned so that its two sensing directions align with X and Y The mounting must be aligned accurately with the beamline ion optical elements that define X and Y be rigid and not subject to vibration You may require that the mount provides position adjustment in the two transverse axes so that the IC transverse position can be adjusted to remove physically any offsets However a simple arithmetic offset correction by software is generally sufficient It is simpler to make a fixed mount compact and rigid 1664 16 User Manual IC64 16 UM 141204 Page 18 of 53 PSI
40. rode foils for nominal beam direction Note that the HV bias voltage input that corresponds to an integral plane electrode is on the other connector bank to the signal connection to that plane This is due to internal wiring constraints While this has no real operational consequence when the chamber is operating normally it may confuse fault finding so you may wish to correct this in the external connections as shown in section 9 3 1064 16 User Manual IC64 16 UM 141204 Page 21 of 53 PSI System Controls and Diagnostics 9 2 2 Beamline coordinate conventions In the conventional beamline optics convention as used by Transport and related codes z is always directed along the beam forward direction thus tangent to beam trajectory when in a dipole field the horizontal X axis is defined as orthogonal to z and outwards along the radius of curvature of local dipole magnets and vertical Y axis being the orthogonal direction to Z and X and thus the non dispersion direction of dipole magnets This is illustrated in figure 9 Note that this convention makes the X direction sense opposite to that shown in figure 7 Check carefully to ensure you know how the IC orientation you use relates to your coordinate system convention Bending by dipole magnet gt Figure 9 Ion optics standard coordinate convention Transport code 9 3 Cabling and services 9 3 1 Electrical connections The following cable connections are required
41. s and Diagnostics 282 0 222 0 GAS FITTING 1 8 TUBE ROTATABLE AV INPUT amp MONITOR SHV STRIP OUTPUT 64 CHANNELS AXIS HD 44 A A DOSE OUTPUT LEMO 0B ENVIRONMENT CONTROL 8 OUTPUT DB 9 GAS FITTING 1 8 TUBE ROTATABLE Figure 3 IC64 16 connectors face nominal beam entry face 1664 16 User Manual IC64 16 UM 141204 Page 16 of 53 PSI System Controls and Diagnostics STRIP ELECTRODE pitch 2 5 mm strips parallel to paper in this view IT E q E rl S ESA SS uE En Y EH io Le Bl 3 INTEGRAL PLANE HV PLANE BOTH SIDES INTEGRAL PLANE SECTION A A STRIP ELECTRODE pitch 2 5 mm strips perpendicular to paper in this view Figure 4 Section on figure 3 1664 16 User Manual IC64 16 UM 141204 Page 17 of 53 PSI System Controls and Diagnostics 9 Installation 9 1 Preparation and handling The IC64 16 is shipped in a special protective transport case The interior gas volume is hermetically sealed and maintained at near zero humidity by the built in desiccant Open the case and check the IC on receipt but leave it in the case for protection until you are ready to use it Remove the unit carefully from the case taking care not to strain the gas connectors Leave the covers that protect the windows in place The IC is not heavy but it is delicate and must be handled carefully CAUTION Delicate equipment We
42. sssssssccccccssssscees 24 Schematic connection arrangement to two 16400 XP20 electrometers HV crossed scessseee 25 Schematic connection arrangement to one I128 XP20 electrometer and an F100 ccceeeees 26 Ionization chamber signal formation ssssssssececccsssscceccocssseccccossssececocssssseceocssssseecocossssceeecossssseeeossssssee 28 Signal Partition on Strip CATNOGES ccssscccsccvsvcsesecccescacceueeetedececeoessecsssevonwsosessedeccesouesseedcesousesseeseassencoessecees 29 Example simulated pulsed beam response sssssssececccssssscecccsssssececcssssscceccssssseccoosssssscecssssssseeessssssseesso 30 Approximate gain curve for the IC64 16 protons in air at SATP 50 300 MeV ssssssssssssseseee 31 Approximate gain curve for the IC64 16 protons in air at SATP 100 250 MeV sscsssssssssssseeee 32 Increased path length and ionization from an inclined trajectory seccccsssssceccccssssceccocsssseceecssssssee 33 Example of minimal effect of recombination on peak MeasureMent cccccccccrscrssssssssscssccccccccsssees 34 Beam position in 1C64 16 strip electrode coordinates blue ssssseccccssssscccccossssccecosssssccecosssssseesoo 35 Displacement of IC body coordinates red from IC strip electrode coordinates blue 04 36 Change to beamline coordinates green cccccccrsssssssscccccsssssssscccccccsssssscsccccsscssssscscccsscssssssssccssseeees 36 Pluggin
43. the IC64 16 mounted on the beamline or removed to a clean working location 13 2 1 Procedure 1 Perform a radiation survey to confirm that it is safe to work on the ionization chamber 2 Fit protective covers over the IC windows if they are liable to be touched while you are working on the IC 3 Locate the desiccant chamber 1664 16 User Manual IC64 16 UM 141204 Page 44 of 53 PSI System Controls and Diagnostics Figure 24 Desiccant chamber location 4 Remove the ten M3x8 screws If you are working with the C64 16 in situ then take the desiccant chamber to a clean working area Ensure that no dust contamination or parts can enter the chamber while the chamber is removed 5 Remove the eight M2 5x4 screws and washers that hold the wire grille to access the desiccant sacs Remove the three old desiccant sacs Remove the new desiccant from its sealed packaging ensure the three replacement sacs are clean and free of dust Place them in the recesses chamber IC64 16 User Manual IC64 16 UM 141204 Page 45 of 53 PSI System Controls and Diagnostics 10x M3 8x M2 5 Sealing face O ring A Hs y Chamber with Grille 3x desiccant recesses sac Figure 25 Desiccant sac replacement components 6 Refit the grille using the M2 5x4 screws and washers and ensure that the O ring is clean and correctly positioned 7 Check that the O ring sealing surface on the IC body is clean and refit the cavity to the IC body with the M
44. to noise ratio 10 s of um achievable Fiducials Electrode strips tolerance buildup relative to fiducial features on body 0 3 mm nominal lt 0 1 mm typical HV bias range Up to 2000 V nominal 3000 V maximum HV configuration Two independent bias voltage inputs each with loopback of voltage for validation Beampath materials Layers 12 5 um polyimide window with 0 1 um Al both sides window 13 9 mm fill gas 12 5 um polyimide with 0 1 um Al both sides anode 1 3 0 mm fill gas active volume 25 um polyimide with 0 1 um Al both sides integral strip pattern 5 0 mm fill gas active volume 12 5 um polyimide with 0 1 um Al both sides anode 2 IC64 16 User Manual IC64 16 UM 141204 Page 12 of 53 PSI System Controls and Diagnostics NE Gas fill Humidity free air semi sealed operation or flow gas Desiccant Three desiccant sacs field replaceable 44 0 mm window to window 50 4 mm body face to body face Orientation Operable in any orientation and with beam entering in either direction Push fit self sealing to suit 1 8 plastic tube 3 8 kg 8 lb excluding an added mounting brackets Operating environment Clean and dust free 5 to 35 C 15 to 23 C recommended lt 70 humidity non condensing 5 0 mm fill gas active volume 25 um polyimide with 0 1 um Al both sides strip integral pattern 3 mm fill gas active volume 12 5 um polyimide with 0 1 um Al both sides anode 3 13 9
45. ystem we must first allow for any rotations of the IC relative to the beamline coordinate system due to the way it is mounted There will also be a series of small offsets which combine to give an overall offset between the position measured by the IC in its own strip electrode coordinate system and the corresponding position in the external coordinates The components of this series include the very small offset between the IC electrodes and the IC body the position of the IC relative to something that it is mounted to typically the accelerator beamline magnets determined by survey and position of the target of beam delivery relative to the beamline Offsets of the IC body relative to its ideal position in the beamline coordinate system will be determined during beamline survey The following example with grossly exaggerated offsets shows how a measured X position in strip electrode coordinates is translated to the beamline coordinate system Firstly the raw centroid Xs is found in the sensor coordinate system from the cathode strip signals using a suitable centroid calculation 1 64 Figure 20 Beam position in IC64 16 strip electrode coordinates blue The residual offsets between the strip electrodes and the body of the IC64 16 are controlled to less than 0 1 mm by the manufacturing process However if we know and wish to make adjustment for the small offset AXo between the strip electrode and the IC body then the beam pos
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