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D0 Clean Room ODH Analysis

Description: Table A shows the steady state situation. One ofthe two dewars would be supplying purge gas at (a maximum of) 20 scfm, which would leak: into the room through the welding orifice. Instantaneous uniform diffusion and exhaust are assumed. Note the probability is 1 for the 20 scfm leak since it is a planned occurrence. Table B is the same situation in the event of a power failure, estimated for twice a year (2.29 x 10{sup -4} fails/hour). This assumes that the exhaust is shut down, and the dewars are not turned off. This would require the minimum exhaust to be the same as the leak: (as an approximation). These results, however, would only be valid for an infinite supply of the purge gas, and for an exceedingly long power failure. Since the supply of LAr would only last a day at most, and the power failure would not last for weeks, this result has no real significance. In fact, the time constant for the ODH equation in this case is 5717 minutes, which means it would take 20 days for all the oxygen to be displaced. A worst case scenario would be a full dewar completely emptying into the clean room in a short time relative to the ventilation rate, but slow enough for uniform dispersion. We can do a leak/exhaust independent (ventilation rate=O) analysis. This also assumes instantaneous and uniform mixing. This suggests that even with a complete dewar failure, the oxygen content would not decrease to a safety hazard. The probability ofa simultaneous, catastrophic. dewar failure would be so low as to offset the consequences as insIgnificant, and even so. those consequences would be only a slight oxygen deficiency (17.5% 0{sub 2}) These same arguments could be followed for LN2 dewarst and would have the same results ...
Date: May 24, 1990
Creator: Michael, J.
Item Type: Report

D0 Clean Room ODH Analysis Instrument Air Considerations

Description: The ODH problem in this case involves the instrument air line to the clean room. which is isolated by a check valve from the gaseous nitrogen trailer backup source (valve CV787I, see DRG. NO. 3740.510-MA-273995, attached (the 'to purging enclosure' line nms to the clean room)). Normally, the check valve prevents backflow through the instrument air line. But as we all know, valves can fail. The estimated mean failure rate for a check valve to allow reverse flow is 3 {center_dot} 10{sup -7}. Failure of the instrument air and the check valve would allow the seepage ofgaseous nitrogen into the clean room. The failure of the instrument air is necessary to cause an ODH problem, due to the fact that the air pressure would keep the lower pressured gaseous nitrogen from flowing through the check valve. The compressor for the instrument air is fairly reliable, but to show the true nature of how safe this situation is, both cases that follow will assume that the compressor, and therefore the instrument air, has already failed. Table A shows the standard ODH situation. Assuming everything is working correctly (all the gasses are flowing, the ventilation is active, etc.), the only consideration is the failure of the check valve concurrent with the instrument air failure. The table clearly shows an ODH classification of 0, which would hold even for an extreme leakage, and which does not even consider the likelihood of the instrument air failure. which would lower the fatality rate even more. Note that the leak rate given in the tables following (50 scfm) is an overly generous amount considering the restricting nature of the small pipes and valve orifices. and that it is half of the compressor capacity. Table B is the same situation in the event of a power failure, ...
Date: January 14, 1991
Creator: Michael, J.
Item Type: Report

D0 Collider Detector LINDE, East Chicago (LAr Contractor) Trip Report

Description: East Chicago is capable of processing air at a 6-7E6 SCFH rate. They can produce as much as 1.2E6 SCFH 02 and 4.5 SCFH N2 (not coincidently) with a peak product efficiency of 85-86% (product to total Intake). The general area demand has been as high as 10E6, as low as 4.5E6, and is currently 8E6 SCFH totaI product. The plant is really four plants in one. At anyone time one or more plants can be down for maintenance and the others online and delivering to the pipe line that distributes their product to nearby steel plants, and to the liquid reservoirs (perlite insulated tanks) of 160, 160 and 200 E6 SCF. At the time of our visit two plants were down and two were on line. The following describes the characteristics of one of the four plants. The cycle requires a base compressor (Brown Boveri, 22,600 hp) that pumps to 90-100 psig, and a booster compressor (Clark, 14,000 hp) that pumps to 300 psig. Filter houses (ca. 20-ft x 20-ft) feed the suctions and the discharge is scrubbed by dual, molecular sieve, beds 0 300 psi (6-8 hour cycle time). The beds are provided with dust blow down and down stream filter provisions. The scrubbers remove CO2, the heavy HC, and water. The effectiveness of the scrubbers is measured by the record 6 years one of the plants ran w/o the need for thawing. The thaw operation takes about 4 days. It was interesting to learn that a plant can be brought on line in two and one half hours from a warm start. Major swings from N2 rich to O2 rich production take about an hour. Argon is a small constituent in air (0.61) and thus not a major product. It comes off the main column at 761 ...
Date: February 8, 1991
Creator: Dixon, K.; Krempetz, K.; Mulholland, G.T.; Urbin, J. & /Fermilab
Item Type: Report

D0 Collision Hall Outdoor Fresh Air Makeup

Description: This note will briefly describe the collision hall ventilation system and how D0 will monitor outside air makeup and what actions occur in the event of system failures. The Dzero collision hall has two different fresh air makeup conditions it must meet. They are: (1) Tunnel Barriers removed-Fresh air makeup = 4500 CFM; and (2) Tunnel Barriers in place-Fresh air makeup = 2800 CFM. This note demonstrates how the fresh air minimums are met and guaranteed. The air flow paths and ducts at D0 for both AHU1 and EF-7 are fixed. The blower throughputs are not variable. The software stops on AHU1's dampers will be set for a minimum of 2800 cfm or 4500 cfm of outdoor air continuously added to the HVAC flow stream depending on the tunnel barrier state. AHU1 and EF-7 both have monitoring that can determine reliably as to whether the respective blower is on or off. Since the outside air makeup is fixed as long as the blowers are running, and the software AHU1 damper limits are set, we can rely on the blower status indicators to determine as to whether the collision hall is receiving the proper amount of outside makeup air.
Date: March 27, 1992
Creator: Markley, D.
Item Type: Report

D0 Control Room Argon Test Cell Placement

Description: Due to the need of maintaining and providing high purity argon for the D0 experiment. it is necessary to have a purity verifying device readUy aVailable. The testing eqUipment used by the D0 cryo group is called the Argon Test Cell (ATC). It operates by taking a sample of the argon to be tested and running it through a test cell for purity determination. LiqUid nitrogen cooling loops are used to to keep the argon cold during the testing. The initial placement of the ATC was outside of the D0 Cryo Control Room. This was not a favorable place. mainly because of exposure to the elements on the operators and the device. A plan was made to move the ATe from outside to inside the control room. This would allow security. favorable environment conditions. and general overall improved access and operability. Havtng the ATC inside causes some concern over some issues. It is true that the ATC employs cryogenic piping components. so there is an ODH possibility ifthose components were to faU and leak. However. there are ways by which we can determine the ODH class fairly easily. Using the methods outlined in D0 EN-229. the components of the cryogenic pipelines are summed and grouped according to failure possibility and likely leakage upon failure. (Note that this is the reason that one type of component may be listed a multiple number of times in the appendix spreadsheet, as the different components have different possible leak rates. depending on position or size. etc.). The result is an ODH class 0. since the fatality rate has to be above 10{sup -7} for a hazard condition to be present. The fatality rates in this analysis only come within an order of magnitude of this safety limit due to using conservative estimates. Note that ...
Date: April 1, 1991
Creator: Michael, J.
Item Type: Report

D0 Cradle Temporary Stands

Description: While the CC Cryostat is being prepped and loaded with modules it will rest on a transporter in the Clean Room which will eventually be used to move the CC Cryostat and it's cradle onto the Center Beam. Ultimately, the Cryostat/Cradle will rest on roller/jack assemblies at each comer of the Cradle but for convenience purposes, the Cryostat/Cradle will rest on temporary stands until it is placed on the Center Beam. The stands must supply level support to the Cryostat/Cradle. The stands are designed with removable top plates which could be removed and easily machined to a desired height (thickness) such that the four stands would level the Cryostat. The stands are designed to withstand 400 tons of straight axial compression according to AISC Code. A notch is provided in the bottom surface to accomodate the keyed ways which will be installed in the Center Beam in case the need arises to use these stands when the Cryostat/Cradle is on the Center Beam. To meet Clean Room requirements, the stands were painted upon completion. Sketches and calculations are included in this report.
Date: December 1, 1988
Creator: Jaques, Al
Item Type: Report

D0 Cryo CC Heater Installation

Description: Nine pairs of heaters are installed in the bottom of the CC pressure vessel.The physical layout is shown in the CC internal development drawing, D0 dwg. 3740.510-ME-255523. Electrically the heater system is a delta configuration. Electrical details are found on D0 dwg. 3740.515EC-273761. The feedthrough connectors for power to the heaters are located in the instrumentation box. Connector positions are found on D0 dwg.3740.515-EC-273760. Original sketches for the above named drawings are included in this document. The heaters and wiring were cleaned various times prior to and after installation with ethyl a1chohol. At various stages in the installation hi-pot and continuity tests were successfully accomplished to verify the integrity of the system. The fmal hi-pot numbers are included in the documentation. The heaters and wiring are kept separated from thermometry and purity cell wiring by SS sheetmetal barriers. The fabrication, testing and installation was completed by M. Hentges and his crew from AD/Cryo.
Date: March 16, 1991
Creator: Urbin, J.
Item Type: Report

D0 Cryo-Corner Piping Flexibility Analysis

Description: Table 1 indicates that the stiffest line is the cryogenic vent line while the most flexible line is the 6 inch insulating vacuum line. The table also shows that the four remaining lines are roughly of the same stiffness. This follows closely with the experience of installing the U-tubes in the assembly hall. The vent line was by far the stiffest, while the other lines are comparitively more flexible. However, the value for the LAr line is misleading. It is as flexible as the other 1 1/2 x 3 lines. Using this as a basis, the collision hall connections should be slightly more stiff, but not appreciably. The vent line represents the only anticipated 'difficulty'. Provided that the building piping is constructed to reasonable tolerances, there should be no need to modify the existing U-tubes for use in the Collision hall. The analysis makes many assumptions which are not completely valid. For example, the inner line is much more flexible than the table indicates. Thus the analysis should not be taken as an absolute measure of the amount of force necessary to deflect the lines. The analysis does provide a means of comparison between individual lines and between the assembly hall and collision hall. The last column in tables 1 and 2 indicate which lines are the stiffest comparatively. In addition, by comparing the stiffness of each line in the collision hall with the corresponding line in the assembly hall, a qualitative assesment can be made as to whether the lines in the collision hall are flexible enough.
Date: August 20, 1991
Creator: Clark, D.
Item Type: Report

D0 Cryo Instrument Air Backup System

Description: The D0 instrument air system for cryo controls has an emergency backup supply of nitrogen gas. The backup system consists of a high pressure tube trailer (38 tubes - 2400 psig MAWP), piping, valves, regulators and pressure monitoring instrumentation. The trailer is located south of DAB alongside the LN{sub 2} Dewar. Fixed piping ties to the trailer with a flex-hose. The piping follows the cryo piping bridge entering the south wall of DAB. where it passes through the pipe chase and into the cryo pump room (Rm 315). The high pressure gas is regulated down to 90 psig before tying into the compressor supplied instrument air system. Check valves are installed at the tee for the primary air and the backup N{sub 2}. Normal operating pressure for instrument air is 100-120 psig. With the backup supply pressure set to 90 psig, 'emergency air' is supplied whenever primary air pressure falls below 90 psig. There are two additional, outside connections to the system: one is a connection for repumping the trailer after a minimum backup volume is reached and the other is an auxiliary flex-hose connection for another trailer. All manual valves at system connections will be locked closed when not in use. The system's maximum allowable working pressure (MAWP) is 2400 psi, which is the trailer MAWP. All piping and components have a minimum 2400 psi working pressure. Actual component working pressures are included in the component list.
Date: November 20, 1990
Creator: Urbin, J.
Item Type: Report

D0 Cryo System Control System Autodialer

Description: The DO cryogenic system is controlled by a TI565-PLC based control system. This allows the system to be unmanned when in steady state operation. System experts will need to be contacted when system parameters exceed normal operating points and reach alarm setpoints. The labwide FIRUS system provides one alarm monitor and communication link. An autodialer provides a second and more flexible alarm monitor and communication link. The autodialer monitors contact points in the control system and after receiving indication of an alarm accesses a list of experts which it calls until it receives an acknowledgement. There are several manufacturers and distributors of autodialer systems. This EN explains the search process the DO cryo group used to fmd an autodialer system that fit the cryo system's needs and includes information and specs for the unit we chose.
Date: April 17, 1990
Creator: Urbin, J.
Item Type: Report

D0 Cryo System ODH and Cryo Alarm System Response

Description: The D0 Cryo System is monitored by a computerized process control system and an ODH safety system. During steady state operations the cryo system will be unmanned and system experts will depend on communication systems for notification of system problems. The FIRUS system meets the minimum communication requirement and is supplemented with an autodialer which attempts to contact cryo operators by pager or phone. The RD/Safety Department requires the ODH monitor system to be connected to the labwide FIRUS system. which enables the Communications Center to receive alarms and notify the proper experts of the condition. The ODH system will have two alarm points. One for an ODH alarm and one for a system trouble alarm. The autodialer system has replaced a former cryo operations summation alarm point in the FIRUS system. This has freed space on the FIRUS system and has allowed the cryo experts more flexibility in setting up their own communication link. The FIRUS and the autodialer systems receive alarms and access lists of experts to call for notification of problems. Attempts to contact these experts will continue until the alarm or alarms is acknowledged.
Date: April 5, 1990
Creator: Urbin, J.; Dixon, K. & /Fermilab
Item Type: Report

D0 Cryo Ventilation Fan Controls and Monitoring

Description: This engineering note describes how exhaust fan 6 (EF-6) and exhaust fan 7 (EF-7) are controlled and monitored. Since these two fans are a vital link in the ODH safety system, they will be monitored, controlled and periodically operated by the programmable logic controller (PLC). If there should be a fault in the ventilation system, the PLC will print a warning message to the cryo control room printer and flash a descriptive warning on the ODH/ventilation graphics page. This fault is also logged to the Xpresslink graphics alarm page and to an alarm history hard disk file. The ventilation failure is also an input to the auto dialer which will continue it's automatic sequence until acknowledged. EF-6 delivers 13000 C.F.M. and is considered emergency ventilation. EF-7 delivers 4500 C.F.M. and will run 24 hrs a day. Both ventilation fans are located in an enclosed closet in the TRD gas room. Their ductwork, both inlets and outlets run along side the pipe chase, but are separated by an airtight wall. Their combination motor control starter cabinets are located in the TRD room in plain visible sight of the fans with the closet door open. The fans have signs that state they are automatically controlled and can energize at any time.
Date: February 15, 1990
Creator: Markley, D.
Item Type: Report

D0 Cryogenic Auto Dialing Alarm System

Description: The Automatic Dialing system purchased by D0 is intended to help make the D0 cryogenic system operate unattended by cryogenic operating personnel. The auto dialer is completely programmable and is voice synthesized. The auto dialer was purchased with 32 bistable inputs, but is expandable to 64 bistable inputs with the purchase of more electronic cards at an approximate cost of $260 per card (8 bistable inputs). The auto dialer also has the capability for analog inputs, analog outputs, and bistable outputs none of which D0 uses or intends to use. The auto dialer can be called on its operating phone line to describe current alarms with the proper password. The Auto Dialer can dial lab extensions, lab pagers, and any number outside the lab. It cannot dial a long distance pager. The auto dialer monitors alarms and alarm conditions via the T1565 PLC, upon an alarm condition it initiates a phone calling sequence of preprogrammed lists with assigned priorities. When someone is reached, the auto dialer describes the individual alarm it is calling for, by a preprogrammed set of words for that individual alarm, spoken by a female voice. The called person then has a chance to acknowledge the alarm over the telephone, if the alarm is not acknowledged the auto dialer will disconnect and call the next person on the list. The auto dialer will continue to cycle through the list until it is acknowledged, reset, or the alarm condition no longer exists.
Date: August 3, 1992
Creator: Markely, D.
Item Type: Report

D0 Cryogenic Controls I/O Base Power Distribution

Description: The D0 cryogenic control system has 3 I/O bases and 1 25 amp 24vdc power supply. Each I/O base uses both 120 vac and 24 vdc. There are as many as 14 modules in each base, depending on what type of module it may require ac or dc. Then there are as many as 32 devices (instrumentation) per module. There is a power distribution network that provides power to this system. It was configured so that no conductors, devices, or components could carry or receive more current or voltage than they could safely handle. This is done to protect both personel and components from fire, heat, and electric shock.
Date: March 9, 1991
Creator: Markley, D.
Item Type: Report

D0 Cryogenic In-Line Filters

Description: The DO cryogenic system utilizes liquid argon (serving as the detector ionizing medium) and liquid nitrogen (refrigerant for the argon). In order to keep these fluids pure and minimize the likelihood of plugged instrumentation due to contamination, in-line filters will be installed on the following lines (see Cryogenic Flow Diagram, drawing 3740-ME-222394): 445LN, 412LN, 447LA, 427LA. and 422GA. The lines referred to by these labels are argon dewar LN2 supply, cryostat LN2 supply, LAr dewar fill/drain line, cryostat LAr fill/drain line, and dewar-to-cryostat argon gas line, respectively. Five filters are required. As of this writing, one has been built and tested. The others are to be identical in concept and construction.
Date: October 4, 1988
Creator: Fuerst, J. D.
Item Type: Report

D0 Cryogenic System Operator Training

Description: D0 is a collider detector. It will be operating and doing physics at the same time as CDP, therefore it has been decided to train CDP operators to operate and respond to the D0 cryogenic control system. A cryogenic operator will be required to be in residence at D0, during the cooldown and liquid Argon fill of any of the calorimeters. The cryogenic system at D0 is designed to be unmanned during steady state operation. CDP operations has 2 man cryogenic shifts 24 hours a day. It is intended that CDP operators monitor the D0 cryogenic systems, evaluate and respond to alarms, and notify a D0 cryo expert in the event of an unusual problem. A D0 cryogenic system view node has been installed at CDP to help facilitate these goals. It should be noted that even though the CDP view node is a fully operational node it is intended that it be more of an information node and is therefore password protected. The D0 cryo experts may reassess the use of the CDP node at a later date based on experience and operating needs. This engineering note outlines the format of the training and testing given to the CDP operators to make them qualified D0 operators.
Date: November 30, 1991
Creator: Markley, D.
Item Type: Report

D0 Cryogenic System Superconducting Solenoid Platform I/O

Description: The Dzero detector is scheduled for a major upgrade between 1996 and 1999. This note describes the specifications and configuration of the physical Input/Output devices and instrumentation of the 2 Tesla Superconducting Solenoid. The Solenoid and the VLPC cryostats both reside on the detector platform and are cooled by the Dzero Helium Refrigerator. The cryogenic process control s for these two components will be an extension of the TI565 programmable logic controller system used for other Dzero cryogenic controls. Two Input/Output Bases will be installed on the Dzero detector platform near the cryo corner. These I/O bases will handle all the sensor input and process control output devices from the Solenoid and VLPC cryostats. Having the I/O bases installed on the detector platform makes the connecting cabl ing to the platform much easier . All the instruments are wired directly to the I/O base. The bases have only one communications network cabl e that must be routed off the platform to the South side of the Dzero building.
Date: October 9, 1997
Creator: Markley, D. & /Fermilab
Item Type: Report

D0-D bar 0 mixing and rare charm decays

Description: We review the current status of flavor-changing neutral currents in the charm sector. We focus on the standard-model predictions and identify the main sources of theoretical uncertainties in both D{sup 0} - {bar D}{sup 0} mixing and rare charm decays. The potential of these observables for constraining short-distance physics in the standard model and its extensions is compromised by the presence of large nonperturbative effects. We examine the possible discovery windows in which short-distance physics can be tested and study the effects of various extensions of the standard model. The current experimental situation and future prospects are reviewed.
Date: October 8, 2003
Creator: Burdman, Gustavo & Shipsey, Ian
Item Type: Article

D0 - D0bar Mixing: An Overview

Description: Recently, the B factory experiments BABAR and Belle as well as the CDF collaboration found evidence for mixing in the D meson system. The current status (beginning of summer 2008) of the experimental results of D{sup 0} mixing is summarized. In this paper, we present an overview of D{sup 0} mixing. After an introduction to the charm mixing phenomenology and analysis techniques, results of the mixing parameters and CP violation as related to mixing are summarized. They are obtained from hadronic two-body, multi-body final states and from quantum correlated D{sup 0} decays of the experiments BABAR, Belle, Cleo and CDF. Mixing results from semileptonic D{sup 0} decays can be found elsewhere.
Date: November 14, 2011
Creator: Marks, Jorg & U., /Heidelberg
Item Type: Article

D0 data handling operational experience

Description: We report on the production experience of the D0 experiment at the Fermilab Tevatron, using the SAM data handling system with a variety of computing hardware configurations, batch systems, and mass storage strategies. We have stored more than 300 TB of data in the Fermilab Enstore mass storage system. We deliver data through this system at an average rate of more than 2 TB/day to analysis programs, with a substantial multiplication factor in the consumed data through intelligent cache management. We handle more than 1.7 Million files in this system and provide data delivery to user jobs at Fermilab on four types of systems: a reconstruction farm, a large SMP system, a Linux batch cluster, and a Linux desktop cluster. In addition, we import simulation data generated at 6 sites worldwide, and deliver data to jobs at many more sites. We describe the scope of the data handling deployment worldwide, the operational experience with this system, and the feedback of that experience.
Date: August 11, 2003
Creator: al., Lee Lueking et
Item Type: Article

D0 Decomissioning : Storage of Depleted Uranium Modules Inside D0 Calorimeters after the Termination of D0 Experiment

Description: Dzero liquid Argon calorimeters contain hadronic modules made of depleted uranium plates. After the termination of DO detector's operation, liquid Argon will be transferred back to Argon storage Dewar, and all three calorimeters will be warmed up. At this point, there is no intention to disassemble the calorimeters. The depleted uranium modules will stay inside the cryostats. Depleted uranium is a by-product of the uranium enrichment process. It is slightly radioactive, emits alpha, beta and gamma radiation. External radiation hazards are minimal. Alpha radiation has no external exposure hazards, as dead layers of skin stop it; beta radiation might have effects only when there is a direct contact with skin; and gamma rays are negligible - levels are extremely low. Depleted uranium is a pyrophoric material. Small particles (such as shavings, powder etc.) may ignite with presence of Oxygen (air). Also, in presence of air and moisture it can oxidize. Depleted uranium can absorb moisture and keep oxidizing later, even after air and moisture are excluded. Uranium oxide can powder and flake off. This powder is also pyrographic. Uranium oxide may create health problems if inhaled. Since uranium oxide is water soluble, it may enter the bloodstream and cause toxic effects.
Date: September 21, 2011
Creator: Sarychev, Michael & /Fermilab
Item Type: Report

D0 Detector Assemble Hall Platform Oxygen Deficiency Hazard Analysis

Description: Liquid cryogens, released and warming to atmosphere conditions, expand to, on average, seven hundred times their liquid volume, and displace vital atmospheric oxygen. An oxygen deficiency hazard analysis assesses the increased risk to personnel in areas containing cryogenic systems. The D0 detector platform area ODH analysis has been approached four different ways using established methods. In each case, the analysis shows the platform area to be ODH class 0 as equipped (with ventilation fans) and requiring no special safety provisions. System designers have provided for a reduced oxygen level detection and warning system as well as emergency procedures to address fault conditions. The Oxygen Deficiency Hazard of any particular area is defined by these parameters: the nature of the accidental supply of inert gas (probability of occurrence and quantity then released), the area's volume, the area's ventilation rate, and to a small degree the elevation of the area. Once this information is assembled, the ODH classification can be determined through standardized calculations. The platform area under the D0 detector contains much of the cryogenic and gas system piping necessary for the D0 experiment. Prior to moving the detector into the Collision Hall, the liquid argon calorimeters are cooled down and operated in the Assembly Hall. The first phase of this operation involved the cooldown of the Central Calorimeter, which was done in February 1991. This engineering note assesses the increased risk to personnel in the platform level to a reduced oxygen atmosphere during the cool down and subsequent operation of the calorimeters in the Assembly Hall. In addition, it outlines the steps taken to warn personnel of an emergency and to direct the subsequent evacuation. This note analyses only the Assembly Hall area. A similar engineering note, EN-332, covers the analysis of the Collision Hall area.
Date: January 29, 1991
Creator: Clark, D.; Michael, J. & /Fermilab
Item Type: Report